The Contribution of Gestational Diabetes to Diabetes Risk Among First Nations and Non-First Nations Women in Saskatchewan: Results From the DIP: ORRIIGENSS Project.

Objectives: Our aim in this study was to determine the risk for diabetes mellitus (DM) among Saskatchewan First Nations (FN) and non-FN women with prior gestational DM (GDM).

Methods: Using Ministry of Health administrative databases, we conducted a retrospective cohort study of DM risk by GDM occurrence among FN and non-FN women giving birth from 1980 to 2009 and followed to March 31, 2013. We determined frequencies and odds ratios (ORs) of DM in women with/without prior GDM after stratifying by FN status, while adjusting for other DM determinants. Survival curves of women until DM diagnosis were obtained by prior GDM occurrence and stratified by ethnicity and total parity.

Results: De-identified data were obtained for 202,588 women. Of those who developed DM, 2,074 of 10,114 (20.5%) had previously experienced GDM (811 of 3,128 [25.9%]) FN and 1,263 of 6,986 [18.1%] non-FN). Cumulative survival of women with prior GDM until DM was higher for FN than for non-FN women (82% vs 46%), but prior GDM was a stronger predictor of DM within the non-FN cohort (prior GDM vs no GDM: OR, 9.64 for non-FN; OR, 7.05 for FN). Finally, higher total parity interacted with prior GDM to increase DM risk in both groups. With prior GDM and parity ≥3, 93% of FN and 57% of non-FN women subsequently developed DM.

Conclusions: GDM is a leading determinant of T2DM among FN and non-FN women, amplified by higher parity. This contributes to earlier onset diabetes, affecting subsequent pregnancies and increasing risk for chronic diabetic complications. It may also factor into higher type 2 DM rates observed in FN women compared with men.