Epidemiological evidence that maternal diabetes does not appear to increase the risk for Down syndrome

In 1997, Narchi and Kulaylat, studying the incidence of Down syndrome in infants of gestational diabetic mothers, concluded that maternal diabetes increases the risk for Down syndrome, but failed to control the maternal age in their analysis. Using data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), we analyzed the relationship between Down syndrome and maternal diabetes mellitus, and maternal gestational diabetes, controlling the maternal age through the pair-matching analysis, stratifying by maternal age and logistic regression analysis. The analyses show that maternal age is related either to Down syndrome as well as to both types of maternal diabetes. Thus, the overall analysis could be confounded by maternal age. Once we controlled the maternal age, the risk of maternal diabetes mellitus for Down syndrome is: odds ratio (OR) = 0.92 (0.41-2.07); P = 0.83. Controlling maternal age in gestational diabetes, the risk is OR = 1.18 (0.61-2.35); P > 0.70. Based on our results, we conclude that Down syndrome is related to maternal age, but does not seem to be related to any type of maternal diabetes.