In Utero Exposure to Preexisting or Gestational Diabetes Mellitus Increases Incidence of Diabetes in the Children of First Nations and Non–First Nations Mothers: A Retrospective Cohort Study

OBJECTIVE We conducted this First Nations–engaged and –co-led project to determine the incidence of diabetes in the children of mothers with preexisting diabetes, gestational diabetes mellitus, and no diabetes and to evaluate whether periconception glycemic control was associated with the risk of diabetes in the children. RESEARCH DESIGN AND METHODS We conducted a longitudinal population-based study using health care administrative data that included all children of mothers aged 12–49 years born between April 1994 and March 2016. The exposure of interest was maternal diabetes status, and we examined both First Nations and non–First Nations mothers. Children were followed for incident diabetes. Among women with preexisting diabetes, periconception HbA1c was evaluated as a predictor. RESULTS There were 2,851,583 children followed to a median age of 16 years (interquartile range 11–22). Among children of non–First Nations mothers, the adjusted hazard ratios for incident diabetes were 5.18 (95% CI 4.82–5.57) with maternal preexisting diabetes and 1.75 (1.65–1.84) with gestational diabetes mellitus. Among children of First Nations mothers, hazard ratios were 7.68 (5.91–9.98) and 2.59 (2.07–3.24), respectively. The hazard ratio for incident diabetes in children of mothers with preexisting diabetes was 0.89 (0.80–0.995, P = 0.04) for each 1% (11 mmol/mol) decrease in periconception HbA1c. CONCLUSIONS Exposure to either preexisting diabetes or gestational diabetes mellitus in utero was associated with an increased incidence of diabetes in children and young adults, with a stronger association among First Nations people. Better periconception glycemic control was associated with decreased diabetes incidence in children of mothers with preexisting diabetes.