Polymorphism, Nasopharyngeal Bacterial Colonization, and the Development of Childhood Asthma: A Prospective Birth-Cohort Study in Finnish Children.

We aimed to explore the role of TLR4 (rs4986790) polymorphism in the nasopharyngeal (NP) bacterial colonization and its consequent impact on the development of childhood asthma. A semi-quantitative culture of NP swabs was performed on 473 children at 2 months of age and on 213 children at 13 months of age. polymorphism was analyzed for 396 children. Children were followed from birth to the age of 7.5 years and the final outcome was physician-diagnosed asthma. The associations between genotype, bacterial colonization, and asthma were analyzed. Children with TLR4 AG or GG genotype were more often colonized with at 2 months of age ( = 0.009) and at 13 months of age ( = 0.018). Children who were colonized with at 13 months of age had a significantly higher risk of later development of asthma ( = 0.004). or colonization at 2 months of age or genotype Asp299Gly were not associated with the development of childhood asthma. Asp299Gly polymorphism was associated with an increased risk of colonization of and in children. The colonization with at 13 months of age was associated with a higher risk of later development of childhood asthma.