A Novel Approach to Examining Multiple Indoor Exposures in Early Childhood on the Inflammatory Pathway and Risk of Intermediate Outcomes for Childhood Asthma in the Canadian Healthy Infant Longitudinal Development (CHILD) Birth Cohort

Rationale: Oxidizing chemicals found in the indoor environment, particularly consumer products, can cause inflammation leading to respiratory illness. The CHILD birth cohort is a national study examining how environmental exposures interact with genetics, immune system, microbiome and other personal characteristics to impact the risk of developing asthma and allergies.Methods: 2700 of 3,455 children born into the CHILD cohort were included in this analysis. A comprehensive suite of indoor exposures with potential inflammatory properties (e.g. mold and moisture, cleaning products and other household chemicals, and pests) in infancy were combined into an Indoor Environmental Exposure Index (IEEI). Exposures were evaluated against asthma-related outcomes of recurrent wheeze, atopy and diagnosed asthma at age 3 years.Results: In logistic regression (adjusted for sex, parental atopy, income, ethnicity, and tobacco exposure) the IEEI at age 3 months was associated with a significantly higher risk of asthma and ...