Human oral microbiome in aging: a systematic review

Objective: Studying aging and the risk factors associated with chronic non-communicable diseases is becoming increasingly relevant due to population aging and the progressive ageing of the older population itself. The most commonly studies risk factors include diet, physical exercise, cognitive activity and lifestyle habits in general. However, recent studies are starting to investigate how the oral microbiome can affect health and potentially contribute to the onset of a variety of chronic diseases. The aim of our study is to carry out a systematic review on the potential link between human oral microbiome and aging. Materials: This systematic review was carried out using the databases PubMed, the Cochrane Library, and Embase. Methods: The SR followed the Cochrane Handbook and the PRISMA statement. The included studies were qualitative assessed for risk of bias using Newcastle-Ottawa scale (NOS). Results: 3,490 records were identified, of which 6 met the inclusion/exclusion criteria. Discussion: Overall, it seems to emerge that the bacterial and fungal communities do not differ significantly in the observed populations except for the increase of periodontal pathogens in older subjects. Specifically, bacterial species richness and diversity (α-diversity) was found to decrease with age in most studies, whereas no age clustering (β-diversity) has been observed. Conclusion: In conclusion, studies provided valuable insights into the relationship between aging and changes in the oral microbiome. However, further studies are needed to address confounding factors, methodological differences, sample size limitations, and gender differences to further clarify how age-related changes in the composition of the oral microbiome may play a role in general health.