Epidemics of type 1 diabetes in China.

OBJECTIVE: The aim of this study was to search for the seasonal and geographic variations in epidemics of type 1 diabetes in China. Research design and methods: Incidence data from 22 type 1 diabetes registration centers across China were analyzed. A Poisson regression model with a sine wave function was applied to evaluate the seasonal trends. A scan statistic was used to examine the occurrence of an epidemic. RESULTS: There was a significant cyclic trend of incidence of type 1 diabetes in China. The northern area had a higher incidence rate than the southern area. Epidemics were discovered in Dalian and Shenyang from late 1992 to late 1993. CONCLUSIONS: There was a strong association of climate and incidence of type 1 diabetes in China, whereby the incidence was higher in the colder areas and in the winter months. Evidence of epidemics existed in two centers in 1992--1993. It is critical to identify the epidemics early and determine the causes of epidemics. [ABSTRACT FROM AUTHOR]