Interaction of General or Central Obesity and Hypertension on Diabetes: Sex-Specific Differences in a Rural Population in Northeast China

PURPOSE: Some studies have established an association between hypertension or obesity and the risk of diabetes. This study aimed to examine the interaction of hypertension and obesity on diabetes. PARTICIPANTS AND METHODS: The data of 11,731 Chinese men and women were analyzed from the 2012–2013 Northeast China Rural Cardiovascular Health Study. The interaction was examined by both additive and multiplicative scales. General obesity was measured by body mass index (BMI); central obesity was defined by waist circumference (WC), waist-to-height ratio (WHtR) and waist-to-hip ratio (WHpR). RESULTS: After controlling for potential confounders, the odds ratios for diabetes were 3.864 (3.205–4.660), 4.500 (3.673–5.514), 4.932 (3.888–6.255) and 4.701 (3.817–5.788) for the combinations of hypertension and BMI, WC, WHtR or WHpR, respectively, which had the highest risk of diabetes among the four combinations. Notwithstanding the multiplicative interactions showed statistically significant in all analyses, the results of additive interactions were not consistent, suggesting the diabetes risk from female BMI (relative excess risk due to interaction (RERI): 1.136, 95% CI: 0.127–2.146, attributable proportion due to interaction (AP): 0.267, 95% CI: 0.057–0.477, synergy index (S):1.536, 95% CI: 1.017–2.321) or female WHpR (RERI: 1.076, 95% CI: 0.150–2.002, AP:0.205, 95% CI: 0.037–0.374, S:1.340, 95% CI: 1.012–1.775) was additive to the risk from hypertension. CONCLUSION: The findings suggest that high BMI and high WHpR have synergistic interactions with hypertension on the risk of diabetes for females. The results of this study also suggest that BMI and WHpR, rather than WC, should be used for the diagnosis of metabolic syndrome in Chinese population.