Parental autoimmunity and offspring risks of rheumatic diseases: a nationwide population-based study

Objective Familial aggregation of systemic autoimmune diseases is frequently reported, but little is known about how fathers and mothers differentially contribute to the development of autoimmune diseases in their offspring. This study aimed to investigate the impact of maternal and paternal autoimmunity on the risk of offspring rheumatic diseases.Methods We constructed a nationwide population-based cohort using data from the Maternal and Child Health Database and the Taiwan National Health Insurance Research Data (NHIRD) from 2004 to 2019. The outcome was presence of an autoimmune disease in the offspring. Inverse probability of treatment-weighted Cox models were used to estimate adjusted hazard ratios (aHRs) and 95% CIs for autoimmune diseases.Results Babies born to a father or mother with an autoimmune disease had, respectively, 1.22 times and 1.38 times the risk of developing an autoimmune disease compared with their counterparts with no parental autoimmune diseases. Maternal autoimmunity substantially contributed to the risk of SLE (aHR = 5.46, 95% CI: 5.28-5.66), and paternal autoimmunity contributed to the risk of JIA (aHR = 1.76, 95% CI: 1.71-1.81) and of type 1 diabetes mellitus (aHR = 1.59, 95% CI: 1.39-1.81) in their offspring. The contributions of mothers to the risk of development of SLE (aHR = 8.55, 95% CI: 8.10-9.02) and inflammatory myopathy (aHR = 2.08, 95% CI: 1.72-2.51) in their offspring were exacerbated in boys. Babies of two parents with an autoimmune disease showed a 1.39-fold risk of developing an autoimmune disease. The maternal contribution effect was stronger for preterm births than for full-term births.Conclusion This study demonstrated broadly how autoimmune diseases pass from parents to infants of both genders and separately quantified the maternal and paternal contributions to disease.