Emergence of sex differences in prevalence of high systolic blood pressure: analysis of a longitudinal adolescent cohort.

BACKGROUND: High systolic blood pressure (SBP) occurs more frequently both among men and boys than among women and girls. No longitudinal study has investigated whether the impact of SBP determinants differ according to sex in youth. METHODS AND
RESULTS: Between 1999 and 2005, an adolescent cohort (n=1267) completed a questionnaire survey and underwent biannual blood pressure and anthropometric assessment (grades 7, 9, and 11). Boys accounted for approximately 50% of those with high SBP at grade 7 and 9 assessments but 67% of those with high SBP at the grade 11 assessment. As computed through a generalized estimating equations logistic regression model (sex, age, sex and age interaction term, overweight, physical activity, sedentary behavior, heart rate, household income, tobacco use, and 4 language categories), the likelihood of high SBP values among boys compared with girls was 1.29 (95% CI, 0.77 to 2.16) in grade 7, 1.98 (95% CI, 1.35 to 2.93) in grade 9, and 2.74 (95% CI, 1.52 to 4.94) in grade 11. Although there was a significant interaction between sex and age, interaction terms of sex with overweight, sedentary behavior, and physical activity were not statistically significant. Overweight (odds ratio [OR], 2.63; 95% CI, 1.76 to 3.92) and sedentary behavior (OR, 1.17 for increment of 5 hours weekly; 95% CI 1.04 to 1.33) demonstrated positive associations with high SBP values. Physical activity was inversely associated with the presence of high SBP (OR, 0.92 for increment of 5 activities in 7 days; 95% CI, 0.84 to 1.00).
CONCLUSIONS: Boys are more likely than girls to develop high SBP as they approach adulthood. Even among overweight adolescents, reducing sedentary behavior and increasing physical activity may lower the risk of high SBP.