Determinants of pediatric healthcare utilisation and medication use: environmental and microbiome associations

Early-life exposures shape children's health and contribute to healthcare burden. Yet integrative analysis of early-life exposures associated with healthcare use is understudied. I organised reasons for medication use and unscheduled doctor visits from the CHILD Cohort (N=3263), a Canadian population-based prospective cohort, with SNOMED CT ontologies, and further identified exposures associated with high and low healthcare use, from pregnancy to age 5. Fever, bad cold, and ear infection were the most common reasons for unscheduled care. An exposome-wide association study of 2,877 exposures identified 39 FDR-significant associations with high healthcare utilisation, including cleaning product, nutritional, and air quality exposures. Microbiome diversity was also examined, given its role in health; alpha diversity did not associate with cumulative utilisation at three-months or one-year. However, higher three-month Shannon diversity was associated with reduced odds of a fever visit at six months. Findings could guide future studies of modifiable factors to reduce healthcare burden.