Racial Differences in the Oral Microbiome: Data from Low-Income Populations of African Ancestry and European Ancestry

Abstract

In this systemic investigation of racial differences in the oral microbiome using a large data set, we disclosed the significant differences in the oral microbial richness/evenness, as well as in the overall microbial composition, between African-Americans and European-Americans. We also found multiple oral bacterial taxa, including several preidentified oral pathogens, showing a significant different abundance or prevalence between African-Americans and European-Americans. Furthermore, these taxa were consistently found to be associated with the percentage of genetic African ancestry. Our findings warrant further research to understand how the racial difference in the oral microbiome influences the health disparity.

Ethnic variation of oral microbiota in children

“…Our study for the first time revealed the strikingly high prevalence of PI, lowest daily brush frequency and highest bacterial diversity for this understudied group. Our finding that African American had higher microbial diversity than Caucasians is consistent with a recent large cohort study showing that African American adults had a higher bacterial richness in oral washes than those from European ancestry 13 . By contrast, another study indicated that African American adults had the lowest bacterial diversity in subgingival plaques while Chinese and Caucasian adults had the highest diversity 14 .…”

“…In addition, our work represents the first study focused on the children's supragingival microbiome in different ethnicities. Previous studies have identified ethnicity-specific microbes in adults 13,14 . Our work highlights that the early oral microbiome had already exhibited ethnicity associated signature.…”

“…Several studies have investigated the oral microbiome difference among different ethnicities. In a large cohort study, 32 differential bacterial taxa were identified in oral rinse samples from adults with African ancestry and European ancestry 13 . In the same study, significantly higher microbial diversity was also found in the African ancestry group compared to the European ancestry group.…”

Elucidating the role of the gastrointestinal microbiota in racial and ethnic health disparities

“…The terms "race" and "ethnicity" likely encompass complex interactions of internal and external exposures that, in turn, affect gastrointestinal microbial composition. This is supported by accumulating evidence suggesting microbial differences by racial/ethnic group [9,10]. In an investigation of associations of ethnic background with fecal microbial composition among 2084 individuals living in Amsterdam, Netherlands, comprising 439 Dutch, 367 Ghanaian, 280 Moroccan, 197 Turk, 443 African Surinamese, and 358 South-Asian Surinamese participants, after adjustment for potential confounders, ethnicity was strongly associated with alpha diversity, beta diversity, and the relative abundances of certain taxa (e.g., Bacteroides) [9].…”

Functional Profiling of Saliva Microbiome is Essential for Oral Cancer Prediction

“…Besides, many genera/species found in the present study have not been previously reported, and vice versa. This inconsistency between studies could be attributed to the experimental design (e.g., sample types or hypervariable regions of the 16S rRNA gene [52]), the bioinformatics analysis pipeline (e.g., sequence denoising approaches [53] and reference databases [54]), the genetics of studied cohorts (e.g., racial factors [55]), and the complexity of oral carcinogenesis [56]. Alternatively, our results suggest that the inconsistencies may be due to the extremely high species turnover of oral ecosystems, and the dominance of the stochastic process in shaping microbial communities in saliva ( Fig.…”