Leg-to-trunk ratio and the risk of hypertension in children and adolescents: a population-based study

Background Blood pressure (BP) is positively associated with height in childhood; however its relationship with components of height is unclear. This study aimed to evaluate the association between ratio of height components, leg-to-trunk ratio (LTR) and high blood pressure (HBP) in Chinese children and adolescents aged 9-17. Methods Data of 149 073 participants enrolled in Chinese National Survey on Students' Constitution and Health in 2010 were used. HBP was defined according to sex- ,age- and height-specific references. LTR was calculated by dividing leg length by sitting height and categorized as low, medium and high according to sex- and age- specific z-score. Results Larger LTR was associated with declined levels of BP across the height and age spectrum in both sexes. Boys and girls with high LTR were associated with decreases of 5.4 (95% confidence interval: 4.6, 6.2) and 2.7(2.0, 3.4)% in HBP, respectively, compared with their peers of low LTR. A similar pattern was also observed in different age, urban/rural area and body mass index strata. Conclusions Low LTR was associated with elevated risk of HBP in youths. Our findings support using LTR to identify children and adolescents at elevated risk of hypertension in early life.