Maternal Gestational Diabetes and Type 2 Diabetes During Pregnancy and Risk of Childhood Asthma in Offspring

Objective: To examine maternal preexisting type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) on risk of childhood asthma.

Study design: This retrospective birth cohort study included 97 554 singletons born in 2007-2011 within hospitals from a single integrated healthcare system. Children were prospectively followed from age 5 until December 31, 2017, using electronic medical records. Relative risks of childhood asthma associated with maternal diabetes in utero were estimated by hazard ratios using Cox regression adjusting for potential confounders.

Results: There were 3119 children (3.2%) who were exposed to preexisting T2D and 9836 (10.1%) to GDM. Among mothers with GDM, 3380 (34.4%) were dispensed antidiabetic medication during pregnancy. During a median of 7.6 years (IQR, 6.3-9.0 years) after birth, 15 125 children (15.5%) were diagnosed with asthma after age 5. Maternal diabetes interacted with maternal asthma history to affect child's asthma risk (P = .05). Among children without maternal asthma (n = 89 487), the adjusted hazard ratios for childhood asthma were 1.21 (95% CI, 1.08-1.36; P < .001) for exposure to T2D, 1.12 (95% CI, 1.01-1.25; P = .04) for GDM requiring antidiabetic medications, and 1.01 (95% CI, 0.93-1.10; P = .82) for GDM not requiring medications compared with no diabetes during pregnancy. The corresponding hazard ratios were 1.53 (95% CI, 1.19-1.96; P < .001), 1.11 (95% CI, 0.65-1.46; P = .44), and 0.84 (95% CI, 0.66-1.08; P = .17) among children without maternal asthma (n = 8067). Gestational age at GDM diagnosis was not associated with childhood asthma (P = .27).

Conclusions: The risk of childhood asthma was predominately observed for exposure to preexisting T2D, small for GDM requiring medication, and not increased for GDM not requiring medication during pregnancy, compared with no diabetes during pregnancy.