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.