Age-Related and Lifestyle-Related Differences in Gut Microbiota Composition Among Community-Dwelling Adults

As global aging accelerates, identifying age- and lifestyle-associated gut microbiota alterations has become critical for understanding healthy aging and microbiota-targeted interventions. To explore the associations of age and lifestyle factors with gut microbiota profiles in community-dwelling adults, 159 Chongqing residents were divided into young (18–39, n = 44), middle-aged (40–59, n = 71) and elderly (60–89, n = 44) groups. Fecal samples were analyzed by 16S rRNA gene sequencing, and lifestyle factors were assessed using a study-specific structured questionnaire. The Shannon index differed significantly between the young and middle-aged groups (p < 0.05), whereas other α-diversity and β-diversity analyses showed no significant differences. Age-related shift trends included decreased Bacillota and increased abundance of Bacteroidota. Young adults were enriched in Parasutterella, the [Eubacterium] ventriosum group and Anaerostipes; middle-aged adults were enriched in Clostridium sensu stricto 4, Clostridium sensu stricto 1 and Holdemanella; and elderly adults were enriched in Prevotellaceae UCG-004, Helicobacter, Lactobacillus, Streptococcus and Fusobacterium. Lifestyle factors were independently associated with specific microbial signatures, including tea-related enrichment of Catenibacterium and Escherichia–Shigella, exercise-related enrichment of Dialister and Bavariicoccus, and milk-related enrichment of Bacillus and Klebsiella (formerly Raoultella). Overall, these findings provide population-based evidence linking age and lifestyle factors with gut microbial profiles and may inform microbiota-targeted strategies for healthy aging.