Study abstract 2022
Air Pollutants and the Gut Microbiota and Metabolome During Early Life: Implications for Childhood Obesity
Elizabeth A. Holzhausen1, William B. Patterson1, Maximilian J. Bailey1, Howard H. Chang2, Donghai Liang2, Fred Lurmann3, Jeremy A. Sarnat2, Michael I. Goran4, Tanya L. Alderete1
1University of Colorado-Boulder, Boulder, CO, USA; 2Emory University, Atlanta, GA, USA; 3Sonoma Technology Inc., Petaluma, CA, USA; 4Children’s Hospital of Los Angeles, Los Angeles, CA, USA
Background. Early life near-roadway (NRAP) and ambient air pollution (AAP) exposure is associated with childhood obesity independent of poor diet and low physical activity. Other studies suggest that air pollution exposure may impact the gut microbiome, but this has not been examined in early life. This study aims to investigate whether air pollution exposures are associated with the infant gut microbiome, and whether early life air pollution exposure impacts infant growth trajectories via alterations to the gut microbiome.
Methods. Participants are from the ongoing Southern California Mother’s Milk Study, which includes detailed assessment of infant growth, the gut microbiota, and important covariates (e.g., sex, diet, socioeconomic status) at 1, 6, 12, 18, and 24 months post-partum. Our study is performing residential-based estimates of NRAP and AAP exposures (PM2.5, PM10, NO2) and measuring fecal metabolites as a readout of gut bacterial function. While follow-up is ongoing, available data has been used to examine associations between 1) newborn gut microbiota and measures of infant growth (n=132 infants); 2) air pollutant exposure and the composition of the newborn gut microbiota (n=103); and 3) prenatal air pollution exposure and infant growth trajectories (n=123).
Results. Infant gut bacterial diversity at 1 month predicted rapid growth in the first year of life (OR = 1.83; 95% CI:1.07,3.29), which is a strong predictor of childhood obesity (Alderete et. al. 2021). Additionally, AAP exposure in the first 6 months of life was associated with gut bacteria belonging to dominant phyla, including Bifidobacterium, Bacteroidetes, Firmicutes, and Proteobacteria at 6 months (in preparation). In addition, we observed that increased prenatal AAP exposure was associated with a faster rate of infant growth from 1 to 6 months of age, including infant weight and total subcutaneous fat (TSF) (Patterson et. al., 2021). Ongoing analysis is also examining the longitudinal associations between AAP and infant growth trajectories from 1 to 24 months of age.
Conclusions. To date, we have observed that the newborn gut microbiota predicts rapid infant growth during the first year of life. We have also found that increased AAP exposure during the first 6 months of life was associated with the gut microbiota at 6 months of age. Lastly, study results shown that prenatal AAP exposure was associated with a faster rate of infant growth in early life. Collectively, these findings provide early evidence that the gut microbiota may mediate the relationships between AAP exposure and infant growth. Future work in this cohort will examine the associations between ambient and NRAP exposures with infant growth trajectories as well as the composition and function of the gut microbiome during the first 24 months of life.