Weight change in association with the incidence of type 2 diabetes in adults from Qingdao, China

Abstract

Since the incidence rates and risk factor for type 2 diabetes in Chinese populations had not been well known, the aim of this study was to evaluate the impact of weight change and other risk factors on incident type 2 diabetes in Qingdao, China. A prospective population-based cohort study was carried out, based on subjects aged 35-74 years who participated in the 'Qingdao Diabetes Survey' in 2006. Subjects were free of diabetes at baseline. A total of 1 294 subjects attended the follow up survey between 2009 and 2011. The diagnostic criteria for Diabetes was classified according to both the World Health Organization and the International Diabetes Federation 2006. A logistic regression was built using the backward stepwise selection to assess the effects of risk factors on the incident type 2 diabetes. During a 4-year follow up period, 120 cases with incident type 2 diabetes were identified, with cumulative incidence of diabetes as 11.8% . Participants who developed type 2 diabetes were significantly older, having significantly higher age-adjusted BMI/waist circumference/systolic blood pressure and total cholesterol, than those subjects who remained non-diabetic both in urban and rural areas. Among individuals with no diabetes at the baseline, factors as age, living in the rural areas, baseline BMI and weight change had all independently contributed to the development of diabetes. The multivariate adjusted relative risks (95%CIs) related to the incidence of diabetes were 1.45 (1.13-1.87), 1.93 (1.12-3.34), 1.46 (1.05-2.03) and 1.49 (1.18-1.88), respectively, for a one standard deviation increase in continuous variables. Compared with the reference group of non-obese and with stable weight, factor as weight loss >5% and BMI <28 kg/m² were independently associated with a 67% (RR = 0.33, 95% CI: 0.11-0.97)reduction in the risk of type 2 diabetes, while BMI >28 kg/m² could increase the risk across the levels of weight change. Similar trends were observed in higher waist and weight gain at baseline. This study confirmed the critical importance of obesity in the development of type 2 diabetes. Baseline BMI and weight gain appeared independent predictors on type 2 diabetes.