Higher maternal age at delivery, and lower birth orders are associated with increased risk of childhood type 1 diabetes mellitus.

In several populations, maternal age at delivery and birth order have been demonstrated to variously affect the risk of Type 1 diabetes mellitus in the offspring. The aim of the present study was to investigate this relation in the Czech population. Questionnaire data on 640 children with childhood-onset Type 1 DM and data on 50 random controls to each case, obtained from the national Birth Registry and matched for the calendar year of birth, were analysed using multivariate logistic regression. The risk of Type 1 DM increases with higher maternal age at birth of the child (OR = 1.07, CI 95 % 1.05 - 1.09 per one year increment), and decreases with higher birth order (OR = 0.70, CI 95 % 0.62 - 0.79 per increment in birth order). There was no significant difference in these effects across the five-years bands of age at diabetes onset. We detected no independent effect of maternal education, either. Our study provides further evidence that the risk of Type 1 diabetes in the offspring increases with higher maternal age at delivery and lower birth order.