Rapid increase in the incidence of clinically diagnosed type 2 diabetes in Chinese in Harbin between 1999 and 2005.

Aim: To examine the recent trend in the incidence of clinically diagnosed type 2 diabetes during the period of 1999-2005 in Harbin, China.

Methods: The records of newly diagnosed type 2 diabetes from hospitals and clinics in Harbin were reported to the Harbin Centre for Disease Control and Prevention. About 3 million (33%) of the total population were from six metropolitan districts and over 6 million (67%) from the surrounding counties. Incidence rates and incidence rate ratios (IRR) were estimated using Poisson regression.

Results: During the observational period, 26,953 new cases of diagnosed type 2 diabetes were reported. Among them, 16,367 were from the metropolitan region and 10,586 from the surrounding counties. The incidence rate of type 2 diabetes in the metropolitan region was 3.19 (95% CI: 3.11, 3.27) times as high as that in the surrounding counties. Females had higher incidence rates in younger age groups (<54 years) and lower rates in older age groups (55+ years) than their male counterparts. The incidence increased over time during the period of 1999-2005 by an average of 12% per year (IRR=1.12, 95% CI: 1.11, 1.13). Similar increasing rates were observed in both the county and metropolitan regions.

Conclusions: The incidence of diagnosed type 2 diabetes has increased dramatically in recent years. Although an increasing trend in the incidence of type 2 diabetes exists in both metropolitan and county regions, the county region currently has a substantially lower incidence rate than the metropolitan region.