The mediation and interaction of the obesity index between moderate-vigorous recreational physical activity and hypertension

Previous studies showed that physical activity (PA) is concerned with hypertension (HTN). However, the mediation and interaction role of the obesity index: body mass index (BMI), waist-hip ratio (WHR), body fat rate (BFR) and visceral fat index (VFI) between PA and HTN has never been studied. Therefore, the purpose of this study was to assess the mediation and interaction of the obesity index between moderate-vigorous recreational physical activity (MVRPA) and HTN. We conducted a cross-sectional study of 4710 individuals aged 41 or older in Torch Development Zone, Zhongshan City. The mediation and interaction of the obesity index were evaluated by a four-way decomposition. 48.07% of participants had HTN among these groups. In the adjusted linear regression model, MVRPA was significantly correlated with WHR (beta +/- SE = -0.005 +/- 0.002; P<0.05). Compared to sufficient MVRPA (odds ratio (OR) = 1.35), 95% (confidence interval (CI) = 1.17-1.56), insufficient MVRPA increased the risk of developing HTN. Furthermore, there were associations between BMI, WHR, BFR, VFI and HTN where the adjusted ORs and 95% CIs were 1.11 (1.09-1.13), 6.23 (2.61-14.90), 1.04 (1.03-1.06), 1.07 (1.06-1.09), respectively. The mediation analyses suggested that the impact of MVRPA on HTN risk may partly be explained by changes in obesity index, with a pure indirect mediation of WHR between MVRPA and HTN (P<0.05). Therefore, weight control, especially reducing abdominal obesity and maintaining adequate MVRPA, may lead to more proper control of HTN.