Uric acid mediated the relationship between obesity and hypertension in children and adolescents: A population‑based cohort study

Background Obesity and hyperuricemia (HUA) often coexist and have been widely accepted as risk factors for hypertension, but the role of uric acid (UA) in the relationship between obesity and hypertension remains unknown in children and adolescents. Methods A total of 7525 subjects aged 6-16 years were from the School-based Cardiovascular and Bone Health Promotion Program (SCVBH) at baseline (2017) and followed up in 2019. Multivariable logistic regression with interaction terms, cross-lagged panel analysis, and causal mediation model were applied to delineate the joint impact of obesity and HUA on hypertension, including the interaction effect, the temporal association, and the mediating effect of UA in the relationship between obesity and hypertension. Results There were 10.8% of the participants with normotension at baseline developed hypertension after two years of follow-up. Cross-lagged panel analysis showed that the two-time point association was significant only from baseline BMI to follow-up UA (β1=0.302, P<0.001), but not from baseline UA to follow-up BMI (β2= 0.002, P=0.745). Multivariable logistic regression showed that both obesity and HUA increased the risk of hypertension, but no interaction effect between HUA and obesity. The causal mediation analysis found that UA partially mediated the association between BMI and SBP (mediate proportion: 20.3%, 95% CI: 17.4-22.9%) or DBP (mediate proportion: 11.9%, 95% CI: 3.9-18.2%). The results were consistent in the analysis of systolic hypertension rather than diastolic hypertension. Conclusions It is mediating effect that UA played in the progress from obesity to hypertension, particularly systolic hypertension in children and adolescents.