Objective: To examine the effects of the size of the mother and the newborn, including placental weight and gestational age at delivery, on the risk for young adult-onset type 1 diabetes (T1DM) and type 2 diabetes (T2DM).
Design: Case-control study.
Setting: Finland.
Population: Subjects with T1DM and T2DM aged 15-39 at diagnosis between the years 1992 and 1996. The number of case-control pairs was 858 for T1DM and 355 for T2DM.
Methods: Diabetic subjects were identified from the Finnish national healthcare registers and reports from diabetes nurses. Control subjects were obtained from the population register. Data on perinatal factors were obtained from the original healthcare records. The odds ratios (ORs) for both types of diabetes were estimated using conditional logistic regression.
Results: The risk for early-onset T2DM decreased with increasing birthweight until 4.2 kg (OR 0.49 (95% confidence interval 0.37-0.66) per 1 kg), but with birthweight above 4.2 kg the risk increased (OR 4.8 (1.3-17.6) per 1 kg). The risk for T2DM decreased also with increasing birth length (OR 0.88 (0.81-0.95) per 1 cm), body mass index at birth (OR 0.81 (0.73-0.90) per 1 kg/m2), and placental weight (OR 0.77 (0.61-0.98) per 100 g). The latter was not significant when adjusted for birthweight. The examined perinatal factors did not affect the risk for T1DM in young adults.
Conclusions: Birth size significantly affects the risk for T2DM diagnosed in young adulthood but no evidence was found of an association between late-onset T1DM and perinatal factors.