Race, Neighborhood Socioeconomic Status, and Gut Microbiome

Gut microbiome plays an increasingly recognized important role in human health. This study aims to evaluate the association among race, neighborhood disadvantage index (NDI), and gut microbiome in patients undergoing screening colonoscopy. Methods: The study includes 689 patients aged 50–80 years undergoing screening colonoscopy at University Hospitals Cleveland Medical Center. Each patient donated a stool sample 1–4 weeks prior to their colonoscopy examination. 16S ribosomal RNA genes in stools were sequenced and classified into 236 Operational Taxonomic Units (OTUs) to species level. Neighborhood Disadvantage Index (NDI) was derived from 17 variables reflecting neighborhood contextual environment. We first examined the association of race with microbiota, and race with NDI. We then examined further the association between NDI and each microbiota by linear mixed effect model to account for the correlation within census tract, with adjustment of age, sex, BMI, smoking, and sequencing batch. The significance of associations between microbiota and NDI are evaluated by likelihood ratio tests. Q-value was estimated for False Discovery Rate (FDR)-based multiple testing correction. For the microbiota associated with NDI with Q-value ⇐ 0.05, we additionally adjusted for genetic ancestry in the model in a subset of 222 patients who have available genome-wide ancestry informative SNP genotype data. Results: Of all the 172 microbiota that have minimum relative abundances >0.005, 13 microbiota were significantly associated with race. We speculate that such association with race could be at least partially driven by neighborhood socioeconomic environment, i.e., racialized neighborhood environment - given the high correlation of race and NDI (corr = 0.60, P = 3.38E-56). Multivariate-adjusted regression models showed that 5 microbiota were positively associated with NDI (Q-value