OBJECTIVETo explore type 2 diabetes prevalence and its risk factors among migrants and nonmigrants aged 35 years and older in Three Gorge Dam area in Yichang City of Hubei province, China.

METHODSA sample of 9865 rural residents (including 1949 Three Gorge Dam migrants and 7916 nonmigrants) aged 35 years old and over was selected from September to December in 2007 by the method of multi-stage cluster random sampling in Yiling district, Yichang City of Hubei province. The study subjects were assessed by interview, examination, and blood samples. Information on demographics, migrant information, lifestyle, history of diabetes and hypertension was obtained by a questionnaire interview. An overnight fasting blood specimen was collected to measure serum glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C). Height, weight, waist circumference, hip circumference and blood pressure were measured. Oral glucose tolerance test (OGTT) was carried out for those whose fasting glucose was equal to or exceeded 6.1 mmol/L. The standardized prevalence of type 2 diabetes was calculated based on national census in the year of 2000. Multiple logistic regression analysis was used to explore the potential risk factors of type 2 diabetes.

RESULTSThe crude prevalence of type 2 diabetes among nonmigrants was 3.93% (310/7885) (male: 3.90% (129/3304), female: 3.95% (181/4581)), and that of migrants was 6.55% (127/1939) (male: 6.85% (52/759), female: 6.36% (75/1180)). The crude prevalence of type 2 diabetes among migrants was higher than that of nonmigrants (χ² = 25.10, P < 0.01 (male: χ² = 12.59, P < 0.01; female: χ² = 12.78, P < 0.01)). The prevalence of type 2 diabetes among nonmigrants was 3.87% in males and 4.15% in females. The standardized prevalence of type 2 diabetes among migrants was 6.92% in males and 6.33% in females. Logistic regression analysis showed that age (taking 35 - 44 years old as reference, 45 - 54 years old: OR = 1.45, 95%CI: 1.07 - 1.95; 55 - 64 years old: OR = 2.08, 95%CI: 1.53 - 2.84; 65 years old and over: OR = 1.85, 95%CI: 1.25 - 2.75), family history of diabetes (OR = 2.83, 95%CI: 1.70 - 4.72), overweight or obesity (overweight: OR = 1.36, 95%CI: 1.05 - 1.78; obesity: OR = 2.11, 95%CI: 1.47 - 3.01), central obesity (OR = 1.84, 95%CI: 1.39 - 2.44), abnormal triglyceride (OR = 1.54, 95%CI: 1.21 - 1.97), abnormal total cholesterol (OR = 1.40, 95%CI: 1.11 - 1.77) and abnormal LDL-C (OR = 1.82, 95%CI: 1.19 - 2.79) increased the risk of type 2 diabetes, and regular physical activity (OR = 0.57, 95%CI: 0.45 - 0.72) was the protective factor of type 2 diabetes.

CONCLUSIONThe prevalence of type 2 diabetes among Three Gorge Dam migrants was higher than that of nonmigrants. Increasing age, regular physical activity, family history of diabetes, overweight or obesity, central obesity, abnormal triglyceride, abnormal total cholesterol and abnormal LDL-C were related to type 2 diabetes.