Research Assistant University of Minnesota University of Minnesota Minneapolis, Minnesota, United States
Background: Gut microbial communities (microbiomes) are involved in the development of healthy metabolism and immunity, thus highlighting the importance of identifying modulators of early-life microbiomes. This is of particular importance for women of color who tend to experience greater psychosocial stress stemming from discrimination and have a higher risk of adverse birth outcomes. Racial disparities in infant microbiome development remains unknown.
Objective: We investigated if infant and maternal race are associated with microbiome variation in a cohort of primarily exclusively breastfed infants.
Design/Methods: Healthy mother-infant dyads (n=115) were recruited as part of the Mothers and Infants Linked for Healthy Growth (MILk) study (NIH HD080444). Bacterial microbiomes were characterized for infant feces and maternal breastmilk at 1 month of infant age by sequencing 16S rDNA amplicons, aligning these to sequence databases for taxonomic identification, and computational analyses of biodiversity features using R software. Race was self-identified (by mothers) according to National Institutes of Health definitions (including identification with multiple races). Race was first categorized as Minority (20%) or White (80%), and then as Black or African American (8%), Minority Other (12%) and White (80%). P-values < 0.05 and false discovery rate corrected p-values (q) < 0.25 were considered significant.
Results: In breastmilk, species count was higher for Minority as compared to White mothers (Welch’s t-test, p < 0.05). With further race disaggregation, milk species count was higher for Black or African American as compared to White mothers but did not meet statistical significance (Welch’s t-test, p = 0.06), and there was no difference between Minority Other and White (Welch’s t-test, p </i>= 0.13). In infant feces, microbiomes differed by infant and maternal race when comparing both Minority/White and Black or African American/Minority Other/White (Beta-diversity, PERMANOVA, p < 0.05 for each race comparison). For all comparisons, race groups did not differ with respect to antibiotic exposure, birth mode, or infant sex (Fisher’s exact tests, p > 0.05). Conclusion(s): Self-identified race was associated with early-life microbiome variation in this pilot study. Further research is needed to understand the determinants of racial and ethnic disparities in early life microbiome development and the extent to which this may mediate future health outcomes. We postulate that the mechanism will be complex and include social, economic, and cultural factors.
Authors/Institutions: Abrielle Dillon, University of Minnesota, Minneapolis, Minnesota, United States; Sara Gonia, University of Minnesota, Minneapolis, Minnesota, United States; Timothy Heisel, University of Minnesota, Minneapolis, Minnesota, United States; Abigail Johnson, University of Minnesota, Minneapolis, Minnesota, United States; Dan Knights, University of Minnesota, Minneapolis, Minnesota, United States; Ellen W. Demerath, University of Minnesota, Minneapolis, Minnesota, United States; Cheryl A. Gale, University of Minnesota, Minneapolis, Minnesota, United States
