Polymorphisms in inflammation genes, tobacco smoke and furred pets and wheeze in children

Persistent wheeze in childhood is associated with airway inflammation. The present study investigated relationships between polymorphisms in inflammatory genes, exposure to tobacco smoke and furred pets and risk of recurrent wheeze in children. Within a birth cohort of 101,042 children we identified 1111 eighteen month old cases with recurrent wheeze and 735 wheeze-free controls among 11942 children recruited in the Copenhagen area. Polymorphisms in IL-4R, IL-8, IL-13, SPINK5, and CD14 were genotyped. Interviews at gestational wks 12 and 30, and at age 6 and 18 months included questions on number of episodes with wheeze (18 months), exposure to tobacco smoke and pet-keeping. Recurrent wheeze was defined as at least four episodes of wheeze before the child was 18 months old. There was a statistically significant association between the IL-13 Arg144Gln polymorphism and risk of recurrent wheeze (p = 0.01). Furthermore, there was a statistically significant interaction between this polymorphism and exposure to tobacco smoke during pregnancy, though this was probably a chance finding. There were no other statistically significant effects of the polymorphisms or interactions with exposure to tobacco smoke in relation to the risk of recurrent wheeze. Polymorphisms in IL-8 affected the association between pet-keeping and risk of wheeze. Polymorphisms in inflammation genes might affect the association between environmental exposures and risk of recurrent wheeze in early childhood.