Thor Trends 12

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Time trends in the incidence of work-related ill-health in the UK, 1996-2011: estimation from

THOR surveillance data

Carder M, McNamee R,Hussey L, Turner S, Agius R

Centre for Occupational and Environmental Health, Health Sciences Group,School of Community Based Medicine, Faculty of Medical and Human

Sciences, the University of Manchester

http://www.medicine.manchester.ac.uk/oeh/research/thor/

September 2012


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EXECUTIVE SUMMARY

BACKGROUND: This report describes the latest analyses of case reports

collected by The Health and Occupation Research (THOR) network to

investigate the trend in the physician reported incidence of work-related

illness (WRI) over time. Case reports of WRI from the three THOR schemes

currently supported by HSE were analysed: skin disease reported to

EPIDERM by dermatologists (1996-2011), respiratory disease reported to

SWORD by chest physicians (1999-2011), and (any) WRI reported to THOR-

GP by general practitioners (2006-2011).

METHOD: The methodology employed remained unchanged from that

described previously. The statistical software package STATA was used to fit

longitudinal, negative binomial (i.e. over-dispersed) Poisson models with

random effects. The dependent variable was the number of actual cases,

including zeros, per reporter per month. Variables were also included to

represent season, reporter type (core or sample), and first month/s as a

new reporter. Changes in the population base were accounted for by

including an offset variable representing the UK working population for each

year. Change in incidence was measured in two different ways related to the

treatment of calendar time in the model: a non-parametric approach

containing separate indicators for different years (2011 as the reference year)

and a parametric approach with continuous time variable measured on a

scale of years.

RESULTS: Case reports of skin disease to EPIDERM were predominantly

contact dermatitis (CD) (81%) with smaller proportions of neoplasia (12%) and

other skin diagnoses. Overall the addition of a further year of data (2011) had

little impact on the annual average change in incidence of work-related skin

disease which remained similar to those previously reported i.e. indicating a

small but significant yearly reduction in incidence. The updated results were

-3.4% (95% CIs:-3.9, -2.8) for all skin diagnoses, -3.3% (95% CIs:-3.9,-2.6) for

CD, -5.6% (95% CIs:-7.5, -3.6) for contact urticaria and -2.6% (95% CIs:-4.1,

-1.0) for neoplasia. Relative rates by year, however, suggested a larger


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with previous observations regarding the annual average estimated change in

incidence of the categories of work-related illness investigated here. For

dermatologists and chest physicians, the reported incidence was observed

either to be falling (contact dermatitis, contact urticaria, neoplasia, asthma,

mesothelioma) or to remain relatively unchanged over time (benign pleural

plaques, pneumoconiosis). In addition to simply observing these trends,

recent THOR work has begun to investigate to what extent the observed

changes are the result of changes in legislation, regulatory activity and market

forces, relating to specific substances such as latex, chromium and

glutaraldehyde. The application of the MLM methodology to investigate

interventions such as these, has proved to be a useful tool and further work is

anticipated in this area.

The estimated annual change in incidence based on data from GPs also

remained relatively unchanged with the addition of the 2011 data, with a

decrease in incidence over time observed for all the disease groups

investigated. However, the impact of the changes in sampling methodology,

resulting from the cessation of funding to GPs for participation, on the

estimates of trend is yet to be fully understood.

It is also possible that the trends in GPs as well as in specialists have been

influenced by reporter fatigue. A large body of work has been carried out to

date investigating this issue within THOR with some evidence of fatigue

present for some (but not all) physician groups and types (core or sample) as

suggested by an increase in nil returns, non-response and excess zeros over

time. The implications of these findings are under review.

CONCLUSION: Annual reports describing the trend in incidence of work-

related illness, as reported by medical physicians to THOR, have been

provided to HSE since 2006. To date, this has generated a large and

invaluable body of work not only providing annual updates of the trends but

also describing ongoing developments in the methodology, including

investigations of the important issue of reporter fatigue. Some of the observed

trends have remained relatively unchanged with the addition of each


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successive year of data and are in accordance with those expected as a

result of Government initiatives (for example, the decline in incidence of

asthma, contact dermatitis and contact urticaria), with further work by this

group investigating these trends in relation to specific sectors or agents. For

others, in particular the asbestos related diseases, the observed trends have

shown a greater degree of variation and may, at least in part, reflect a change

in management and referral patterns rather than a true trend. Ongoing work,

including benchmarking with other data sources will help clarify these issues

further. Since 2009, the annual trends reports have also analysed data

reported by GPs. However, these GP data should be interpreted with caution

until issues such as the impact of reporting activity and reporter fatigue are

better understood. Work continues to improve the THOR trends methodology

to enable these and other partially resolved issues to be investigated further.


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CONTENTS

Page number1 BACKGROUND 10

2 METHOD 10

3 RESULTS 133.1 OVERVIEW OF SCHEMES 133.1.1 EPIDERM 133.1.2 SWORD 133.1.3 THOR-GP 143.2 TIME TRENDS BY DISEASE CATEGORY 143.2.1 TOTAL WORK-RELATED ILLNESS 153.2.2 WORK-RELATED SKIN DISEASE 173.2.3 WORK-RELATED RESPIRATORY DISEASE 37

3.2.4 WORK-RELATED MUSCULOSKELETAL DISORDERS 513.2.5 WORK-RELATED MENTAL ILL-HEALTH 56

4 DISCUSSION 60

5 CONCLUSION 67


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LIST OF TABLES

Pagenumber

1 Data period for trends analyses 11

2 Categories of illness included in the analyses 123 Average annual percentage change in risk in total work-

related ill-health16

4 Relative rates by year, with 95% comparison intervals,total work-related ill-health (2011 estimate =1)

16

5 Average annual percentage change in reportedincidence in work-related skin disease

19

6 Relative rates by year, with 95% comparison intervals,total skin disease (2011 estimate =1)

20

7 Relative rates by year, with 95% comparison intervals,all contact dermatitis (2011 estimate =1)

23

8 Relative rates by year, with 95% comparison intervals,allergic contact dermatitis (2011 estimate =1)

25

9 Relative rates by year, with 95% comparison intervals,irritant contact dermatitis (2011 estimate =1)

27

10 Relative rates by year, with 95% comparison intervals,mixed contact dermatitis (2011 estimate =1)

29

11 Relative rates by year, with 95% comparison intervals,contact urticaria (2011 estimate =1)

31

12 Relative rates by year, with 95% comparison intervals,neoplasia (2011 estimate =1)

33

13 Relative rates by year, with 95% comparison intervals,other skin* (2011 estimate =1)

35

14 Average annual percentage change in reportedincidence in work-related respiratory disease

38

15 Relative rates by year, with 95% comparison intervals,total respiratory disease (2011 estimate =1)

39

16 Relative rates by year, with 95% comparison intervals,asthma (2011 estimate =1)

41

17 Relative rates by year, with 95% comparison intervals,mesothelioma (2011 estimate =1)

43

18 Relative rates by year, with 95% comparison intervals

(2011 estimate =1), benign pleural plaques

45

19 Relative rates by year, with 95% comparison intervals,pneumoconiosis (2011 estimate =1)

47

20 Relative rates by year, with 95% comparison intervals,other* respiratory disease (2011 estimate =1)

49

21 Average annual percentage change in reportedincidence in work-related musculoskeletal disorders

51

22 Relative rates by year, with 95% comparison intervals,total musculoskeletal disorders (2011 estimate = 1)

52

23 Relative rates by year, with 95% comparison intervals,upper limb disorders (2011 estimate = 1)

53

24 Relative rates by year, with 95% comparison intervals,spine/back disorders (2011 estimate = 1)

54


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25 Relative rates by year, with 95% comparison intervals,lower limb disorders (2011 estimate = 1)

55

26 Average annual percentage change in reportedincidence in work-related mental ill-health

56

27 Relative rates by year, with 95% comparison intervals,

total mental ill-health (2011 estimate = 1)

57

28 Relative rates by year, with 95% comparison intervals,anxiety and depression (2011 estimate = 1)

58

29 Relative rates by year, with 95% comparison intervals,other work stress (2011 estimate = 1)

59

LIST OF FIGURES

Page

number1 Relative rates by year (2011 estimate = 1), with 95%

comparison intervals, total work-related ill-health16

2 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total skin disease

21

3 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, all contact dermatitis

24

4 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, allergic contact dermatitis

26

5 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, irritant contact dermatitis

28

6 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, mixed contact dermatitis

30

7 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, contact urticaria

32

8 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, neoplasia

34

9 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, other (than contact dermatitis)skin

36

10 Relative rates by year (2011 estimate = 1), with 95%

comparison intervals, total respiratory disease

40

11 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, asthma

42

12 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, mesothelioma

44

13 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, benign pleural plaques

46

14 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, pneumoconiosis

48

15 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, other respiratory disease

50

16 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total musculoskeletal disorders

52


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17 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, upper limb disorders

53

18 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, upper limb disorders

54

19 Relative rates by year (2011 estimate = 1), with 95%

comparison intervals, lower limb disorders

55

20 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total mental ill-health

57

21 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, anxiety and depression

58

22 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, other work stress

59

LIST OF APPENDICESPage number

A Descriptive analyses 71


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1. BACKGROUND

This report describes the latest analyses of case reports collected by The

Health and Occupation Research (THOR) network1to investigate the trend in

incidence of work-related illness (WRI) over time. This report should not be

viewed as a stand-alone report but should be viewed in conjunction with

previous reports submitted to the Health and Safety Executive (HSE) which

provide much fuller detail regarding the THOR network, the rationale behind

the study and advances in the methodology over time2-8. For the present

study, data from the three THOR schemes currently supported by HSE were

analysed: case reports of work-related skin disease reported to EPIDERM by

dermatologists (1996-2011), case reports of work-related respiratory disease

reported to SWORD by chest physicians (1999-2011), and case reports of

(any) WRI reported to THOR-GP by general practitioners (2006-2011).

2. METHOD

The methodology employed in this study has been described in full in

previous reports2-8and only a brief summary is provided here. The data period

and diagnostic groups analysed are shown in Tables 1 and 2. Analyses were

based on all reporters in each scheme combined, and separately (where

appropriate) for core (i.e. physicians reporting every month) or sample (i.e.

physicians reporting for one randomly selected month per year) reporting

groups. A brief history of the individual schemes, including any significant

changes to the proportion of core to sample reporters over time, was provided

in the trends report submitted to HSE in 20112. The only substantial change in

2011 was for THOR-GP, which moved from 80% sample reporting in 2010 to

100% sample reporting in 2011. For the present report, analyses of THOR-GP

data were based on all reporters (i.e. core and sample combined) only, with

no separate analysis by reporter type (core only or sample only). Core only

analyses were not carried out because core reporting stopped in December

2010, with core only trends for the period 2006-2010 reported on in the trends

report submitted in 20112

. Sample only analyses were not carried out because

prior to 2010 only a small proportion (4%) of GPs reported on a sample basis;


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Table 2 Categories of illness included in the analyses

Clinical specialist THOR-GP

All WRI - Yes

Total skin Yes YesContact dermatitis (CD) Yes -

Allergic CD Yes -

Irritant CD Yes -

Mixed CD Yes -

Neoplasia Yes -

Contact urticaria Yes -Other skina Yes -

Total respiratory Yes -Asthma Yes -

Mesothelioma Yes -Benign pleural disease Yes -

Pneumoconiosis Yes -Other respiratory diseaseb Yes -

Total musculoskeletal - YesUpper limb disordersc - YesSpine/back disorders - Yes

Lower limb disorderse - Yes

Total mental ill-health - YesAnxiety and depression - Yes

Other work stress - YesaOther than contact dermatitis

bOther than asthma, mesothelioma, benign pleural disease or pneumoconiosis

cHand/wrist/arm, shoulder and elbow

dNeck/thoracic spine, lumbar spine/trunk

eHip/knee, ankle/foot


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3. RESULTS

3.1 OVERVIEW OF SCHEMES

An overview of the reporting activity of the physicians participating in

EPIDERM, SWORD, and THOR-GP is provided in Appendix A and briefly

described below.

3.1.1 EPIDERM

A total of 415 dermatologists have been enrolled in EPIDERM during the

study period with 93% actively participating at least once (i.e. either returning

cases or declaring I have nothing to report this month). 2011 saw a small

decrease in the overall number of physicians in EPIDERM (from 181 in 2010

to 175 in 2011) and a decrease in the average number of active reporters per

month (26 per month in 2010 to 21 per month in 2011). However, the average

cases per active reporter remained little changed between the two years (2.4

in 2010 and 2.2 in 2011). Reporters to EPIDERM are predominantly sample

(86% in 2011) but core reporters report more cases per active reporter per

month (3.7) compared to sample (0.9). Case reports to EPIDERM continue tobe predominantly contact dermatitis (81% of total cases) with smaller

proportions of neoplasia (12%) and other skin diagnoses.

3.1.2 SWORD

Active participation in SWORD during the study period was similar to

EPIDERM with 94% of the 798 chest physicians enrolled during this periodactively reporting at least once. Although the total number of reporters in

SWORD fell slightly between 2010 and 2011 (474 to 460) the average number

of active reporters per month was similar (37 in 2010 and 35 in 2011) and the

average number of cases per active reporter actually slightly increased (1 in

2010 to 1.2 in 2011). Similar to EPIDERM, the smaller group of chest

physicians reporting as core reported more cases per active reporter per

month than chest physicians reporting as sample. The majority of the actual

diagnoses (44%) reported to SWORD during the study period were benign


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pleural plaques. Of the remaining cases 20% were mesothelioma, 19%

asthma, 8% pneumoconiosis, and 12% other respiratory disease.

3.1.3 THOR-GP

THOR-GP differs to EPIDERM and SWORD in that at the start of the study

period (2006) all GPs reported to THOR-GP on a core basis whilst at the end

of the study period (2011) reporting was exclusively sample, with the majority

of the switch from core to sample occurring in 2010. Active participation during

this period was lower than observed for SWORD and EPIDERM (76% of the

699 GPs ever enrolled). In contrast to the clinical specialists, GPs participating

as sample physicians reported on average more cases per active reporter per

month than GPs participating as core reporters. Thus, although the switch to

100% sample meant that there was a substantial decrease in the average

number of active reporters per month between 2010 and 2011 (47 to 15), the

average number of cases per active reporter month actually increased

between 2010 and 2011 (0.9 to 1.4). Musculoskeletal and mental ill-health

case reports comprised the majority (52% and 32%, respectively) of the cases

reported to THOR-GP with smaller proportions of skin (10%), respiratory (2%)

and other diagnoses (4%).

3.2 TIME TRENDS BY DISEASE CATEGORY

This report continues with the approach first adopted in the trends report

submitted to HSE in September 20103, in that the statistical uncertainty

(confidence intervals) in the graphs illustrating time trends are presented in

such a way as to allow the reader to assess the significance of the difference

between any two years. This approach suggested by the HSE liaison officer

when steering the research follows the method described by Firth and de

Menezes10 which assigns a confidence (or comparison) interval to the

reference category (2011 in the present analyses) and reduces the width of

the confidence (comparison) intervals of non-reference categories in such a

way that all pairwise comparisons between years can validly be made using

these adjusted confidence intervals.


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3.2.1 TOTAL WORK-RELATED ILLNESS

The average annual percentage change in risk of total WRI, as reported to

THOR-GP is shown in Table 3 whilst the relative rates by year are shown in

Table 4 and Figure 1. For the period 2006-2011, the average annual decrease

in incidence was -12.5% (95% CIs: -15, -10). This remains little changed from

the last reported estimate (for the period 2006-2010) which was very similar at

-12.3% (95% CIs: -14.8, -9.7). The graphs showing relative rates by year for

THOR-GP suggest the slight rise in incidence observed in 2010 has been

followed by a fall in 2011. However, it should be noted that the confidence

intervals are wider in 2010 and (especially) 2011, (reflecting the move to a

greater proportion of sample reporters) and overlap earlier years.


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Table 3 Average annual percentage change in risk in total work-related illness

ESTIMATED % CHANGE(95% CONFIDENCE INTERVAL)

Reporters Year (continuous) THOR-GP

All 2006-2011 -12.5 (-15, -10)

Table 4 Relative rates by year, with 95% comparison intervals, totalwork-related ill-health (2011 estimate =1)

Relative rates (95% comparison interval)

THOR-GP

Reporter Group Year

All 2006 1.74 (1.61, 1.88)

2007 1.39 (1.30, 1.48)

2008 1.30 (1.20, 1.40)

2009 1.06 (0.98, 1.14)2010 1.23 (1.09, 1.38)

2011 1.00 (0.83, 1.20)

Figure 1 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total work-related ill-health

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.82

2006 2007 2008 2009 2010 2011

Relativerate

Year

THORGP, all reporters


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3.2.2 WORK-RELATED SKIN DISEASE

The average annual percentage change in risk of work-related skin disease,

as reported by dermatologists and GPs is shown in Table 5 whilst the relative

rates by year are shown in Tables 6 to 13 and Figures 2 to 9.

For both dermatologists and GPs, the addition of a further year of data (2011)

had little impact on the annual average change in incidence of work-related

skin disease which remained at -3.4% (95% CIs: -3.9, -2.8) for dermatologists

and increased slightly from -5.3% (2006-2010) to -5.7% (95% CI: -13.2, 2.3)

for GPs (2006-2011). Analyses restricted to case reports from dermatologists

during 2006-2011 (thus enabling a direct comparison with GP case reports)

suggested a steeper decrease in incidence for GPs compared to

dermatologists. Although the annual average change in incidence remained

little changed after the addition of 2011 data, the graphs showing relative

rates by year suggest a large decrease in incidence for dermatologists

between 2010 and 2011 compared to changes in previous years. Analyses

based on reporter type (i.e. core only or sample only) suggest that this

decrease occurred amongst the core reporters rather than the sample

reporters. The graph showing relative rates by year for THOR-GP suggeststhe slight increase observed for 2010 has been followed by a further increase

in 2011. However, trends based on GP data should be viewed with caution as

results are based on relatively few cases (confidence intervals are overlapping

for all years).

The predicted trend for contact dermatitis (CD) was very similar to that

observed for total work-related skin disease. For dermatologists, in addition toall contact dermatitis combined, further analyses by type of CD were carried

out. As reported previously, a steeper decrease in the incidence of allergic CD

was observed (-5.4% (95% CIs: -6.3, -4.6)) compared to irritant CD (-1.2 (95%

CIs: -2.1, -0.3)) or mixed CD (-2.2% (95% CIs: -3.5, -0.8)). Restricting the

analyses to cases reported by core reporters had little effect on the observed

trend for these CD sub-categories. For sample only analyses however, the

percentage decrease in allergic CD and irritant CD were very similar (2-3%).


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The annual average change in incidence of both urticaria and neoplasia

(investigated for dermatologists only) also remained little changed by the

addition of the 2011 data with the previously observed variation between

reporter type (decrease in incidence observed for core reporters and increase

for sample reporters) still apparent. Of interest, the large fall in incidence

between 2010 and 2011 observed for CD was similarly observed for

neoplasia, with the drop again appearing to be largely driven by a decrease in

case reports from core reporters. However, it should be noted that the

confidence intervals for 2011 are very wide and overlap previous years,

making it difficult to draw any firm conclusions.

For the purpose of this study, the group other skin referred to all non CD

cases (and therefore included all of the groups already discussed, other then

CD). As expected from the individual group analyses, an overall downward

trend was predicted for this group. Some variation between core and sample

reporters was observed for EPIDERM, but this was probably largely driven by

the (already discussed) core and sample differences for neoplasia.


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Table 5 Average annual percentage change in reported incidence inwork-related skin disease

a) All reporters


Year(continuous)

EPIDERM THOR-GP

Total skin 1996-2011 -3.4 (-3.9, -2.8) /

2006-2011 -2.0 (-4.3, 0.4) -5.7 (-13.2, 2.3)

Contact dermatitis (CD) 1996-2011 -3.3 (-3.9, -2.6) /

Allergic CD 1996-2011 -5.4 (-6.3, -4.6) /

Irritant CD 1996-2011 -1.2 (-2.1,-0.3) /

Mixed CD 1996-2011 -2.2 (-3.5,-0.8) /

Urticaria 1996-2011 -5.6 (-7.5, -3.6) /

Neoplasia 1996-2011 -2.6 (-4.1, -1.0) /Other* skin 1996-2011 -3.2 (-4.3, -2.0) /

b) Core reporters

ESTIMATED % CHANGE(95% CONFIDENCEINTERVAL)

Year (continuous) EPIDERM

Total skin 1996-2011 -3.6 (-4.2, -3.0)

Contact dermatitis (CD) 1996-2011 -3.3 (-4.0, -2.7)

Allergic CD 1996-2011 -6.0 (-6.9, -5.0)

Irritant CD 1996-2011 -1.1 (-2.0, -0.1)

Mixed CD 1996-2011 -2.3 (-3.7, -0.9)

Urticaria 1996-2011 -6.2 (-8.2, -4.2)

Neoplasia 1996-2011 -4.6 (-6.2, -3.0)Other* skin 1996-2011 -4.5 (-5.7, -3.3)

c) Sample reporters


Year(continuous)

EPIDERM

Total skin 1996-2011 -1.3 (-3.1, 0.5)

Contact dermatitis (CD) 1996-2011 -2.7 (-4.6, -0.6)

Allergic CD 1996-2011 -1.8 (-4.5, 1.0)

Irritant CD 1996-2011 -2.5 (-5.3, 0.5)

Mixed CD 1996-2011 -0.3 (-4.7, 4.3)

Urticaria 1996-2011 1.2 (-6.4, 9.5)

Neoplasia 1996-2011 6.7 (2.8, 10.6)Other* skin 1996-2011 3.9 (0.8, 7.1)*Other than contact dermatitis


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Table 6 Relative rates by year, with 95% comparison intervals, totalskin disease (2011 estimate =1)


EPIDERM THOR-GP

Reporter Group Year

All 1996 1.71 (1.58, 1.86) /

1997 1.82 (1.69, 1.96) /

1998 1.67 (1.54, 1.80) /

1999 1.71 (1.59, 1.85) /

2000 1.57 (1.45, 1.71) /

2001 1.45 (1.34, 1.56) /

2002 1.41 (1.30, 1.52) /

2003 1.41 (1.31, 1.52) /

2004 1.30 (1.20, 1.40) /

2005 1.32 (1.22, 1.43) /

2006 1.16 (1.07, 1.26) 0.98 (0.79, 1.23)

2007 1.22 (1.12, 1.32) 0.91 (0.74, 1.11)

2008 1.13 (1.03, 1.24) 0.93 (0.76, 1.14)

2009 1.30 (1.19, 1.42) 0.76 (0.60, 0.96)

2010 1.22 (1.11, 1.35) 0.81 (0.58, 1.12)

2011 1.00 (0.89, 1.13) 1.00 (0.58, 1.73)

Core 1996 1.80 (1.65, 1.96) /

1997 1.92 (1.78, 2.07) /

1998 1.75 (1.62, 1.89) /

1999 1.79 (1.65, 1.93) /

2000 1.68 (1.54, 1.82) /

2001 1.51 (1.39, 1.64) /

2002 1.44 (1.33, 1.56) /

2003 1.49 (1.38, 1.61) /

2004 1.34 (1.23, 1.45) /2005 1.36 (1.25, 1.48) /

2006 1.17 (1.07, 1.27) /

2007 1.26 (1.16, 1.38) /

2008 1.19 (1.08, 1.30) /

2009 1.34 (1.23, 1.47) /

2010 1.26 (1.13, 1.39) /

2011 1.00 (0.88, 1.14) /

Sample 1996 1.00 (0.73, 1.37) /

1997 1.22 (0.93, 1.61) /

1998 1.14 (0.89, 1.46) /

1999 1.23 (0.98, 1.53) /2000 0.99 (0.78, 1.26) /

2001 1.09 (0.87, 1.37) /

2002 1.26 (0.99, 1.61) /

2003 0.90 (0.68, 1.18) /

2004 1.05 (0.82, 1.35) /

2005 1.05 (0.82, 1.34) /

2006 1.21 (0.96, 1.51) /

2007 0.93 (0.72, 1.20) /

2008 0.78 (0.57, 1.07) /

2009 1.04 (0.78, 1.39) /

2010 1.00 (0.74, 1.35) /

2011 1.00 (0.73, 1.38) /Models adjusted for reporter type (where appropriate), season and harvestingPopulation offset included in the model


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Figure 2 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total skin disease

a) EPIDERM

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year

EPIDERM, all reporters

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year

EPIDERM, core reporters

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year

EPIDERM, sample reporters


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b) THOR-GP

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.82

2006 2007 2008 2009 2010 2011

Relativerate

Year

THORGP, all reporters


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Table 7 Relative rates by year, with 95% comparison intervals, allcontact dermatitis (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 1.64 (1.50, 1.80)

1997 1.76 (1.62, 1.90)

1998 1.64 (1.51, 1.78)

1999 1.67 (1.54, 1.81)

2000 1.48 (1.36, 1.62)

2001 1.35 (1.24, 1.47)

2002 1.41 (1.30, 1.53)

2003 1.38 (1.26, 1.50)

2004 1.25 (1.15, 1.36)

2005 1.25 (1.14, 1.37)

2006 1.10 (1.00, 1.20)

2007 1.15 (1.05, 1.26)

2008 1.10 (1.00, 1.22)

2009 1.29 (1.17, 1.41)

2010 1.23 (1.11, 1.36)

2011 1.00 (0.88, 1.13)

Core 1996 1.69 (1.53, 1.86)

1997 1.83 (1.68, 1.99)

1998 1.71 (1.57, 1.86)

1999 1.70 (1.56, 1.85)

2000 1.55 (1.41, 1.70)

2001 1.41 (1.29, 1.55)

2002 1.43 (1.31, 1.56)

2003 1.44 (1.32, 1.57)

2004 1.29 (1.19, 1.41)2005 1.28 (1.16, 1.40)

2006 1.12 (1.01, 1.23)

2007 1.19 (1.08, 1.32)

2008 1.15 (1.04, 1.28)

2009 1.33 (1.20, 1.46)

2010 1.26 (1.14, 1.41)

2011 1.00 (0.88, 1.14)

Sample 1996 1.14 (0.81, 1.59)

1997 1.21 (0.89, 1.63)

1998 1.17 (0.88, 1.56)

1999 1.40 (1.11, 1.78)2000 1.04 (0.80, 1.36)

2001 0.95 (0.72, 1.24)

2002 1.32 (1.01, 1.73)

2003 0.88 (0.65, 1.21)

2004 0.90 (0.66, 1.22)

2005 1.05 (0.80, 1.39)

2006 1.00 (0.76, 1.31)

2007 0.78 (0.58, 1.06)

2008 0.71 (0.50, 1.02)

2009 0.91 (0.65, 1.27)

2010 0.93 (0.66, 1.31)

2011 1.00 (0.70, 1.44)Models adjusted for reporter type (where appropriate), season and harvestingPopulation offset included in the model


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Figure 3 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, all contact dermatitis

a) EPIDERM

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 8 Relative rates by year, with 95% comparison intervals,allergic contact dermatitis (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 2.39 (2.09, 2.73)

1997 2.77 (2.48, 3.10)

1998 2.29 (2.03, 2.58)

1999 2.27 (2.01, 2.55)

2000 2.26 (2.00, 2.55)

2001 1.84 (1.61, 2.09)

2002 2.12 (1.89, 2.39)

2003 2.06 (1.83, 2.32)

2004 1.63 (1.44, 1.85)

2005 1.65 (1.45, 1.89)

2006 1.55 (1.35, 1.77)

2007 1.35 (1.16, 1.56)

2008 1.35 (1.16, 1.58)

2009 1.33 (1.14, 1.56)

2010 1.34 (1.14, 1.58)

2011 1.00 (0.82, 1.22)

Core 1996 2.64 (2.30, 3.04)

1997 3.07 (2.73, 3.45)

1998 2.59 (2.30, 2.93)

1999 2.51 (2.21, 2.84)

2000 2.53 (2.23, 2.87)

2001 2.11 (1.85, 2.41)

2002 2.25 (1.99, 2.54)

2003 2.26 (1.99, 2.55)

2004 1.79 (1.57, 2.03)2005 1.73 (1.50, 1.99)

2006 1.63 (1.41, 1.88)

2007 1.42 (1.21, 1.66)

2008 1.44 (1.23, 1.70)

2009 1.44 (1.22, 1.69)

2010 1.39 (1.17, 1.66)

2011 1.00 (0.80, 1.24)

Sample 1996 1.17 (0.74, 1.83)

1997 1.34 (0.91, 1.96)

1998 0.91 (0.59, 1.38)

1999 1.08 (0.74, 1.57)2000 1.00 (0.70, 1.44)

2001 0.64 (0.42, 0.99)

2002 1.48 (1.05, 2.09)

2003 1.07 (0.72, 1.58)

2004 0.82 (0.53, 1.28)

2005 1.18 (0.82, 1.69)

2006 1.06 (0.73, 1.54)

2007 0.88 (0.58, 1.33)

2008 0.80 (0.50, 1.27)

2009 0.72 (0.43, 1.21)

2010 0.93 (0.57, 1.50)



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Figure 4 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, allergic contact dermatitis

0

0.5

1

1.5

2

2.5

3

3.5

4

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.5

1

1.5

2

2.5

3

3.5

4

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.5

1

1.5

2

2.5

3

3.5

4

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 9 Relative rates by year, with 95% comparison intervals,irritant contact dermatitis (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 1.27 (1.12, 1.44)

1997 1.18 (1.05, 1.33)

1998 1.23 (1.10, 1.38)

1999 1.29 (1.15, 1.45)

2000 1.05 (0.92, 1.20)

2001 1.01 (0.89, 1.14)

2002 1.05 (0.93, 1.19)

2003 1.01 (0.89, 1.14)

2004 0.90 (0.80, 1.02)

2005 1.03 (0.90, 1.17)

2006 0.94 (0.83, 1.07)

2007 1.06 (0.94, 1.20)

2008 0.98 (0.86, 1.12)

2009 1.12 (0.98, 1.27)

2010 1.17 (1.03, 1.34)

2011 1.00 (0.86, 1.17)

Core 1996 1.29 (1.13, 1.48)

1997 1.21 (1.07, 1.37)

1998 1.22 (1.08, 1.38)

1999 1.29 (1.14, 1.46)

2000 1.06 (0.93, 1.22)

2001 0.99 (0.86, 1.13)

2002 1.04 (0.91, 1.18)

2003 1.01 (0.89, 1.15)

2004 0.90 (0.79, 1.03)2005 1.02 (0.90, 1.17)

2006 0.95 (0.83, 1.08)

2007 1.10 (0.97, 1.24)

2008 1.01 (0.88, 1.16)

2009 1.15 (1.01, 1.31)

2010 1.21 (1.05, 1.38)

2011 1.00 (0.85, 1.18)

Sample 1996 0.76 (0.41, 1.39)

1997 0.86 (0.51, 1.44)

1998 1.37 (0.95, 1.98)

1999 1.29 (0.90, 1.84)2000 0.95 (0.63, 1.43)

2001 1.24 (0.87, 1.76)

2002 1.30 (0.87, 1.95)

2003 0.94 (0.60, 1.49)

2004 0.89 (0.57, 1.40)

2005 1.04 (0.67, 1.60)

2006 1.01 (0.66, 1.55)

2007 0.70 (0.43, 1.16)

2008 0.69 (0.39, 1.23)

2009 0.71 (0.40, 1.27)

2010 0.78 (0.45, 1.37)



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Figure 5 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, irritant contact dermatitis

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.20.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 10 Relative rates by year, with 95% comparison intervals,mixed contact dermatitis (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 1.28 (1.04, 1.58)

1997 1.41 (1.18, 1.69)

1998 1.29 (1.07, 1.56)

1999 1.28 (1.06, 1.55)

2000 1.10 (0.89, 1.35)

2001 1.00 (0.82, 1.24)

2002 1.24 (1.04, 1.49)

2003 1.28 (1.07, 1.53)

2004 1.28 (1.08, 1.51)

2005 1.06 (0.87, 1.29)

2006 0.84 (0.68, 1.05)

2007 0.99 (0.81, 1.21)

2008 0.91 (0.73, 1.12)

2009 1.22 (0.99, 1.49)

2010 0.97 (0.77, 1.22)

2011 1.00 (0.78, 1.28)

Core 1996 1.39 (1.11, 1.73)

1997 1.53 (1.27, 1.84)

1998 1.42 (1.16, 1.73)

1999 1.38 (1.13, 1.68)

2000 1.22 (0.99, 1.50)

2001 1.18 (0.95, 1.45)

2002 1.35 (1.12, 1.63)

2003 1.45 (1.22, 1.74)

2004 1.39 (1.17, 1.65)2005 1.16 (0.95, 1.42)

2006 0.91 (0.73, 1.13)

2007 1.13 (0.91, 1.40)

2008 0.99 (0.79, 1.24)

2009 1.39 (1.13, 1.70)

2010 0.99 (0.77, 1.27)

2011 1.00 (0.76, 1.31)

Sample 1996 0.57 (0.25, 1.33)

1997 0.74 (0.39, 1.43)

1998 0.63 (0.34, 1.15)

1999 0.64 (0.37, 1.12)2000 0.47 (0.25, 0.89)

2001 0.25 (0.10, 0.61)

2002 0.67 (0.34, 1.31)

2003 0.33 (0.14, 0.80)

2004 0.70 (0.37, 1.32)

2005 0.52 (0.26, 1.05)

2006 0.54 (0.28, 1.05)

2007 0.24 (0.09, 0.65)

2008 0.40 (0.18, 0.91)

2009 0.24 (0.08, 0.74)

2010 0.89 (0.47, 1.70)



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Figure 6 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, mixed contact dermatitis

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.20.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 11 Relative rates by year, with 95% comparison intervals,contact urticaria (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 2.36 (1.66, 3.36)

1997 3.33 (2.58, 4.30)

1998 2.65 (1.98, 3.55)

1999 2.59 (1.91, 3.51)

2000 3.59 (2.80, 4.60)

2001 2.28 (1.70, 3.06)

2002 2.64 (2.02, 3.45)

2003 2.82 (2.18, 3.67)

2004 2.14 (1.60, 2.86)

2005 3.05 (2.33, 3.99)

2006 1.89 (1.35, 2.63)

2007 1.84 (1.29, 2.61)

2008 1.16 (0.75, 1.80)

2009 1.15 (0.74, 1.79)

2010 1.60 (1.08, 2.39)

2011 1.00 (0.59, 1.68)

Core 1996 2.65 (1.85, 3.80)

1997 3.82 (2.96, 4.94)

1998 3.00 (2.24, 4.03)

1999 2.87 (2.10, 3.92)

2000 4.20 (3.27, 5.38)

2001 2.59 (1.92, 3.49)

2002 2.98 (2.28, 3.91)

2003 3.26 (2.52, 4.22)

2004 2.36 (1.76, 3.16)2005 3.46 (2.64, 4.53)

2006 1.89 (1.32, 2.69)

2007 2.02 (1.41, 2.89)

2008 1.19 (0.75, 1.89)

2009 1.18 (0.74, 1.86)

2010 1.70 (1.13, 2.57)

2011 1.00 (0.58, 1.73)

Sample 1996 0.89 (0.21, 3.72)

1997 0.83 (0.20, 3.48)

1998 0.92 (0.29, 2.95)

1999 1.22 (0.48, 3.09)2000 0.69 (0.22, 2.22)

2001 0.71 (0.22, 2.30)

2002 0.75 (0.18, 3.08)

2003 0.34 (0.05, 2.43)

2004 0.92 (0.29, 2.91)

2005 0.73 (0.18, 2.97)

2006 1.88 (0.75, 4.74)

2007 0.81 (0.20, 3.30)

2008 0.83 (0.20, 3.42)

2009 1.02 (0.25, 4.27)

2010 0.98 (0.24, 4.10)



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32

Figure 7 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, contact urticaria

0

1

2

3

4

5

6

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

1

2

3

4

5

6

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

1

2

3

4

5

6

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 12 Relative rates by year, with 95% comparison intervals,neoplasia (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 1.67 (1.35, 2.06)

1997 1.58 (1.29, 1.94)

1998 1.24 (1.00, 1.55)

1999 1.32 (1.06, 1.64)

2000 1.46 (1.20, 1.79)

2001 1.52 (1.28, 1.80)

2002 1.21 (0.99, 1.47)

2003 1.27 (1.05, 1.54)

2004 1.17 (0.96, 1.43)

2005 1.10 (0.90, 1.34)

2006 1.07 (0.88, 1.30)

2007 1.25 (1.02, 1.54)

2008 1.07 (0.83, 1.38)

2009 1.33 (1.05, 1.67)

2010 1.07 (0.78, 1.45)

2011 1.00 (0.57, 1.74)

Core 1996 4.08 (3.28, 5.08)

1997 3.78 (3.07, 4.66)

1998 2.87 (2.28, 3.61)

1999 3.29 (2.63, 4.11)

2000 3.49 (2.83, 4.31)

2001 3.37 (2.80, 4.05)

2002 2.60 (2.13, 3.19)

2003 2.79 (2.31, 3.36)

2004 2.45 (2.01, 3.00)2005 2.48 (2.03, 3.04)

2006 2.04 (1.64, 2.53)

2007 2.54 (2.03, 3.19)

2008 2.30 (1.78, 2.99)

2009 2.50 (1.94, 3.23)

2010 1.86 (1.30, 2.67)

2011 1.00 (0.30, 3.31)

Sample 1996 0.37 (0.15, 0.92)

1997 0.77 (0.42, 1.42)

1998 0.55 (0.30, 1.01)

1999 0.42 (0.22, 0.79)2000 0.62 (0.36, 1.06)

2001 1.06 (0.68, 1.66)

2002 0.91 (0.52, 1.58)

2003 0.82 (0.47, 1.42)

2004 1.06 (0.66, 1.70)

2005 0.66 (0.36, 1.19)

2006 1.52 (1.02, 2.25)

2007 1.34 (0.86, 2.08)

2008 0.87 (0.48, 1.59)

2009 1.42 (0.84, 2.42)

2010 1.28 (0.74, 2.21)



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Figure 8 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, neoplasia

0

0.5

1

1.5

2

2.5

3

3.5

44.5

5

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.51

1.5

2

2.5

3

3.5

4

4.5

5

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 13 Relative rates by year, with 95% comparison intervals, otherskin* (2011 estimate =1)


EPIDERM

Reporter Group Year

All 1996 2.19 (1.84, 2.60)

1997 2.22 (1.90, 2.59)

1998 1.95 (1.66, 2.30)

1999 1.98 (1.68, 2.34)

2000 2.17 (1.86, 2.53)

2001 1.96 (1.69, 2.28)

2002 1.55 (1.32, 1.83)

2003 1.69 (1.45, 1.98)

2004 1.59 (1.35, 1.86)

2005 1.87 (1.61, 2.17)

2006 1.66 (1.43, 1.93)

2007 1.78 (1.51, 2.09)

2008 1.28 (1.04, 1.58)

2009 1.52 (1.25, 1.84)

2010 1.43 (1.15, 1.79)

2011 1.00 (0.71, 1.41)

Core 1996 3.40 (2.86, 4.03)

1997 3.31 (2.82, 3.88)

1998 2.85 (2.40, 3.38)

1999 3.11 (2.63, 3.69)

2000 3.39 (2.89, 3.97)

2001 2.85 (2.44, 3.33)

2002 2.18 (1.84, 2.58)

2003 2.44 (2.08, 2.87)

2004 2.16 (1.83, 2.55)2005 2.73 (2.34, 3.18)

2006 2.06 (1.75, 2.44)

2007 2.42 (2.04, 2.87)

2008 1.76 (1.41, 2.20)

2009 1.98 (1.61, 2.42)

2010 1.85 (1.45, 2.36)

2011 1.00 (0.63, 1.58)

Sample 1996 0.56 (0.30, 1.06)

1997 0.97 (0.60, 1.55)

1998 0.80 (0.52, 1.22)

1999 0.57 (0.36, 0.91)2000 0.62 (0.40, 0.97)

2001 0.95 (0.64, 1.41)

2002 0.86 (0.54, 1.36)

2003 0.69 (0.43, 1.11)

2004 1.04 (0.70, 1.54)

2005 0.71 (0.45, 1.13)

2006 1.57 (1.13, 2.20)

2007 1.14 (0.77, 1.70)

2008 0.80 (0.48, 1.35)

2009 1.27 (0.81, 2.00)

2010 1.06 (0.64, 1.73)

2011 1.00 (0.60, 1.67)Models adjusted for reporter type (where appropriate), season and harvestingPopulation offset included in the model *Other than contact dermatitis


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Figure 9 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, other (than contact dermatitis) skin

0

0.5

1

1.5

2

2.5

3

3.5

4

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.5

1

1.5

2

2.5

3

3.5

4

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.5

1

1.5

2

2.5

3

3.5

4

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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37

3.2.3 WORK-RELATED RESPIRATORY DISEASE

The average annual percentage change in risk of work-related respiratory

disease, as reported by chest physicians to SWORD is shown in Table 14

whilst the relative rates by year are shown in Tables 15 to 20 and Figures 10to 15.

For total respiratory disease, the graphs showing relative rates by year

suggest a slight increase in incidence between 2010 and 2011 (although

confidence intervals are overlapping for the two years) with the overall

average annual percentage decrease in incidence reducing slightly from

-3.6% reported upon last year for the period 1999-2010 to -3.3% (95% CIs:

-4.2,-2.4) for the period 1999-2011, with little variation between core and

sample reporters.

As observed previously, the annual average decrease in the incidence of

asthma was greater than that observed for total respiratory disease at -7.7%

(95% CIs: -9.2, -6.2) with a sharper decline observed for sample compared to

core reporters. Similarly, the addition of the 2011 case reports had little impact

on the overall observed trends for the other respiratory diagnoses investigated

with a smaller (than asthma), but still significant downward trend in the

incidence of mesothelioma (annual average decrease of -2.8% (95% CIs:

-4.4,-1.1), and relatively flat trends for benign pleural plaques,

pneumoconiosis and other respiratory disease (which includes rhinitis,

allergic alveolitis, lung cancer, inhalation accidents and other respiratory

diagnoses not already specified) over the study period.


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Table 14 Average annual percentage change in reported incidence inwork-related respiratory disease

a) All reporters

ESTIMATED % CHANGE

(95% CONFIDENCEINTERVAL)

Year (continuous) SWORD

Total respiratory 1999-2011 -3.3 (-4.2, -2.4)

Asthma 1999-2011 -7.7 (-9.2, -6.2)

Mesothelioma 1999-2011 -2.8 (-4.4, -1.1)

Benign pleural plaques 1999-2011 -0.7 (-2.0, 0.6)

Pneumoconiosis 1999-2011 -0.3 (-2.9, 2.3)Other* respiratory disease 1999-2011 0.5 (-1.5, 2.6)

b) Core reporters




Asthma 1999-2011 -7.4 (-9.0, -5.7)

Mesothelioma 1999-2011 -1.6 (-4.0, 0.8)

Benign pleural plaques 1999-2011 -1.7 (-3.2, -0.1)

Pneumoconiosis 1999-2011 0.7 (-2.4, 3.9)Other* respiratory disease 1999-2011 0.3 (-2.1, 2.8)

c) Sample reporters




Asthma 1999-2011 -9.1 (-12.7, -5.3)

Mesothelioma 1999-2011 -4.0 (-6.3, -1.6)

Benign pleural plaques 1999-2011 1.8 (-0.8, 4.5)

Pneumoconiosis 1999-2011 -3.2 (-7.8, 1.7)Other* respiratory disease 1999-2011 1.1 (-2.8, 5.2)


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39

Table 15 Relative rates by year, with 95% comparison intervals, totalrespiratory disease (2011 estimate =1)


SWORD

Reporter Group Year

All 1999 1.35 (1.23, 1.47)

2000 1.30 (1.19, 1.41)

2001 1.28 (1.17, 1.39)

2002 1.31 (1.20, 1.43)

2003 1.30 (1.20, 1.42)

2004 1.22 (1.12, 1.33)

2005 1.16 (1.06, 1.27)

2006 1.07 (0.98, 1.18)

2007 0.94 (0.85, 1.05)

2008 1.01 (0.91, 1.13)

2009 0.96 (0.86, 1.07)

2010 0.92 (0.82, 1.04)

2011 1.00 (0.89, 1.12)

Core 1999 1.35 (1.22, 1.50)

2000 1.34 (1.21, 1.48)

2001 1.37 (1.25, 1.51)

2002 1.44 (1.30, 1.59)

2003 1.47 (1.34, 1.61)

2004 1.36 (1.24, 1.50)

2005 1.22 (1.10, 1.34)

2006 1.10 (0.99, 1.22)

2007 0.92 (0.81, 1.05)

2008 1.00 (0.88, 1.14)

2009 0.94 (0.82, 1.09)

2010 0.95 (0.83, 1.10)2011 1.00 (0.87, 1.15)

Sample 1999 1.40 (1.19, 1.65)

2000 1.24 (1.05, 1.47)

2001 1.07 (0.89, 1.29)

2002 1.03 (0.85, 1.24)

2003 0.89 (0.73, 1.09)

2004 0.87 (0.71, 1.06)

2005 1.08 (0.90, 1.28)

2006 1.05 (0.88, 1.26)

2007 0.99 (0.82, 1.19)

2008 1.01 (0.84, 1.22)2009 0.98 (0.80, 1.19)

2010 0.84 (0.68, 1.05)2011 1.00 (0.81, 1.23)

Models adjusted for reporter type (where appropriate), season and harvestingPopulation offset included in the model


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Figure 10 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total respiratory disease

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year

SWORD, all reporters

0

0.2

0.40.6

0.8

1

1.2

1.4

1.6

1.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

R

elativerate

Year

SWORD, core reporters

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year

SWORD, sample reporters


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Table 16 Relative rates by year, with 95% comparison intervals,asthma (2011 estimate =1)


SWORD

Reporter Group Year

All 1999 2.56 (2.21, 2.98)

2000 1.92 (1.64, 2.26)

2001 2.04 (1.74, 2.38)

2002 2.10 (1.78, 2.48)

2003 2.06 (1.74, 2.43)

2004 1.92 (1.61, 2.29)

2005 1.72 (1.43, 2.07)

2006 1.63 (1.37, 1.94)

2007 1.13 (0.91, 1.40)

2008 1.21 (0.98, 1.49)

2009 0.93 (0.73, 1.18)

2010 0.95 (0.75, 1.22)

2011 1.00 (0.78, 1.28)

Core 1999 2.34 (1.97, 2.77)

2000 1.74 (1.45, 2.09)

2001 2.02 (1.71, 2.39)

2002 2.09 (1.75, 2.50)

2003 2.09 (1.75, 2.50)

2004 1.97 (1.64, 2.38)

2005 1.69 (1.38, 2.07)

2006 1.51 (1.25, 1.84)

2007 1.08 (0.85, 1.36)

2008 1.13 (0.90, 1.43)

2009 0.89 (0.68, 1.16)

2010 0.90 (0.69, 1.18)2011 1.00 (0.77, 1.31)

Sample 1999 4.53 (3.26, 6.30)

2000 3.33 (2.28, 4.85)

2001 2.10 (1.30, 3.40)

2002 2.19 (1.36, 3.54)

2003 1.79 (1.08, 2.98)

2004 1.54 (0.89, 2.67)

2005 2.04 (1.28, 3.25)

2006 2.65 (1.70, 4.13)

2007 1.58 (0.91, 2.74)

2008 1.89 (1.13, 3.17)2009 1.21 (0.62, 2.33)

2010 1.44 (0.77, 2.70)2011 1.00 (0.47, 2.12)



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Figure 11 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, asthma

0

1

2

3

4

5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

1

2

3

4

5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

R

elativerate

Year


0

1

2

3

4

5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 17 Relative rates by year, with 95% comparison intervals,mesothelioma (2011 estimate =1)


SWORD

Reporter Group Year

All 1999 1.40 (1.19, 1.65)

2000 1.41 (1.21, 1.65)

2001 1.40 (1.20, 1.64)

2002 1.39 (1.18, 1.63)

2003 1.34 (1.14, 1.57)

2004 1.18 (1.01, 1.39)

2005 1.04 (0.87, 1.24)

2006 1.04 (0.87, 1.25)

2007 1.32 (1.09, 1.61)

2008 1.30 (1.06, 1.59)

2009 1.16 (0.93, 1.45)

2010 1.08 (0.86, 1.36)

2011 1.00 (0.78, 1.28)

Core 1999 1.15 (0.92, 1.43)

2000 1.28 (1.05, 1.56)

2001 1.26 (1.03, 1.53)

2002 1.28 (1.05, 1.56)

2003 1.27 (1.05, 1.55)

2004 1.16 (0.96, 1.41)

2005 0.96 (0.77, 1.19)

2006 1.02 (0.81, 1.29)

2007 1.15 (0.87, 1.52)

2008 1.47 (1.12, 1.94)

2009 1.22 (0.91, 1.63)

2010 1.03 (0.75, 1.41)2011 1.00 (0.72, 1.39)

Sample 1999 1.75 (1.36, 2.24)

2000 1.56 (1.20, 2.02)

2001 1.58 (1.22, 2.05)

2002 1.48 (1.12, 1.95)

2003 1.34 (1.01, 1.77)

2004 1.10 (0.81, 1.49)

2005 1.13 (0.84, 1.51)

2006 1.04 (0.76, 1.42)

2007 1.54 (1.18, 2.00)

2008 1.12 (0.82, 1.51)2009 1.11 (0.80, 1.54)

2010 1.17 (0.84, 1.62)2011 1.00 (0.69, 1.45)



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Figure 12 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, mesothelioma

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.40.6

0.8

1

1.2

1.4

1.6

1.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

R

elativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 18 Relative rates by year, with 95% comparison intervals (2011estimate =1), benign pleural plaques


SWORD

Reporter Group Year

All 1999 0.92 (0.80, 1.06)

2000 1.10 (0.98, 1.25)

2001 1.07 (0.94, 1.21)

2002 1.09 (0.95, 1.24)

2003 1.14 (1.02, 1.29)

2004 1.03 (0.92, 1.16)

2005 1.09 (0.98, 1.22)

2006 0.95 (0.84, 1.08)

2007 0.88 (0.76, 1.02)

2008 0.94 (0.81, 1.10)

2009 0.89 (0.75, 1.05)

2010 1.01 (0.86, 1.18)

2011 1.00 (0.85, 1.18)

Core 1999 0.98 (0.84, 1.14)

2000 1.21 (1.05, 1.39)

2001 1.23 (1.08, 1.40)

2002 1.24 (1.08, 1.43)

2003 1.30 (1.14, 1.48)

2004 1.15 (1.01, 1.31)

2005 1.14 (1.01, 1.29)

2006 0.92 (0.80, 1.06)

2007 0.89 (0.75, 1.06)

2008 0.89 (0.74, 1.07)

2009 0.88 (0.72, 1.08)

2010 1.06 (0.88, 1.29)2011 1.00 (0.82, 1.22)

Sample 1999 0.95 (0.70, 1.27)

2000 0.92 (0.69, 1.24)

2001 0.67 (0.48, 0.95)

2002 0.72 (0.51, 1.02)

2003 0.74 (0.53, 1.02)

2004 0.77 (0.56, 1.05)

2005 1.17 (0.92, 1.49)

2006 1.18 (0.92, 1.52)

2007 0.89 (0.67, 1.19)

2008 1.09 (0.84, 1.41)2009 0.91 (0.68, 1.23)

2010 0.88 (0.64, 1.20)2011 1.00 (0.74, 1.36)



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Figure 13 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, benign pleural plaques

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.40.6

0.8

1

1.2

1.4

1.6

1.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

R

elativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 19 Relative rates by year, with 95% comparison intervals,pneumoconiosis (2011 estimate =1)


SWORD

ReporterGroup

Year

All 1999 0.84 (0.66, 1.06)

2000 0.79 (0.62, 1.00)

2001 0.74 (0.58, 0.94)

2002 0.65 (0.50, 0.85)

2003 0.70 (0.54, 0.89)

2004 0.56 (0.42, 0.74)

2005 0.68 (0.54, 0.87)

2006 0.77 (0.60, 0.98)

2007 0.53 (0.38, 0.74)

2008 0.69 (0.50, 0.95)

2009 0.84 (0.62, 1.15)

2010 0.67 (0.48, 0.95)

2011 1.00 (0.75, 1.33)

Core 1999 0.74 (0.56, 0.98)

2000 0.78 (0.61, 1.02)

2001 0.67 (0.51, 0.89)

2002 0.70 (0.52, 0.94)

2003 0.74 (0.57, 0.96)

2004 0.64 (0.48, 0.85)

2005 0.69 (0.52, 0.91)

2006 0.80 (0.62, 1.05)

2007 0.47 (0.31, 0.71)

2008 0.68 (0.47, 0.98)

2009 0.89 (0.63, 1.27)

2010 0.75 (0.51, 1.11)

2011 1.00 (0.71, 1.41)

Sample 1999 1.31 (0.84, 2.03)

2000 0.78 (0.44, 1.38)

2001 1.04 (0.63, 1.71)

2002 0.41 (0.18, 0.92)

2003 0.47 (0.22, 0.99)

2004 0.23 (0.08, 0.60)

2005 0.68 (0.38, 1.22)

2006 0.64 (0.35, 1.17)

2007 0.66 (0.37, 1.18)2008 0.71 (0.39, 1.29)

2009 0.70 (0.37, 1.30)

2010 0.43 (0.20, 0.96)2011 1.00 (0.58, 1.73)



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Figure 14 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, pneumoconiosis

0

0.5

1

1.5

2

2.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.5

1

1.5

2

2.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

R

elativerate

Year


0

0.5

1

1.5

2

2.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 20 Relative rates by year, with 95% comparison intervals,other* respiratory disease (2011 estimate =1)


SWORD

Reporter Group Year

All 1999 0.92 (0.72, 1.18)

2000 0.90 (0.71, 1.14)

2001 0.93 (0.73, 1.17)

2002 1.02 (0.80, 1.29)

2003 0.97 (0.77, 1.22)

2004 1.12 (0.92, 1.38)

2005 0.81 (0.64, 1.03)

2006 1.07 (0.87, 1.32)

2007 0.77 (0.60, 1.00)

2008 1.07 (0.84, 1.36)

2009 1.22 (0.98, 1.52)

2010 0.81 (0.61, 1.07)

2011 1.00 (0.78, 1.29)

Core 1999 1.14 (0.86, 1.51)

2000 1.01 (0.76, 1.34)

2001 1.04 (0.78, 1.38)

2002 1.29 (0.98, 1.70)

2003 1.24 (0.96, 1.59)

2004 1.42 (1.14, 1.78)

2005 0.98 (0.75, 1.28)

2006 1.40 (1.11, 1.76)

2007 0.93 (0.69, 1.26)

2008 1.35 (1.03, 1.77)

2009 1.42 (1.09, 1.85)

2010 1.08 (0.79, 1.46)2011 1.00 (0.72, 1.39)

Sample 1999 0.53 (0.32, 0.88)

2000 0.68 (0.43, 1.06)

2001 0.72 (0.47, 1.13)

2002 0.52 (0.31, 0.87)

2003 0.52 (0.31, 0.88)

2004 0.62 (0.39, 0.98)

2005 0.52 (0.32, 0.87)

2006 0.50 (0.30, 0.83)

2007 0.49 (0.29, 0.81)

2008 0.59 (0.36, 0.96)2009 0.82 (0.54, 1.25)

2010 0.36 (0.19, 0.69)2011 1.00 (0.65, 1.53)

Models adjusted for reporter type (where appropriate), season and harvestingPopulation offset included in the model*Other than those specified above


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Figure 15 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, other respiratory disease

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year


0

0.2

0.40.6

0.8

1

1.2

1.4

1.6

1.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

R

elativerate

Year


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Relativerate

Year



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3.2.4 WORK-RELATED MUSCULOSKELETAL DISORDERS

The average annual percentage change in reported incidence of work-related

musculoskeletal disorders (MSDs), as reported by GPs (THOR-GP) is shown

in Table 21 whilst the relative rates by year are shown in Tables 22 to 25 and

Figures 16 to 19. Data from GPs suggested a downward trend in the

incidence of total work-related MSDs in the order of -15.4% (95% CIs: -18.6,

-12.0) per year. For comparison, the annual average decrease based on data

for 2006-2010 was -15.2% (95% CIs: -18.5, -11.6). The pattern for upper limb

disorders was very similar to that observed for total MSDs, whilst for

spine/back disorders generally a steeper annual decrease was observed. A

downward trend in the incidence of lower limb disorders was also observed

(although this was not statistically significant). The graphs showing relativerates by year show a sharp drop in incidence for THOR-GP between 2006

and 2007 with rates continuing to fall thereafter.

Table 21 Average annual percentage change in reported incidence inwork-related musculoskeletal disorders


Reportergroup

Year (continuous) THOR-GP

All Total musculoskeletal 2006-2011 -15.4 (-18.6, -12.0)

Upper limb 2006-2011 -15.2 (-19.5, -10.7)

Spine/back 2006-2011 -19.2 (-24.1, -14.1)Lower limb 2006-2011 -8.7 (-17.4, 0.9)


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Table 22 Relative rates by year, with 95% comparison intervals, totalmusculoskeletal disorders (2011 estimate = 1)

Relative rates (95% comparisoninterval)

Reporter Group THOR-GP

All 2006 2.51 (2.27, 2.78)

2007 1.85 (1.69, 2.03)

2008 1.74 (1.57, 1.92)

2009 1.47 (1.33, 1.63)

2010 1.27 (1.07, 1.52)2011 1.00 (0.77, 1.31)


Figure 16 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total musculoskeletal disorders

0

0.5

1

1.5

2

2.5

3

3.5

4

2006 2007 2008 2009 2010 2011

Relativerate

Year

THOR-GP, all reporters


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Table 23 Relative rates by year, with 95% comparison intervals,upper limb disorders (2011 estimate = 1)

Relative rates (95% comparisoninterval)


All 2006 2.98 (2.58, 3.44)

2007 2.23 (1.95, 2.55)

2008 1.97 (1.70, 2.30)

2009 1.87 (1.61, 2.18)

2010 1.48 (1.20, 1.84)2011 1.00 (0.64, 1.56)


Figure 17 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, upper limb disorders

0

0.5

1

1.5

2

2.5

3

3.5

4

2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 24 Relative rates by year, with 95% comparison intervals,spine/back disorders (2011 estimate = 1)

Relative rates (95%comparison interval)


All 2006 2.68 (2.30, 3.14)

2007 2.01 (1.75, 2.30)

2008 1.86 (1.53, 2.26)

2009 1.30 (1.07, 1.58)

2010 1.27 (0.99, 1.63)2011 1.00 (0.63, 1.59)


Figure 18 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, spine/back disorders

0

0.5

1

1.5

2

2.5

3

3.5

4

2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 25 Relative rates by year, with 95% comparison intervals, lowerlimb disorders (2011 estimate = 1)


ReporterGroup

THOR-GP

All 2006 1.64 (1.22, 2.21)

2007 1.10 (0.83, 1.44)2008 1.27 (0.97, 1.66)

2009 1.16 (0.88, 1.54)

2010 0.99 (0.69, 1.43)2011 1.00 (0.48, 2.10)


Figure 19 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, lower limb disorders

0

0.5

1

1.5

2

2.5

3

3.5

4

2006 2007 2008 2009 2010 2011

Relativerate

Year



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3.2.5 WORK-RELATED MENTAL ILL-HEALTH

The average annual percentage change in reported incidence of work-related

mental ill-health, as reported by GPs (THOR-GP) is shown in Table 26 whilst

the relative rates by year are shown in Tables 27 to 29 and Figures 20 to 22.

Overall an average annual decrease in the incidence of total mental ill-health

was observed of -9.2% (95% CIs: -13.5, -4.7). This compared to a decrease of

-8.8% (95% CIs: -13.1, -4.1) observed previously (2006-2010). However, the

graphs showing relative rates by year suggest the previously observed

increase in incidence in 2010 has been followed by a decrease in incidence in

2011 (although it must be noted that the confidence intervals for the 2010 and

2011 estimates overlap the other years). A similar pattern was seen for

anxiety and depression, and other work stress.

Table 26 Average annual percentage change in reported incidence inwork-related mental ill-health

ESTIMATED % CHANGE(95% CONFIDENCE

INTERVAL)Reportergroup

Year (continuous) THOR-GP

All Total mental ill-health 2006-2011 -9.2 (-13.5, -4.7)

Anxiety and depression 2006-2011 -7.7 (-14.2, -0.6)Other work stress 2006-2011 -10.7 (-15.9, -5.2)


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Table 27 Relative rates by year, with 95% comparison intervals, totalmental ill-health (2011 estimate = 1)


ReporterGroup

THOR-GP

All 2006 1.43 (1.26, 1.63)

2007 1.29 (1.15, 1.45)2008 1.17 (1.02, 1.35)

2009 0.92 (0.79, 1.06)

2010 1.41 (1.21, 1.65)2011 1.00 (0.71, 1.40)


Figure 20 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, total mental ill-health

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2006 2007 2008 2009 2010 2011

Relativerate

Year



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Table 28 Relative rates by year, with 95% comparison intervals,anxiety and depression (2011 estimate = 1)


ReporterGroup

THOR-GP

All 2006 1.54 (1.26, 1.87)

2007 1.46 (1.22, 1.73)2008 1.21 (1.00, 1.48)

2009 1.08 (0.88, 1.33)

2010 1.68 (1.29, 2.19)2011 1.00 (0.63, 1.59)


Figure 21 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, anxiety and depression

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2006 2007 2008 2009 2010 2011

Re

lativerate

Year



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Table 29 Relative rates by year, with 95% comparison intervals, otherwork stress (2011 estimate = 1)


ReporterGroup

THOR-GP

All 2006 1.36 (1.16, 1.60)

2007 1.18 (1.02, 1.36)2008 1.16 (1.00, 1.35)

2009 0.81 (0.68, 0.96)

2010 1.16 (0.93, 1.44)2011 1.00 (0.70, 1.43)


Figure 22 Relative rates by year (2011 estimate = 1), with 95%comparison intervals, other work stress

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2006 2007 2008 2009 2010 2011

Relativerate

Year



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4 DISCUSSION

This is the latest report describing temporal trends in incidence of WRI as

reported by physicians to the THOR surveillance network. For the current

report, data from NHS hospital based specialist consultants reporting to

EPIDERM (skin) and SWORD (respiratory), and from GPs reporting to THOR-

GP (all WRI) were used to estimate trends for the period 1996-2011

(EPIDERM), 1999-2011 (SWORD) and 2006-2011 (THOR-GP). HSE funding

for data collection for the other main extant THOR scheme, OPRA

(occupational physicians), ceased at the end of 2010, with trends for that

period (2006-2010) reported upon previously2.

There have been no changes to the methodology reported on here in respect

of trends calculations since the 2011 trends report was submitted and

changes made at that point and earlier are discussed in full in previous

reports2-7. However, one important issue that was discussed in the 2011

report that warrants further comment here was the substantial change to the

THOR-GP sampling methodology, which moved from >90% core (reporting on

a monthly basis) prior to 2010 to 78% sample (reporting one randomly chosen

month per year) in 2010. By way of background it should be restated thatwhen THOR-GP was launched in 2005 it started generating reports at a far

higher level than specified in the contract (so as to pump prime the database).

The data collection in 2010 was as per the original contract. Moreover, since

HSE funding was limited, the participating GPs were then no longer paid an

honorarium for these reports. Therefore, for the present round of analyses, a

further shift occurred with 100% of the GPs reporting in 2011 reporting on a

sample basis. Initial investigations of case reporting in THOR-GP suggestedthat physicians reporting as sample in 2010 and 2011 reported, on average,

three times as many cases (in any one month) than when reporting as core

reporters in 2009. Work is currently underway to investigate this rate

difference between core and sample. We had previously reported the same

phenomenon with OPRA11 but with a much smaller magnitude. One

hypothesis that has been put forward is that some of the cases reported by

GPs might not be truly incident. It is likely that a patient will make more

frequent visits to the GP than to other physicians, possibly for further sickness


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certification. Therefore a GP may report a case in their reporting month that

they first saw in clinic with the same problem in a previous month (i.e.

harvesting). This would produce an overestimate in rates as such a case is

prevalent, rather than incident. This is more likely to happen for those only

reporting one month a year (sample) compared to continuous (core) reporters.

However, further work is required to understand this issue fully.

As discussed previously2the approach adopted in the MLM analyses was to

treat a physician as a new reporter if they changed from core to sample (or

vice versa). GPs reporting for the first time as sample reporters in 2010 would

therefore only have two data points and those reporting as sample for the first

time in 2011 would only have one data point and would therefore (in theory)

contribute less to the overall trend. Analyses reported upon previously for the

period 2006-2010 did appear to confirm this with estimates from the THOR-

GP MLM in which sample data were excluded being very similar to those in

which all data were included. Core reporting stopped at the end of 2010 so

this exercise was not repeated in the current round of analyses. It would also

be informative to investigate trends based on sample data only but at present

numbers are too small to yield any meaningful results (63% of sample

reporters have two data points, with a further 30% having one data point only).In view of the small numbers and until the issue of change in time sampling

pattern is more fully understood, the THOR-GP trend estimates need to be

interpreted with caution.

THOR trends methodology has progressively addressed relevant artefacts

(e.g. changing denominators). The main residual issue which has been much

discussed within the trends project is the issue of reporter fatigue. Initialinvestigations primarily focussed on determining whether the proportion of

responses that are zero returns (i.e. declaring I have nothing to report) or the

proportion of non-response had increased over time (both of which could be

an indication of reporter fatigue)12, 13. In brief, for the specialist schemes,

results suggested some evidence that the proportion of both non-response

and zero returns increased with membership time, whilst for THOR-GP, the

proportion of zero returns but not non-response increased with membership

time. Following this it was recognised that further work in this area was


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required, and as such, additional HSE funding was secured to address this

and other issues relating to THOR trends and incidence. This comprised 6

work packages, 2 of which related to specifically to the issue of fatigue14-16.

The first of these built on the earlier work investigating changes in the

probability of a zero-return or non-response over time. The other work

package relevant to this issue investigated whether there was evidence of

fatigue manifesting as an excess of zeros in the THOR data and if so, how

this could best be modelled. The results suggested evidence of zero-inflation

in some schemes/reporter groups (in EPIDERM both core and sample

reporters and in OPRA sample reporters only) but not others (THOR-GP,

SWORD, and OPRA core reporters). However, an excess of zeros would only

impact on the trends analysis if there was further evidence that the

percentage of false zeros changed over time and such evidence was found for

EPIDERM sample reporters only.

As in previous reports, the estimates presented here have not been adjusted

for the potential effects of fatigue. The latest body of work regarding this issue

has only fairly recently been completed, with the findings and their

implications for future analyses still under discussion within the THOR team

and in the THOR steering group. However, it is planned that the 2013 trendsreport will provide further updates regarding this issue.

An abridged commentary by category of illness is provided in the following

sections.

SKIN (EPIDERM and THOR-GP): The primary source of THOR data of work-

related skin disease is reports from dermatologists to EPIDERM, with trendsin incidence for this group first described in a report submitted to HSE in

20057. Overall, the addition of each successive year of data has not greatly

affected the estimated average annual change in incidence of total work-

related skin disease which has remained at around a 3% decrease per year.

However, the plots showing relative rates have suggested some variation in

incidence between years. Most notable in the current round of analyses was

the relatively large drop in incidence between 2010 and 2011 compared to

changes between other years. This may reflect (at least in part) changes in


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reporting methods between the two years and has therefore to be treated very

cautiously. Prior to 2011, dermatologists could submit their case reports to

EPIDERM using either the traditional paper based report card (which would

be sent to them in the post prior to their reporting month) or electronically via a

web form. For 2011 however, it was decided not to send the report card in the

post as usual but to instead email the physicians an electronic version of the

card which they could then complete and return (with the option to report via a

web form also still available). This was both an attempt to increase the

proportion of physicians reporting electronically (with the obvious benefits of

reducing transcription errors etc) and of reducing the costs incurred through

the printing and postage of the traditional report cards (HSE funding for 2011

EPIDERM data collection had not been secured at the time). However,

response rates for 2011 were notably lower than in previous years, particularly

for core reporters, and feedback from the physicians suggested that they

found the traditional report cards much more practical for their day to day

practice. In view of this, the cards were reinstated for reporting in 2012.

The trend in incidence observed for dermatologist reported contact dermatitis

(CD) was very similar to that observed for skin overall, unsurprising given that

case reports of CD comprise the majority of the skin reports. The largerdecrease in incidence observed for allergic CD compared to irritant CD has

been discussed in previous reports2,3with the suggestion that it may reflect

steps such as the reduction in use of powdered latex gloves following

Government interventions (introduced between 1996 and 1998) aiming to

reduce exposure to latex. This theory is further corroborated by the observed

change in the incidence of (dermatologist reported) contact urticaria (CU)

(which would also be expected to decrease if the latex interventions weresuccessful) which shows a decline over a similar period. Indeed, as the quality

and quantity of the data increases, it has been possible for THOR to apply the

trends methodology to investigate the impact of Government (or other)

interventions aiming to reduce the incidence of WRI attributed to specific

agents such as latex and chromium17, 18.

The other main sub-group of skin diagnoses reported by dermatologists to

EPIDERM was neoplasia, for which a smaller (compared to CD and CU), but


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still statistically significant, annual decrease in incidence was observed.

However, there was a large drop in the number of case reports of neoplasia

(particularly from core physicians) in 2011 compared to previous years,

reflected in the results by the wide confidence intervals around the 2011

estimate. This drop in 2011 may partly reflect the overall decline in response

rates arising from the cessation of the paper based report card. However,

different trends have been observed between reporter type (core and sample)

previously2, with core data suggesting a decrease in incidence and sample

data suggesting an increase in incidence. This may be because core

EPIDERM reporters main area of expertise has historically been and probably

still is in occupational contact dermatitis, so skin neoplasia referrals may be

triaged to other (sample) reporters.

A decrease in the incidence of GP reported work-related skin disease was

also observed which, although not statistically significant, was larger than that

seen for dermatologists over the same time period. However, skin reports

comprise a relatively small proportion of the total cases reported to THOR-GP,

and this coupled with the (as yet unknown) impact on the trend estimate of the

previously discussed changes in sampling frequency (i.e. the move from

predominantly core to predominantly sample), means it is important to becautious when interpreting the trend estimates for THOR-GP.

RESPIRATORY (SWORD): Trends in incidence based on data from

respiratory physicians have also been described since the initial report

submitted to HSE in 20067. Compared to dermatologists however, the addition

of each successive year of data appears to have had more of an impact on

the annual average estimated change in incidence of total work-relatedrespiratory disease from an initial decrease of around 1% per year (based on

data for the period 1999-2004) to a decrease of around 3% observed in the

current round of analyses. The greater variability (compared to skin) may

reflect differences in case mix (and changes in case mix over time) between

the two groups of reporters. Whilst case reports to EPIDERM are

predominantly CD and neoplasia (and have been throughout the study

period), case reports to SWORD encompass a wider diagnostic range with the

proportion of the total cases attributed to each diagnosis exhibiting some


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variation throughout the study period. Therefore, for respiratory disease (as

reported by chest physicians), it is probably more informative to look at

changes in incidence for the individual respiratory sub-groups.

Regarding asthma, the average annual percentage change in reported

incidence has remained at about a 7% decrease per year with much of this

decrease appearing to have been driven by a fall in incidence in earlier years,

with a relatively flat trend apparent since 2007. As observed for skin disease,

this decrease in incidence may, in part, reflect the introduction of Government

(and other) initiatives targeting this disease category. Recent work has begun

to investigate the impact of changes in legislation, regulatory activity and

market forces on the incidence of workplace asthma in the UK19.

In addition to asthma, changes in the incidence of the (primarily) asbestos

related diseases, namely, mesothelioma, benign pleural plaques and

pneumoconiosis were also (separately) investigated. For all three groups, an

overall decrease in incidence was observed (but this was only statistically

significant for mesothelioma). The reported decline in the incidence of

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Thor Trends 12

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