MATERNAL autoimmune disease during pregnancy was associated with a 57% higher risk of Type 1 diabetes (T1D) in offspring, according to a Swedish nationwide cohort study. However, similar associations with paternal autoimmune disease suggest shared familial susceptibility may contribute to the increased risk, alongside potential effects specific to pregnancy.
The population-based study included 1,455,645 children born in Sweden between 2001 and 2014. Researchers investigated whether maternal autoimmune diseases diagnosed before or during pregnancy were associated with offspring T1D, comparing findings with paternal autoimmune disease and examining familial factors.
During a median follow-up of 15.3 years, 10,273 children (0.71%) developed T1D. Maternal autoimmune disease during pregnancy was associated with an increased risk of offspring T1D (adjusted hazard ratio [HR]: 1.57; 95% confidence interval [CI]: 1.46–1.68).
Paternal autoimmune disease diagnosed before childbirth showed a similar association (adjusted HR: 1.51; 95% CI: 1.37–1.67). Direct comparison found no overall difference between maternal and paternal associations (ratio of HR: 1.04; 95% CI: 0.92–1.17), although differences emerged across specific autoimmune disease categories.
The researchers also identified a gradient in offspring T1D risk according to parental T1D status. Risk was highest when both parents had T1D, followed by offspring with an affected father only and then those with an affected mother only.
Cousin analyses provided further insight into the contribution of shared familial factors. The association between maternal autoimmune disease and offspring T1D was attenuated but remained evident among cousins (HR: 1.27; 95% CI: 1.08–1.50).
The findings suggest that shared familial susceptibility may contribute to the association between parental autoimmune disease and offspring T1D. The similar overall associations observed for maternal and paternal autoimmune disease support a contribution from factors beyond the intrauterine environment.
However, differences across specific autoimmune disease categories indicate that some conditions may involve parent-specific influences. The researchers concluded that both shared familial susceptibility and potential intrauterine mechanisms could contribute to the intergenerational transmission of T1D risk.
Further investigation of these pathways may help clarify how parental autoimmune conditions influence the development of T1D in offspring.
Reference
Zhang H et al. Maternal autoimmune diseases during pregnancy and offspring Type 1 diabetes. JAMA Pediatr. 2026;DOI:10.1001/jamapediatrics.2026.4894.
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