Harvard University Initiative for Global Health

Global Health ChallengesSocial Analysis 76: Lecture 20

Harvard University Initiative for Global Health

Attributable Disease Burden of 20 Risk Factors

0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0%

Underw eight

Unsafe sex

High blood pressure

Tobacco

Alcohol

Unsafe w ater, sanitation, and hygiene

High cholesterol

Indoor smoke from solid fuels

Iron deficiency

High BMI

Zinc deficiency

Low fruit and vegetable intake

Vitamin A deficiency

Physical inactivity

Occupational risk factors for injury

Lead exposure

Illicit drugs

Unsafe health care injections

Lack of contraception

Childhood sexual abuse

Attributable DALY (% of global DALY - Total 1.46 billion)

High-mortality developing

Lower-mortality developing

Developed

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Iron Deficiency Anaemia

Vitamin A Deficiency

Zinc Deficiency

Review of Diseases, Injuries and Risk Factors

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Odds Ratio Estimate.3 .5 .75 1 1.1

Combined

UK86

PNG99

Nigeria85

Nigeria82

Nigeria75

Nepal98

Malaysia65

Kenya63

India95

China96

Summary OR: 0.72

Perinatal mortality: OR’s for each 1 g/dL Hb increase

From Stoltzfus et al, 2005

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Prevalence of anaemia among children 0 – 4 years old by CRA region

5 - 1616 - 2828 - 3939 - 5151 - 63

Prevalence (%)

From Stoltzfus et al, 2005

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Global DALYs From Iron Deficiency

56%

10%

34% Perinatal Causes

Maternal Causes

Iron DeficiencyAnemia

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DALYs from Perinatal Conditions, Maternal Conditions and Iron Deficiency Anaemia, Attributable to Iron

Deficiency, by Subregion (000s)

AFR-D

AFR-E

AMR-B

EUR-A

SEAR-D

WPR-A

WPR-B

EMR-D

EUR-BEUR-C

SEAR-B

EMR-BAMR-D

AMR-A

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Effect of Iron/Folic Acid (IFA) Supplementation on Adverse Events in

Children 1-48 Months Old

• Nepal (19,299 child-years IFA, 9,799 placebo) – no effect on deaths1

• Zanzibar (16,950 child-years IFA, 8,574 placebo) – 12% increase in all hospitalizations/deaths, 16% in malaria, 33% in pneumonia2

1Tielsch et al, submitted2Sazawal et al, submitted

Harvard University Initiative for Global Health

Effect of Iron/Folic Acid Supplementation on Adverse Events (Hospitalization and Death)

in Children in Zanzibar (following 16,950 child-years in supplemented and 8,574 in

placebo groups)

OutcomeRelative

Risk 95% CI

All 1.12 1.02 – 1.23

Malaria 1.16 1.02 – 1.32

Cerebral malaria 1.22 1.02 – 1.46

Pneumonia 1.33 1.07 – 1.65

Other infections 1.32 1.10 – 1.59

From Sazawal et al, submitted

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Iron Deficiency Anaemia

Vitamin A Deficiency

Zinc Deficiency

Review of Diseases, Injuries and Risk Factors

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Effects of Vitamin A on Infectious Disease Morbidity

• Possible effect on diarrhea severity, but not all morbidity

• No effect on pneumonia morbidity

• Effect on measles complications

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Prevalence of vitamin A deficiency among children 0-4 years old by CRA regions

From West et al., 2002

0 - 1010 - 1919 - 2929 - 3838 - 48

Prevalence (%)

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Major Trials of Vitamin A to Prevent Mortality

Over 165,000 children participated in these 8 trials

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Vitamin A Implementation

• Widespread implementation of Vitamin A supplementation often linked to immunization programs.

• Is coverage sustainable outside of immunization campaigns?

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Iron Deficiency Anaemia

Vitamin A Deficiency

Zinc Deficiency

Review of Diseases, Injuries and Risk Factors

Harvard University Initiative for Global Health

Harvard University Initiative for Global Health

Global Zinc Deficiency

0 – 14.9 % Deficient 15 – 24.9 % Deficient > 25 % Deficient

From Brown et al, 2004

Harvard University Initiative for Global Health

Preventive Effect of Zinc Supplementation on Diarrheal Prevalence in Continuous

Supplementation Trials B.Faso

IndiaMexico

PNGPeru

VietnamEthopia

GuatemalaJamaica

Pooled

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2

Odds Ratio and 95% CI

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Preventive Effect of Zinc Supplementation on Pneumonia Incidence in Continuous

Supplementation Trials

3

India(S)

Peru

Vietnam

Jamaica

India(B)

Pooled

0 0.5 1 1.5 2 2.5

Relative Risk and 95% CI

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Effect of Zinc Supplementation on Malaria in Children

LocationReduction in Clinic Visits for Malaria

The Gambia1 32% (p=0.09)

Papua New Guinea2

38% (p<0.05)

Combined 36% (CI 9-55%, p<0.05)

1Bates et al, Brit J Nutr, 19932Shankar et al, Am J Trop Med Hyg, 2000

Harvard University Initiative for Global Health

Trial in Bangladesh Evaluating the Preventive Effect of

Weekly Zinc Supplementation

• 1-23 mo. old children, weekly zinc (70 mg)

• 6% less diarrhea, 17% less pneumonia, 49% less severe pneumonia and 42% less otitis media,

• 85% less mortality

From Brooks et al, Lancet 2005

Harvard University Initiative for Global Health

Efficacy Trials of Zinc Supplementation on Child Mortality

• Zanzibar and Nepal

• Children 1-35 mo. old (>60,000 child-years)

• Randomized, controlled trials

• Daily 10 mg zinc (5 mg if <12 mo old)

• All children receive vitamin A

• Trial to be completed in Zanzibar in September 2005 and Nepal in January 2006

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Iron Deficiency Anaemia

Vitamin A Deficiency

Zinc Deficiency

Review of Diseases, Injuries and Risk Factors

Harvard University Initiative for Global Health

Leading Causes of the Global Burden of Disease 2002

1. Perinatal conditions 6.5

2. Lower respiratory infections 6.1

3. HIV/AIDS 5.7

4. Depression 4.5

5. Diarrhoeal diseases 4.2

6. Ischaemic heart disease 3.9

7. Cerebrovascular disease 3.3

8. Malaria 3.1

9. Road traffic accidents 2.6

10. Tuberculosis 2.3

DALYs%

Source: World Health Report, 2004Source: World Health Report, 2004

Harvard University Initiative for Global Health

Attributable Disease Burden of 20 Risk Factors

0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0%

Underw eight

Unsafe sex

High blood pressure

Tobacco

Alcohol

Unsafe w ater, sanitation, and hygiene

High cholesterol

Indoor smoke from solid fuels

Iron deficiency

High BMI

Zinc deficiency

Low fruit and vegetable intake

Vitamin A deficiency

Physical inactivity

Occupational risk factors for injury

Lead exposure

Illicit drugs

Unsafe health care injections

Lack of contraception

Childhood sexual abuse

Attributable DALY (% of global DALY - Total 1.46 billion)

High-mortality developing

Lower-mortality developing

Developed

Harvard University Initiative for Global Health

What diseases, injuries or risk factors are What diseases, injuries or risk factors are missing from these lists?missing from these lists?

What is Missing?