Background— Although obesity is associated with important hemodynamic disturbances, there are few data on population-wide blood pressure (BP) distribution in children and adolescents in this era of endemic pediatric obesity. Methods and Results— We conducted a school-based survey of a representative sample of youth aged 9, 13, and 16 years in Quebec, Canada. Resting BP was measured with an oscillometric device in 3589 subjects (80% response). Additional measures included height, weight, and subscapular and triceps skinfold thickness, an age-appropriate questionnaire, and a fasting blood draw. Mean (SD) systolic/diastolic BP (SBP/DBP) levels in 9-, 13-, and 16-year-olds were 103 (9)/57 (6), 113 (12)/58 (7), and 124 (14)/61 (7) mm Hg in males and 103 (10)/57 (6), 111 (11)/60 (7), and 114 (11)/62 (7) mm Hg in females. The prevalence of high-normal or elevated SBP was 12%, 22%, and 30% among 9-, 13-, and 16-year-old males, respectively, and 14%, 19%, and 17% among same-aged females. The prevalence of high-normal or elevated DBP was <1%. In multiple linear regression analysis, body mass index was consistently associated with SBP and DBP in all age-gender groups. Conclusions— Mean SBP and the prevalence of high-normal and elevated SBP are elevated in children and adolescents. Public policy, public health programs, and clinical preventive measures are urgently needed to address the obesity epidemic and its hemodynamic consequences.

Objectives. Report the 8-year impact on body size, physical activity, and diet of a community-based diabetes prevention program for elementary-school children in a Kanien'kehá:ka (Mohawk) community in Canada.Methods. Follow-up (1994–1996) of subjects in the intervention and comparison community and repeat cross-sectional measurements in the intervention community alone from 1994 to 2002. Measures included triceps and subscapular skinfold thicknesses, body mass index (BMI), weekly number of 15-minute episodes of physical activity, run/walk test times, television watching, and consumption of sugared foods, fatty foods, and fruits and vegetables.Results. The longitudinal data of 1994–1996 showed some early positive effects of the program on skinfold thickness but not on BMI, physical activity, fitness, or diet. Repeat cross-sectional measures from 1994 to 2002 showed increases in skinfold thickness and BMI. Physical activity, fitness, and television watching showed favorable trends from 1994 to 1999 that were not sustained in 2002. Key high-fat and high-sugar foods consumption decreased, as did consumption of fruits and vegetables.Conclusions. Although early results showed some successes in reducing risk factors for type 2 diabetes, these benefits were not maintained over 8 years.

Analyzing the relationship between the baseline value and subsequent change of a continuous variable is a frequent matter of inquiry in cohort studies. These analyses are surprisingly complex, particularly if only two waves of data are available. It is unclear for non-biostatisticians where the complexity of this analysis lies and which statistical method is adequate. With the help of simulated longitudinal data of body mass index in children, we review statistical methods for the analysis of the association between the baseline value and subsequent change, assuming linear growth with time. Key issues in such analyses are mathematical coupling, measurement error, variability of change between individuals, and regression to the mean. Ideally, it is better to rely on multiple repeated measurements at different times and a linear random effects model is a standard approach if more than two waves of data are available. If only two waves of data are available, our simulations show that Blomqvist’s method – which consists in adjusting for measurement error variance the estimated regression coefficient of observed change on baseline value – provides accurate estimates. The adequacy of the methods to assess the relationship between the baseline value and subsequent change depends on the number of data waves, the availability of information on measurement error, and the variability of change between individuals.

Background: The Angiotensin-Converting Enzyme-2 (ACE2) gene, located on chromosome X, is believed to be implicated in blood pressure regulation. However the few studies that have examined this association have yielded mixed results. The objective of this study was to assess the association between tag single nucleotide polymorphisms (SNPs) in the angiotensin-converting enzyme-2 gene with blood pressure and blood pressure change in adolescents. Methods: Participants in the Nicotine Dependence in Teens (NDIT) cohort study with blood or saliva samples and at least 3 blood pressure measurements over 5 years were included in the analytic sample (n = 555). Linear growth curve models stratified on sex and ethnicity were used to assess the association between four tag SNPs in the ACE2 gene and systolic (SBP) and diastolic blood pressure (DBP), and blood pressure change. Results: In males of European descent, rs2074192 and rs233575 were significantly associated with SBP and DBP, and rs2158083 was associated with SBP. In French Canadian males, rs233575 and rs2158083 were significantly associated with DBP. Among females of European descent, rs2074192, rs233575, and rs2158083 were significantly associated with change in SBP over 5 years. Conclusions: This is the first study to assess the association between the ACE2 gene with blood pressure and blood pressure change in a cohort of adolescents. Results indicate that several ACE2 gene SNPs are associated with blood pressure or blood pressure change in persons of European descent. However the therapeutic potential of these SNPs should be explored.