Candidate genes did not have an impact on the risk of wheezing in children born preterm.

Aim: Our aim was to investigate whether risk factors, including selected genetic variants, appeared with the same frequency in preterm-born and term-born children with respiratory symptoms.

Methods: We conducted an observational study on a cohort at Copenhagen University Hospital Hillerød, Denmark, consisting of 63 preterm-born and 86 term-born children who were included at birth and followed to 6 years of age. Odd ratios (OR) and 95% CIs were calculated.

Results: Valid genotyping data were obtained from 135 children and 126 and 64 parents completed questionnaires at the 1-year and 6-year follows-ups, respectively. The C allele of rs3751972 was associated with an increased wheezing risk at 6 years of age in term-born children, but not in preterm-born children (OR 8.84, 95% CI 1.02-76.72, p = 0.05 versus OR 2.33, 95% CI 0.59-9.20, p = 0.23, respectively). At 1 year of age, preterm-born children with respiratory symptoms were three times as likely to have parents who smoked than those without such symptoms (65% and 21%, respectively, p = 0.005).

Conclusion: Genetic variants known to affect the risk of respiratory symptoms did not seem to affect the risk of wheezing in preterm children. Parental smoking was a significant risk factor for respiratory symptoms.