Trends in prevalence of gestational diabetes mellitus in Zhejiang Province, China, 2016-2018

Limited population-based studies have investigated the secular trend of prevalence of gestational diabetes mellitus (GDM) in mainland China. Therefore, this study aimed to estimate the prevalence of GDM and time trends in Chinese female population. Based on Diabetes Surveillance System of Zhejiang Province, 97,063 diagnosed GDM cases aged 20-50 years were identified from January 1, 2016 to December 31, 2018. Annual prevalence, prevalence rate ratios (PRRs) and average annual percentage change with their 95% confidence intervals (CIs) were reported. The age-standardized overall prevalence of GDM was reported to be 7.30% (95% CI 7.27-7.33%); 9.13% (95% CI 9.07-9.19%) in urban areas and 6.24% (95% CI 6.21-6.27%) in rural areas. Compared with 20-24 years age group, women in advanced age groups (25-50 years) were at higher risk for GDM (PRRs ranged from 1.37 to 8.95 and the 95% CIs did not include the null). Compared with rural areas, the risk for GDM was higher in urban areas (PRR: 1.69, 95% CI 1.67-1.72). The standardized annual prevalence increased from 6.02% in 2016 to 7.94% in 2018, with an average annual increase of 5.48%, and grew more rapidly in rural than urban areas (11.28% vs. 0.00%). This study suggested a significant increase in the prevalence of GDM among Chinese female population in Zhejiang province during 2016-2018, especially in women characterized by advanced age and rural areas.