A longitudinal analysis of physical activity and overweight/obesity in adolescents in Saskatoon Hang Lai 1 , Nazeem Muhajarine 2 , Karen Chad 3 1, 2 Dept. of Community Health and Epidemiology, University of Saskatchewan; and 3 College of Kinesiology, University of Saskatchewan. - PowerPoint PPT Presentation
1 A longitudinal analysis of physical activity A longitudinal analysis of physical activity and overweight/obesity in adolescents in and overweight/obesity in adolescents in Saskatoon Saskatoon Hang Lai Hang Lai 1 , Nazeem Muhajarine , Nazeem Muhajarine 2 , Karen Chad , Karen Chad 3 1, 2 1, 2 Dept. of Community Health and Epidemiology, University Dept. of Community Health and Epidemiology, University of Saskatchewan; of Saskatchewan; and and 3 College of Kinesiology, University of Saskatchewan College of Kinesiology, University of Saskatchewan
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A longitudinal analysis of physical activity and A longitudinal analysis of physical activity and overweight/obesity in adolescents in Saskatoonoverweight/obesity in adolescents in Saskatoon
1, 21, 2 Dept. of Community Health and Epidemiology, University of Saskatchewan; Dept. of Community Health and Epidemiology, University of Saskatchewan;
and and 33 College of Kinesiology, University of Saskatchewan College of Kinesiology, University of Saskatchewan
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OutlineOutline
• Research Questions Research Questions • MethodologyMethodology• Results Results • DiscussionDiscussion• ImplicationsImplications• ConclusionConclusion
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Research QuestionsResearch Questions
1) How do physical activity and overweight/obesity change over time in 1) How do physical activity and overweight/obesity change over time in a cohort of adolescents in Saskatoon? Are there differences in the a cohort of adolescents in Saskatoon? Are there differences in the patterns of change in physical activity and overweight/obesity patterns of change in physical activity and overweight/obesity between boys and girls?between boys and girls?
2) What are the effects of family/friends and physical environments on 2) What are the effects of family/friends and physical environments on the changing patterns of physical activity in this sample? the changing patterns of physical activity in this sample?
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Methodology: (1) Study sampleMethodology: (1) Study sample
• The data used in this study was taken from the The data used in this study was taken from the in motionin motion studies’ longitudinal studies’ longitudinal data. data.
• The target population comprised 835 adolescents from 12 to18 years of ageThe target population comprised 835 adolescents from 12 to18 years of age
• From seven schools in Saskatoon (Bedford Road: 325; Evan Hardy: 244; Egnatoff: From seven schools in Saskatoon (Bedford Road: 325; Evan Hardy: 244; Egnatoff: 148; King George: 35; Caswell Hill: 39; Westmount: 15 and Mayfair: 29)148; King George: 35; Caswell Hill: 39; Westmount: 15 and Mayfair: 29)
• From six different school grade levels: grade 7 to grade 12From six different school grade levels: grade 7 to grade 12
• In February 2003, the survey was distributed through the schools to students.In February 2003, the survey was distributed through the schools to students.
• PA levels were assessed using the ‘My Physical Activity’ Questionnaire (Modifiable PA levels were assessed using the ‘My Physical Activity’ Questionnaire (Modifiable Activity Questionnaire for Adolescents - MAQ-A). The data collection was collected Activity Questionnaire for Adolescents - MAQ-A). The data collection was collected once per month from February to June 2003.once per month from February to June 2003.
• The ‘Factors Affecting My Physical Activity’ questionnaire was used to assess The ‘Factors Affecting My Physical Activity’ questionnaire was used to assess physical activity determinants. Data collection was collected in February and April physical activity determinants. Data collection was collected in February and April 2003.2003.
• The study outcome is Physical Activity, which is defined as high, moderate or low The study outcome is Physical Activity, which is defined as high, moderate or low level.level.
• KKD is used to assess physical activity level, defined as total daily energy KKD is used to assess physical activity level, defined as total daily energy expenditure (Kilocalories/kilogram of body weight/day – KKD).expenditure (Kilocalories/kilogram of body weight/day – KKD).
• Low PA (sedentary)Low PA (sedentary) <= 2 KKD<= 2 KKD
• Moderate PAModerate PA 2-8 KKD2-8 KKD
• High PA (enough physical High PA (enough physical >= 8 KKD >= 8 KKD
activity to achieve health benefits)activity to achieve health benefits)
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ResultsResults
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Factor analysis resultsFactor analysis results
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Proportion of overweight/obesity Proportion of overweight/obesity by sex and age at Time 1 & Time 3by sex and age at Time 1 & Time 3
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Proportion of PA levelsProportion of PA levels
Proportion of Physical activity levels in 5 time points
0
10
20
30
40
50
60
Time 1 Time 2 Time 3 Time 4 Time 5
%
Low
Mod
High
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Distributions of PA levels by gender and ageDistributions of PA levels by gender and age
Low PA distribution for female by time
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Time 1 Time 2 Time 3 Time 4 Time 5
12-14
15-16
17-18
Low PA distribution for male by time
0%
5%
10%
15%
20%
25%
30%
Time 1 Time 2 Time 3 Time 4 Time 5
12-14
15-16
17-18
Moderate PA distribution for female by time
0%
10%
20%
30%
40%
50%
60%
Time 1 Time 2 Time 3 Time 4 Time 5
12-14
15-16
17-18
Moderate PA distribution for male by time
0%
10%
20%
30%
40%
50%
60%
Time 1 Time 2 Time 3 Time 4 Time 5
12-14
15-16
17-18
High PA distribution for female by time
0%5%
10%15%20%25%30%35%40%45%
Time 1 Time 2 Time 3 Time 4 Time 5
12-14
15-16
17-18
High PA distribution for male by time
0%
10%
20%
30%
40%
50%
60%
70%
Time 1 Time 2 Time 3 Time 4 Time 5
12-14
15-16
17-18
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KKD distributionsKKD distributions
KKD distribution for adolescent girls and boys in 5 time points
-
2
4
6
8
10
12
Time 1 Time 2 Time 3 Time 4 Time 5
Girl
Boy
t = (-2.16/0.62)t = (-2.16/0.62) = -3.48= -3.48
p < 0.01p < 0.01
t = (-1.37/0.51) t = (-1.37/0.51) = -2.69= -2.69
p < 0.01p < 0.01
t = (-0.84/0.45) t = (-0.84/0.45) = -1.87= -1.87
p < 0.05p < 0.05
t = (-0.6/0.5) = t = (-0.6/0.5) =
-1.19-1.19
p > 0.05p > 0.05
t = (-0.45/0.49) t = (-0.45/0.49) = -0.92= -0.92
p > 0.05p > 0.05
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Final main effect model Final main effect model examining factors associated with High PAexamining factors associated with High PA
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Discussion Discussion (1)(1)
1) Patterns of PA and overweight/obesity over time1) Patterns of PA and overweight/obesity over time
• Among adolescent girls those who were PA decreased over time during the Among adolescent girls those who were PA decreased over time during the school year; correspondingly proportion of girls overweight/obese increased over school year; correspondingly proportion of girls overweight/obese increased over time.time.
• Among adolescent boys, the pattern of change observed over the school year in Among adolescent boys, the pattern of change observed over the school year in overweight/obesity prevalence and PA levels were not dependent on each other.overweight/obesity prevalence and PA levels were not dependent on each other.
• With age, level of physical activity declined for both boys and girls.With age, level of physical activity declined for both boys and girls.
• Gender differences in PA were consistent: Adolescent girls were significantly less Gender differences in PA were consistent: Adolescent girls were significantly less active than boys.active than boys.
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Discussion Discussion (2)(2)
2) Determinants of changing PA patterns2) Determinants of changing PA patterns
• Effects of Family & FriendsEffects of Family & Friends
• Adolescents who received greater direct support from family members were Adolescents who received greater direct support from family members were more likely to sustain their PA levels.more likely to sustain their PA levels.
• The more the family’s indirect support the less sustaining the adolescents’ PA The more the family’s indirect support the less sustaining the adolescents’ PA were.were.
• Friend’s support was not a significant variable in predicting adolescent PA over Friend’s support was not a significant variable in predicting adolescent PA over time.time.
• Effects of Physical EnvironmentsEffects of Physical Environments
• Home environment had a influence on sustaining physical activity among Home environment had a influence on sustaining physical activity among adolescent, and neighborhood environment had no impact on PA in adolescent, and neighborhood environment had no impact on PA in adolescents in this study. adolescents in this study.
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ImplicationsImplications
• Health promotion efforts should be aimed at reducing gender disparities in PA: high Health promotion efforts should be aimed at reducing gender disparities in PA: high
priority should be placed on developing effective interventions for adolescent girls.priority should be placed on developing effective interventions for adolescent girls.
• Interventions should be targeted to adolescent group to counter the decline in PA Interventions should be targeted to adolescent group to counter the decline in PA
levels.levels.
• More research is needed to improve understanding about the reason and mechanism More research is needed to improve understanding about the reason and mechanism
for the decline.for the decline.
• Family-based PA intervention program hold promise for long-term effectiveness Family-based PA intervention program hold promise for long-term effectiveness
Community actions should acknowledge the potential of families as PA promoting Community actions should acknowledge the potential of families as PA promoting
units, and the vital contributions of families to PA.units, and the vital contributions of families to PA.
• Households should be encouraged to provide safe spaces and facilities for physical Households should be encouraged to provide safe spaces and facilities for physical
activity that promote and enable adolescents and all family members to participate in activity that promote and enable adolescents and all family members to participate in
and enjoy physical activities.and enjoy physical activities.
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ConclusionConclusion
• The current investigation confirms findings from previous studies: The current investigation confirms findings from previous studies:
• Adolescent BMI increase with age, while PA decreased with age.Adolescent BMI increase with age, while PA decreased with age.
• Boys were more likely to be active than girls. Boys were more likely to be active than girls.
• Direct support from family and home environment had influence on sustaining Direct support from family and home environment had influence on sustaining
physical activity among adolescents. physical activity among adolescents.
• Contrary to some other studies, Contrary to some other studies,
• Indirect support from family was contributed to decrease adolescents’ PA.Indirect support from family was contributed to decrease adolescents’ PA.
• No association between friend’s support, neighborhood environment and No association between friend’s support, neighborhood environment and
adolescents’ PA were found in this study.adolescents’ PA were found in this study.
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AcknowledgementsAcknowledgements
• This research was supported by a grant from the Community and Population Health This research was supported by a grant from the Community and Population Health
Research (CPHR) Training Program delivered by the Saskatchewan Population Research (CPHR) Training Program delivered by the Saskatchewan Population
Health and Evaluation Research Unit (SPHERU).Health and Evaluation Research Unit (SPHERU).
• I gratefully acknowledge the support of the CPHR Training Program in my I gratefully acknowledge the support of the CPHR Training Program in my
presentation at the Conference.presentation at the Conference.
