Profiles of pregnancy and early-life urban and lifestyle exposures and respiratory health in children

Introduction: While previous studies identified environmental and lifestyle factors independently associated with respiratory health, this study aims at identifying combined pregnancy and early-life urban and lifestyle exposure profiles associated with respiratory health in children. Material and Methods: This study is based on the HELIX project, combining 6 prospective birth cohorts. Associations between profiles of pregnancy (38 exposures) and early-life exposures (88 exposures) identified by clustering analysis and respiratory health outcomes were estimated by regression models adjusted on confounders. Results: Among the 1,033 included children (mean±SD age: 8.2±1.6 years old, 47% of girls), the mean±SD FEV1 and FVC were 99±13% and 101±14%, respectively, and 12%, 12% and 24% reported ever-asthma, wheezing and rhinitis, respectively. Two early-life exposure profiles were associated with lower levels of FEV1, compared to the profile with globally low exposures. The first profile was characterized by low number of natural spaces and high exposure to built environment and road traffic. The second profile, characterized by high exposure to meteorological factors and low levels of all other exposures, was also associated with a higher risk of ever-asthma and wheezing. Finally, a pregnancy exposure profile (characterized by high levels of exposure to all risk factors, but a healthy maternal lifestyle) was associated with a lower risk of wheezing and rhinitis compared to the pregnancy profile characterized by overall low exposures to all factors. Conclusion: This comprehensive study identified early-life urban and lifestyle exposure profiles associated with respiratory health in children.