Prevalence of gestational diabetes among Chinese and South Asians: A Canadian population-based analysis.

Background: There is considerable geographic variation in gestational diabetes mellitus (GDM) rates. We used data from two Canadian provinces, British Columbia (BC) and Alberta (AB), to determine the impact of ethnicity on GDM prevalence and neonatal outcomes.

Research Design And Methods: All deliveries between 04/01/2004 and 03/31/2010 in AB (n=249,796) and BC (n=248,217) were analyzed. We calculated GDM prevalence among Chinese, South-Asian, and the general population (predominantly Caucasian) women.

Results: Overall GDM prevalence was 4.8% (n=12,036) in AB and 7.2% (n=17,912) in BC. In both provinces, the prevalence of GDM was significantly higher in Chinese (AB:11%; BC:13.5%) and South Asian women (AB:8.4%;BC:13.9%) compared to the general population (AB:4.2%; BC: 5.8%). Chinese women were significantly older (AB:32.7; BC:33.0years) compared to the general population (AB:29.1; BC:30.1years). The odds of GDM relative to the general-population were 2-fold higher for South Asians in both provinces and almost 3-fold higher for Chinese in BC. Among GDM cases, compared to the general population, Chinese and South Asian infants were less likely to be LGA, more likely to be SGA, and had similar neonatal mortality rates.

Conclusions: Compared to the general population, GDM prevalence is higher in Chinese and South Asian Canadians. Increased maternal age is a major contributor to higher prevalence of GDM in Chinese women. GDM rates were higher in both ethnic and general population women in BC compared to AB, suggesting that in addition to differences in ethnic distribution, differences in diagnostic practices are likely contributing to observed geographic differences in GDM prevalence.