Environmental Influences on the Early Life Gut Microbiome - Natural Experiment and Longitudinal Investigations

Event: International Society for Developmental Psychobiology 2023 Annual Meeting
Location: Utrecht, the Netherlands
Talk Abstract: Early life composition of the gut microbiome, the collection of microorganisms in the gastrointestinal tract, shapes health outcomes across the lifespan. Evidence suggests that early life gut microbiome development is sensitive to environmental influences (e.g., adversity, antibiotic exposure). However, research has been limited by a reliance on cross-sectional approaches (in the case of adversity) and observational studies of cohorts exposed to relatively similar conditions. I present two studies that leverage longitudinal and natural experiment designs to examine relations between environmental conditions and gut microbiome composition in early life. These include a longitudinal investigation on the relation between maternal postnatal internalizing symptoms and gut microbiome development from 3-24 months of age in N=100 infants living in Singapore, and a natural experiment leveraging the start of the COVID-19 pandemic to compare gut microbiome composition in N=20 twelve-month old infants living in New York City who were sampled before the start of the COVID-19 pandemic to N=34 infants who were sampled during the first year of the pandemic. In the longitudinal study, infants whose mothers reported clinically significant levels of internalizing symptoms showed a steeper increase in gut microbiome alpha diversity from 3 to 24 months of age than infants whose mothers did not. In the natural experiment study, infants sampled during the pandemic had lower alpha (community-level) diversity in the gut microbiome, as well as differential abundance of several taxa. Findings from these studies contribute novel evidence supporting the hypothesis that environmental conditions causally influence gut microbiome development in early life.