Perinatal & Pediatric
Combined effects of indoor environmental and outdoor PM2.5 influences on early asthma in the ECHO birth cohort consortium Akihiro Shiroshita* Akihiro Shiroshita Antonella Zanobetti Brent A. Coull Patrick H. Ryan Soma Datta Jeffrey Blossom Emily Oken James E. Gern Heike Luttmann-Gibson Eneida A. Mendonca Sima K. Ramratnam Sheryl L. Rifas-Shiman Joanne E Sordillo Veronica A. Wang Paloma I. Beamer Daniel J. Jackson Christine C. Johnson Gurjit K. Khurana Hershey Fernando D. Martinez Rachel L. Miller Katherine Rivera-Spoljaric Edward M. Zoratti Tina V. Hartert Diane R. Gold
Background: The individual effects of both indoor and outdoor environmental exposures remain unknown. This study aimed to evaluate the independent associations of water damage/home dampness, pets, dust mite allergen, and PM2.5 with childhood asthma development.
Methods: We included children from nine birth cohort sites from ECHO (Environmental Influences on Child Health Outcomes), including Project Viva and CREW (CAS, CCAAPS, CCCEH, COAST, EHAAS, IIS, URECA, and WHEALS). Exposures were (1) water damage/home dampness, dogs/cats at home, and dust mite allergen in the bed or bedroom during infancy/childhood, and (2) average ambient PM2.5 levels during the first three years of life. The self-reported history of water damage/home dampness and the presence of dogs and cats at home were collected by questionnaires. Dust mite allergen was measured by monoclonal antibody ELISA assays. We used previously validated predictive models to estimate the levels of PM2.5 at each participant’s residential address. The outcome was time to asthma diagnosis from age 1 month to 5 years. We applied Cox proportional hazards models using both indoor environmental exposure and PM2.5 as exposures and adjusting for both individual-level and neighborhood-level confounders.
Results: We included 6,300 children with birth years between 1987 and 2016. We found a detrimental association of water damage/home dampness in infancy/childhood and a protective association of dogs in the home in infancy with risk of childhood asthma regardless of PM2.5 adjustment. The independent effect of having both water damage/home dampness and high PM2.5 relative to not having either was strongly associated with asthma development (hazard ratio: 1.97 [95% confidence interval: 1.19–3.26). There were no significant associations with cats in the home or dust mites.
Conclusion: Our study demonstrated that both outdoor air pollutants and indoor exposures should be considered together as risk factors for asthma.