Role of waist measures in characterizing the lipid and blood pressure assessment of adolescents classified by body mass index

Objective: To determine if the interaction of waist circumference percentile and waist to height ratio (WHtR) with body mass index (BMI) may serve to provide further risk specification in the lipid and blood pressure assessment of adolescents beyond BMI classification. Design: Population-based, cross-sectional study. Data collected during the 2009-2010 academic school year. Setting: Geographically and administratively defined Niagara Region, Ontario, Canada. Data collected in school, during subjects' mandatory physical education class. Part of the Heart Niagara Inc Healthy Heart Schools' Program. Participants: Entire population of grade 9 (14- and 15-year-old) students in the Niagara Region, Ontario. Four thousand eight hundred eighty-four students enrolled in grade 9 during the study period, of which 4104 participated (51% male) and 3248 (79%) had complete data. Main Outcome Measures: Nonfasting lipid values and blood pressure categories in subjects categorized based on BMI/waist circumference percentile and BMI/WHtR. Results: The associations between blood pressure, lipid profile, and measures of adiposity (BMI alone, BMI/waist circumference percentile, and BMI/WHtR) were statistically significant but had a limited strength and were not statistically significant from each other. For overweight and obese subjects, increased WHtR categories were associated with worsened lipid profile and increased odds of hypertension both relative to subjects with both normal BMI and normal WHtR and subjects with normal WHtR within each BMI category. Conclusion: Waist measures should be included in the screening and assessment of overweight and obese adolescents.