Parental TB associated with offspring asthma and rhinitis

BACKGROUND: Infections in early life are associated with asthma and allergies in one-generation settings; however, the link between parental infection and offspring phenotype is rarely investigated. We aim to study the association of parental TB before conception of the offspring with offspring asthma and rhinitis.METHODS: We included 2,965 offspring born in 1985-2004 and registered in the Norwegian prescription database to 1,790 parents born after 1960 with a history of TB, and included in the Norwegian TB registry. Offspring asthma (n = 582) and rhinitis (n = 929) were defined based on diagnosis, type of medication and prescribed medication ≥1 year. Associations of parental TB <8 years, ≥8 years but before offspring´s birth year and after birth (reference category) with offspring asthma and rhinitis were analysed using logistic regression.RESULTS: Asthma risk was higher in persons with parental TB in childhood (OR 1.73, 95% CI 1.20-2.50) or later preconception (OR 1.38, 95% CI 1.00-1.91) than in persons with parental TB after offspring´s birth; this was significant only in the maternal line (childhood: OR 1.95, 95% CI 1.13-3.37; later preconception: OR 1.74, 95% CI 1.08-2.80). Associations with rhinitis were not identified.CONCLUSIONS: Parental childhood TB was associated with higher asthma risk in future offspring. We speculate that TB impacts maternal immunity and dysregulates the offspring´s type 2 immunity, and that TB-induced epigenetic reprograming of immune defences are transferred to the offspring.