RESUMO
Objective@#To explore sex differences between weight and systolic blood pressure (SBP) changes among school-age children and adolescents in Beijing, and to provide a basis for priority intervention to control the rapid growth of body weight and blood pressure.@*Methods@#Anthropometric measurement data of 70 288 children and adolescents from primary and high schools in Shunyi District were collected from 2009 to 2018, and a longitudinal dataset with complete data related to weight and BP after individual data linkage was compiled. The age-specific weight and SBP growth rates were calculated, and a linear mixed-effects model was used to identify sex differences in chronological growth rates.@*Results@#Weight and SBP increased with age in both boys and girls, and the mean weight and SBP were higher in boys than in girls across all age groups. The result of the linear mixed-effects model indicated apparent sex differences in weight and SBP growth rates, with an age and sex interaction term(β=-0.35, -0.40, P<0.01). The age at peak weight velocity (PWA) was 12 years old and the age at peak SBP velocity was 13 years old in boys, which occurred one and three years later than for girls, respectively. In addition, the peak weight and SBP velocity were higher in boys than in girls. The curves of the SBP growth rate adjusted for the PWA, showed that the peak SBP velocity occurred two years before PWA and the second peak SBP velocity occurred at the PWA, which indicated "double peaks" in both boys and girls. The SBP growth rate was always higher in boys than in girls, and the rates declined after PWA.@*Conclusion@#Sex differences in weight and SBP growth rates were persistent and obvious in school-age children and adolescents in Beijing and the change in SBP was highly time synchronized with the increase in weight.