Joint associations of physical activity and hypertension with the development of type 2 diabetes among urban men and women in Mainland China

Background: Physical activity (PA) and hypertension (HTN) are important influences on the development of type 2 diabetes (T2D). However, the joint impact of PA and HTN on T2D development is unknown. Methods: Two community-based prospective cohort studies, with the same protocols, instruments and questionnaires, were conducted among adults in urban areas of Nanjing, China, during 2004–2007 and 2007–2010. T2D was defined using World Health Organization criteria based on physicians' diagnosis and fasting blood glucose concentration. PA level (sufficient/insufficient) and blood pressure status (hypertensive/normotensive) were assessed at baseline and the third year of follow-up. We pooled and analyzed data from these two studies. Results: Among 4550 participants aged 35 years or older, the three-year cumulative incidence of T2D was 5.1%. After adjusting for potential confounders, participants with sufficient PA were less likely to develop T2D than those with insufficient PA (OR=0.43, 95%CI=0.27, 0.68) and those who were normotensive were less likely to develop T2D than those who were hypertensive (OR=0.39, 95%CI=0.29, 0.51). Compared to participants with insufficient PA and who were hypertensive, those with sufficient PA and hypertension were at lower risk of developing T2D (OR=0.36, 95%CI=0.19, 0.69), as were those with insufficient PA who were normotensive (OR=0.37, 95%CI=0.28, 0.50) and those with sufficient PA who were normotensive (OR=0.19, 95%CI=0.10, 0.37). Conclusions Insufficient PA was found to be associated with the development of T2D among adults with and without hypertension. These findings support a role for promoting higher physical activity levels to lower T2D risk in both hypertensive and non-hypertensive individuals.