Abstract Body: Background and Aims:
The oral microbiome, comprising over 700 bacterial species along with a variety of viruses and other microbial taxa, is colonized as early as the prenatal period and is continuously shaped by various factors throughout life. While its primary role in maintaining oral health is well-recognized, recent studies suggest that the oral microbiome may also play a significant role in affecting systemic health condition, whereas the evidence from human studies is still lacking. We aimed to investigate whether oral microbiome alpha diversity was significantly related to premature mortality among U.S. adults.
Materials and Methods:
This study utilized data from 7,956 participants in the 2009–2010 and 2011–2012 cycles of the National Health and Nutrition Examination Survey (NHANES). Oral microbiome alpha diversity metrics, including observed Amplicon Sequence Variants (ASVs), Faith’s Phylogenetic Diversity, the Shannon-Weiner Index, and the Simpson Index, were calculated using microbial sequences obtained from oral rinse samples. Premature mortality was defined as death occurring before the age of 80 and was ascertained through linkage with the National Death Index till December 31, 2019.
Results:
During an average follow-up period of 8.84 years (SD: 1.54 years), 436 premature deaths (5.48%) were recorded among the 7,956 participants. After adjusting for demographic factors, smoking, alcohol drinking, and extra dental cleansing, higher alpha diversity metrics were significantly associated with a reduced hazard of premature mortality. Specifically, for each standard deviation increase, the HR were 0.81 (95% CI: 0.71–0.93) for observed ASVs, 0.82 (95% CI: 0.71–0.94) for Faith’s Phylogenetic Diversity, 0.83 (95% CI: 0.73–0.96) for the Shannon-Weiner Index, and 0.82 (95% CI: 0.72–0.95) for the Simpson Index. Adjustments for dietary factors attenuated these associations to be null.
Conclusion:
Our findings suggest that alpha diversity of the oral microbiome may be not a strong risk factor of premature mortality independently of dietary factors among U.S. adults.