Association between oral microbiome diversity and kidney stones: a cross-sectional study.

Background: Kidney stones are a common urologic disorder that imposes a significant burden on global public health. This study aimed to determine the association between oral microbiome diversity and kidney stones.

Methods: The data for this study came from the National Health and Nutrition Examination Survey 2009-2012 survey cycle. Use of alpha diversity to assess oral microbiome diversity. Multivariate logistic regression modeling was used to assess the association between different alpha-diversity indicators and kidney stones. Subgroup analyses and interaction tests were used to assess the stability of the association between alpha-diversity and kidney stones. Restricted cubic spline plots were used to assess non-linear associations and dose-response relationships.

Results: The study included 5,870 eligible participants with a mean age of 43.74 years at baseline. After adjusting for all covariates, the observed oral microbiome diversity was significantly negatively associated with the risk of kidney stones (P < 0.05). Subgroup analyses showed that oral microbiome diversity was negatively associated with the risk of kidney stones in certain populations, particularly among those aged 40-60 years, men, obese, with moderate to high cardiovascular health scores, smokers, and those without hypertension. Restricted cubic spline analysis suggested a significant non-linear negative correlation between the Shannon and Simpson diversity indices and the risk of kidney stones (p for non-linear < 0.05). Since our study was a cross-sectional design, the main limitation was the inability to prove causality.

Conclusions: In this study, we found an inverse relationship between oral microbiome diversity and kidney stone risk observed in alpha diversity. This reveals the complexity of host-microbiome interactions, and further mechanistic studies are necessary to elucidate these complex roles in the future.