Geographic, gender and seasonal variation of diabetes: a nationwide study among 1.4 million participants.

BACKGROUND: China experienced a rapid increase in the prevalence of diabetes.

OBJECTIVES: To assess the prevalence of diabetes among Chinese adults who attend preventive physical examination, and analyzed geographical and gender difference in seasonal variation of fasting blood glucose (FBG).

METHODS: The study used data from 1,390,088 participants attending preventive health examination at 430 health screening centers in 220 cities. Diagnosis of diabetes and prediabetes were based on FBG and hemoglobinA1c and self-report physician's diagnosis. We calculated age and sex standardized prevalence of diabetes according to the sixth Chinese population census data in 2010. Geographical distribution of diabetes and prediabetes were displayed on the country map. FBG were analyzed to detect the seasonal variation adjusted for age and gender by geographic location.

RESULTS: The standardized prevalence of diabetes was 8.70% (95% CI, 8.22%-9.19%), 10.7% in men and 6.61% in women. Among those with diabetes, 43.7% (95% CI, 40.9%-46.5%) were aware of their conditions and 38.5% (95% CI, 36.0%-41.1%) were treated. Only 49.3% (95% CI, 47.0%-51.6%) of treated patients achieved glycemic control. The mean level of FBG was higher in winter than summer and in the northern than the southern.

CONCLUSIONS: The prevalence of diabetes was high whilst the percentages of awareness, treatment and glycemic control were low among adults. Effective measures are needed to prevent and manage diabetes in China. Geographic and seasonal variation of diabetes should be considered for its prevention and control.