Increasing trend in the prevalence of Type 2 diabetes and pre-diabetes in the Chinese rural and urban population in Qingdao, China

Aims To determine the secular trend of prevalence of Type 2 diabetes and pre-diabetes in a Chinese population from 2001 to 2006. Methods Two consecutive population-based surveys for diabetes were conducted in a randomly selected population aged 35-74 years and living in Qingdao, China in 2001-2002 (n = 10854) and 2006 (n = 4416). All participants underwent standardized 2-h 75-g oral glucose tolerance tests (OGTTs), along with fasting capillary plasma glucose (FCG) tests in 2006. One urban community underwent OGTTs directly in 2002 (n = 1815), while a two-step screening strategy using FCG as a first-line screening test followed by OGTTs was used in 9039 individuals in 2001. Diabetes and pre-diabetes was defined according to the 2006 World Health Organization/International Diabetes Federation criteria. Results Based on the results of direct OGTTs, the age-standardized prevalence of diabetes and pre-diabetes in urban areas was 12.2 and 15.4% in 2002, whereas the prevalences were 18.8 and 28.7% in urban areas and 14.1 and 20.2% in rural areas in 2006 (P < 0.001, in urban areas). Using the two-step screening strategy, the prevalence of diabetes in 2001 was 10.1% in urban and 7.7% in rural areas and 13.8% in urban and 12.2% in rural areas in 2006 (P < 0.001). Based on the data of the 2006 survey, the two-step screening strategy missed 30.2% of diabetes cases when compared with the number defined by the direct OGTT approach. Conclusions Qingdao has experienced a marked increase in the prevalence of diabetes and pre-diabetes in the past 5 years. Intervention to prevent a further increase in the prevalence of diabetes is urgently required.