Epidemiological characteristics of diabetes mellitus and impaired glucose regulation in a Chinese adult population: the Shanghai Diabetes Studies, a cross-sectional 3-year follow-up study in Shanghai urban communities

Aims/hypothesis To estimate the prevalence and incidence of diabetes mellitus and impaired glucose regulation (IGR) in a Chinese population aged 20-94 years. Subjects and methods A group of 5,628 randomly selected adults, aged 20-94 years, living in the Huayang and Caoyang communities in Shanghai, China, were investigated between 1998 and 2001. During 2002-04, 2,666 subjects were followed up. All the participants underwent anthropometric measurements, blood biochemical analyses and a 75-g OGTT. Results Based on the 2000 census data of China, the age-standardised prevalences were 6.87% for diabetes and 8.53% for IGR at baseline. More than two in five cases with diabetes were undiagnosed. The age-adjusted prevalence of diabetes and IGR increased with age. The age-adjusted prevalences of hypertension, dyslipidaemia and overweight in males were significantly higher (p < 0.001) than in females. The 3-year cumulative incidence rates of diabetes and IGR were 4.96 and 11.10%, respectively. The relative risk of developing diabetes was significantly higher in subjects with IGR than in subjects with NGT (p < 0.001). Conclusions/interpretation The prevalence and incidence rates for diabetes or IGR have increased dramatically over the last decades, especially in younger age groups. A large proportion of cases are undiagnosed. We strongly recommend that population-based diabetes screening programmes should be implemented and generalised for younger people.