ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microorganisms in Vertebrate Digestive Systems
This article is part of the Research TopicMicrobiome and its Roles in Disease Diagnosis and Treatment: Pathogen Resistance Spectrum, Metabolism, Risk Model, and Vaccine DesignView all 6 articles
Change of Oral Microbiome Diversity by Smoking Across Different Age Groups
Provisionally accepted
- 1College of Medicine, Seoul National University, Seoul, Republic of Korea
- 2Seoul Veterans Hospital, Gangdong-gu, Republic of Korea
- 3Seoul National University, Gwanak-gu, Republic of Korea
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
The oral microbiome, a complex ecosystem linked to both oral and systemic diseases, undergoes compositional and functional changes with aging. Tobacco exposure is a known disruptor of microbial homeostasis, yet its effect on microbial diversity remains inconsistent. Whether aging modifies the relationship between smoking and the oral microbiome remains unclear. This study aimed to evaluate (1) the association between serum cotinine and oral microbial diversity, (2) whether this association varies by age, and (3) taxonomic shifts that may explain smoking-related dysbiosis. We analyzed data from 4,387 adults aged 30-69 years in the U.S. National Health and Nutrition Examination Survey 2009-2012. Serum cotinine, an objective biomarker of nicotine exposure, was used as the primary exposure. Oral microbiome diversity was assessed via 16S rRNA gene sequencing of oral rinse samples. Microbial profiles were analyzed using observed amplicon sequence variants and Bray-Curtis. Alpha diversity declined progressively with age, with the most pronounced reduction among current smokers. Serum cotinine was inversely associated with alpha diversity, particularly in current smokers aged 60-69 years (adjusted β=-0.1081, p=0.0002). Beta diversity differed significantly by smoking status (PERMANOVA p<0.0001). Analysis identified 29 genera were associated with serum cotinine: Haemophilus, Neisseria, and Gemella decreased with higher exposure, while Atopobium and Lactobacillus increased. Tobacco exposure is associated with reduced oral microbial diversity, particularly in older adults. This highlights the synergistic impact of aging and smoking on the oral microbiome and underscores the need for age-specific prevention strategies. Prospective studies are warranted to confirm causality and assess the reversibility of smoking-induced dysbiosis.
Keywords: oral micro biome, Age specific, Cotinine, Smoking, Alpha diversity, beta diversity
Received: 27 Sep 2025; Accepted: 10 Nov 2025.
Copyright: © 2025 Seo, Min, Oh, Ryoo, Son, Lee and Min. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Kyoung-bok Min, minkb@snu.ac.kr
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.