Comprehensive physical fitness and high blood pressure in children and adolescents: A national cross-sectional survey in China

Objectives: To assess the association between comprehensive physical fitness and high blood pressure (HBP) among Chinese children and adolescents. Design: National cross-sectional surveys. Methods: 214,301 school students' data aged 7-18 years was extracted in 2014. Six components of physical fitness (forced vital capacity, standing long jump, sit-and-reach, body muscle strength, 50 m dash and endurance running) were measured, standardized and aggregated as a summary physical fitness indicator (PFI). HBP, systolic HBP (SHBP) and diastolic HBP (DHBP) were defined according to sex-, age-and height-specific references in China. Results: The prevalence of HBP, SHBP and DHBP was 8.6%, 4.7% and 5.7%, respectively, and PFI was -0.9 in Chinese children and adolescents. A significant negative association between the PFI and HBP was observed with adjusted prevalence of HBP (10.8% (95% CI: 10.4-11.2) to 7.6% (95% CI: 7.3-8.0), P-trend < 0.001), SHBP (5.7% (95% CI: 5.4-6.1) to 4.4% (95% CI: 4.1-4.6), P-trend < 0.001), and DHBP (7.6% (95% CI: 7.2-7.9) to 4.6% (95% CI: 4.3-4.9), P-trend < 0.001) and their ORs (HBP: 0.87(95% CI: 0.82-0.93) to 0.68(95% CI: 0.64-0.73), P-trend < 0.001; SHBP: 0.86(95% CI: 0.79-0.94) to 0.75(95% CI:0.69-0.82), P-trend < 0.001; DHBP: 0.85(95% CI: 0.79-0.92) to 0.59(95% CI: 0.54-0.64), P-trend < 0.001) declined with the increase in PFI. Stratified nutritional status exhibited a similar negative association between PFI and HBP, SHBP and DHBP in children with normal weight, overnutrition, and undernutrition. Stand long jump, body muscle strength, 50 m dash, and endurance running, had a negative association with HBP, SHBP and DHBP, but forced vital capacity had a positive such association. Sit-and-reach and HBP are not significantly associated. Conclusions: Physical fitness was negatively correlated to the increased HBP in children and adolescents. Comprehensive policies and measures to enhance children and adolescents' physical fitness are urgently needed through the promotion of physical activity, healthy dietary patterns, and strategies of educational guidelines to reduce schoolwork, which will in turn reduce the cardiovascular burdens in the future. (C) 2020 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.