Epidemiology of Diabetes in Pregnancy Among First Nations and Non-First Nations Women in Saskatchewan, 1980‒2013. Part 1: Populations, Methodology and Frequencies (1980‒2009); Results From the DIP: ORRIIGENSS Project

Objectives: Because of the immediate and long-term consequences of diabetes in pregnancy (DIP) for mother and child, we compared frequencies of gestational diabetes (GDM) and pre-GDM between First Nations (FN) and non-FN people in Saskatchewan from 1980 to 2009.

Methods: Using Ministry of Health administrative databases, we conducted a retrospective cohort study of GDM and pre-GDM rates within all FN and non-FN pregnancies in Saskatchewan. Annual crude and 10-year age-adjusted incidence of GDM and pre-GDM were determined as were maternal age-specific rates of DIP.

Results: De-identified data were obtained for 69,176 FN and 344,410 non-FN pregnancies. The crude annual incidence of GDM rose from 1.0% to 6.6% among FN and from 0.4% to 3.6% among non-FN between 1980 and 2009. The crude annual incidence of pre-GDM rose from 0.7% to 2.0% among FN and from 0.4% to 0.9% among non-FN over the same period. The 10-year age-standardized incidence of GDM increased from 3.53% in 1980-1989 to 8.37% in 2000-2009 for FN, and from 1.55% to 3.13% for non-FN. For pre-GDM, the corresponding increases were from 1.65% to 3.26% for FN and from 0.5% to 0.91% for non-FN. Both GDM and pre-GDM rates increased with increasing maternal age, reaching 10.9% and 8.0% of FN pregnancies, and 7.7% and 1.1% of non-FN pregnancies, respectively, for mothers >40 years old.

Conclusions: The proportion of pregnancies complicated by DIP increased steadily among FN and non-FN women in Saskatchewan in 1980‒2009, but the incidence of GDM and pre-GDM is 2- to 3-fold higher among FN.