title: Emergence of sex differences in prevalence of high systolic blood pressure: analysis of a longitudinal adolescent cohort.
abstract: 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.
  
  
  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.
authors.affiliation: Departments of Medicine, McGill University, Montreal, Quebec, Canada. Kaberi.Dasgupta@mcgill.ca
authors.forename: Kaberi
authors.initials: K
authors.lastname: Dasgupta
authors.forename: Jennifer
authors.initials: J
authors.lastname: O'Loughlin
authors.forename: Shunfu
authors.initials: S
authors.lastname: Chen
authors.forename: Igor
authors.initials: I
authors.lastname: Karp
authors.forename: Gilles
authors.initials: G
authors.lastname: Paradis
authors.forename: Johanne
authors.initials: J
authors.lastname: Tremblay
authors.forename: Pavel
authors.initials: P
authors.lastname: Hamet
authors.forename: Louise
authors.initials: L
authors.lastname: Pilote
mesh_terms: D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D012727:Sex Characteristics; D013599:Systole