The Quebec Child and Adolescent Health and Social Survey:: Design and methods of a cardiovascular risk factor survey for youth

BACKGROUND: Although atherosclerosis begins in childhood, there are no recent Canadian data on cardiovascular risk factors in provincially or nationally representative samples of youth. OBJECTIVE: To describe the design and methods of the 1999 Quebec Child and Adolescent Health and Social Survey, which assessed the prevalence and distribution of risk factors in a representative sample of Quebec youth. METHODS: School-based, multistage, cluster sampling survey of youth aged nine, 13 and 16 years. Measures included height, weight, subscapular and tricipital skinfolds, blood pressure (measured with the Dinamap), a fasting blood draw for assessment of lipoproteins and glucose, an age-adapted youth questionnaire on lifestyles and a parent questionnaire. RESULTS: One thousand two hundred sixty-seven, 1186 and 1160 subjects aged nine, 13 and 16 years, respectively, responded to the questionnaire and had height, weight, skinfold thickness and blood pressure measured (response proportions of 83%, 79% and 78% respectively); 783, 818 and 874 subjects of the same age agreed to the blood draw (response proportions of 52%, 55% and 59%, respectively). Comparisons of characteristics of participants and nonparticipants in the blood draw showed few differences. The mean relative difference between lipoprotein and glucose values obtained at the study laboratory and a reference method varied from -0.3% to 6.1%. Design effects for means and proportions varied from 1.0 to 1.8. CONCLUSION: Despite its complexity, this survey was able to achieve a high level of precision for multiple measures. It will provide the most complete data on cardiovascular risk factors ever collected among children and adolescents in Canada.