Periodontitis in a Large Cohort of Young Chinese Adults: Associated Factors and Salivary Microbiome–Metabolome Profiles

Abstract

Introduction and aims Periodontitis is a chronic multifactorial inflammatory disease that damages periodontal tissues and is associated with systemic diseases. It shows a global younger onset trend, with rising incidence in Chinese young adults, but studies mostly focus on those ≥35 years, lacking systematic exploration of 18 to 35-year-olds. Methods From December 2024 to May 2025, 2888 adults aged 18 to 35 years were recruited from Tongji Hospital. Periodontitis was diagnosed per the 2018 Classification. Questionnaires collected demographic, physical and mental health, oral hygiene and lifestyle data. Saliva samples underwent 16S rRNA sequencing and untargeted metabolomics. Statistical analyses included independent samples t-test, Mann-Whitney U test, chi-square test and binary logistic regression. Results Periodontitis prevalence was 25.00%. Logistic regression identified marital status, suboptimal health, adverse childhood experiences, smoking and alcohol drinking were correlated with periodontitis, while longer per-brushing duration was negatively correlated with periodontitis. Salivary microbiota community richness and composition differed significantly between groups, with higher Fusobacteriota in periodontitis patients. Untargeted metabolomics identified 267 differential metabolites (mainly lipids, amino acids) and enriched metabolic pathways (e.g., nucleotide metabolism). Fusobacteriota was negatively correlated with 5-phosphoribosyl-4-carboxy-5 aminoimidazole. Conclusions Multiple factors were associated with periodontitis in young adults. Salivary microbiota and metabolic abnormalities may be associated with its pathogenesis, providing a scientific basis for prevention and management. The generalizability of these findings was limited by single-center convenience sampling and exploratory multi-omics profiling performed on a small matched subgroup. Clinical relevance This study identified a 25% prevalence of periodontitis in Chinese young adults aged 18 to 35 years, clarified its multidimensional associated factors, and revealed salivary microbiome–metabolome perturbations. It provided a scientific basis for the prevention of periodontitis in this young population.