Objective: To investigate whether prenatal exposure to indoor fine particulate matter (PM2.5) affects susceptibility to wheezing in children, and to determine whether genetic factor modify this environmental effect.
Methods: The study population consisted of the 323 children with indoor PM2.5 data in a birth cohort. Recurrent wheezing was determined as 2 or more wheezing episodes diagnosed by physicians in the first 2 years of age. Indoor PM2.5 was measured during pregnancy. Genotyping for TLR4 (rs1927911) was performed by TaqMan.
Results: Prenatal indoor PM2.5 exposure increased the risk of recurrent wheezing in 2 years of age (aOR 3.52; 95% CI 1.50-8.30). TLR4 CC increased the effect of prenatal indoor PM2.5 exposure on recurrent wheezing (aOR 7.00; 95% CI 1.41-34.73; p for interaction 0.153).
Conclusion: Indoor PM2.5 exposure during the prenatal period increased susceptibility to recurrent wheezing. This effect was modified by polymorphisms in TLR4. Reducing PM2.5 exposure from the prenatal period may prevent wheezing in susceptible children.