Effects of Phthalate Exposure on Oral Microbiome Diversity and Enrichment of Gemella and Streptococcus

Phthalates are endocrine-disrupting plasticizers widely used in consumer products, but their effects on oral microbiome diversity remain unclear. To examine associations between phthalate exposure and oral microbiome characteristics.

Data were obtained from the 2009 to 2012 cycles of the National Health and Nutrition Examination Survey. Oral microbiome diversity was assessed via 16S rRNA gene sequencing of oral rinse samples. Urinary phthalate metabolites were measured by high performance liquid chromatography-electrospray ionization-tandem mass spectrometry and normalized to uric creatinine. Three microbiome indices were evaluated: α-diversity, β-diversity, and relative abundance. Linear regression and Permutational Multivariate Analysis of Variancetest were employed to examine associations between phthalate exposure and α-diversity and microbial composition, and to assess differences in β-diversity across phthalate exposure tertiles.

Higher concentrations of mono (carboxyoctyl) phthalate (MCOP) and mono-isononyl phthalate (MiNP) were significantly associated with reduced α-diversity (Observed ASVs: β = -0.096 and -0.098; Faith's Phylogenetic Diversity: β = -0.097 and -0.092; Shannon-Weiner index: β = -0.109 and -0.126; Simpson Index: β = -0.078 and -0.110, respectively, with all P < .05). β-diversity, including Bray-Curtis dissimilarity, unweighted UniFrac distance, and weighted UniFrac distance, significantly differed across phthalate exposure tertiles for most phthalates, except for mono-n-butyl phthalate (MBP) and mono-isobutyl phthalate (MiBP). At the genus level, Mono (carboxynonyl) phthalate (MCNP) was positively associated with Gemella (β = 0.099, P = .026), and MiNP with Streptococcus (β = 0.089, P = .026).

Pphthalate exposure is associated with alterations in oral microbiome diversity and composition, highlighting potential microbiome-mediated pathways underlying phthalate-related health effects.

phthalate exposure alters oral microbiome diversity, suggesting a potential mechanism linking plasticizers to adverse health outcomes.