BACKGROUND AND OBJECTIVES: For thousands of years, betel nut has been used as a psychoactive agent in Asian and Oceanian populations. Betel nut chewing was associated with the alteration of human oral microbiome and with diseases such as oral cancer and periodontitis, but only in populations of Asian cultural background. We studied the influence of betel nut chewing on the oral microbiome in Papua New Guinea, where half of the population uses betel nut and the prevalence of these diseases is one of the highest in the world. METHODOLOGY: We characterized the oral microbiomes of 100 Papua New Guineans. We defined two cohorts of betel chewers (n = 50) and non-chewers (n = 50) based on a genetic approach to identify the presence of betel nut in saliva. We statistically compared the alpha and beta microbial diversities between the two cohorts. We performed linear discriminant analyses to identify bacterial species more prevalent in each cohort. RESULTS: We found that oral microbial diversity is significantly different between betel chewers and non-chewers. The dysbiosis observed in betel chewers, led to an increase of pathogenic bacterial species including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, known to be in the aetiology of periodontal diseases. CONCLUSIONS AND IMPLICATIONS: Our study strongly supports the alteration of human oral microbiome by betel nut use, potentially leading to periodontal diseases. It also shows the need to consider local specificities (e.g. different habits, betel nut types, and oral microbial diversities) to better characterize the impact of betel nut chewing on health.

ARC Centre of Excellence for Australian Biodiversity and Heritage University of Wollongong Wollongong New South Wales 2522 Australia

Biology Centre Czech Academy of Sciences 37011 Ceske Budejovice Czech Republic

Centre de Recherche sur la Biodiversité et l'Environnement Toulouse France

College of Arts Society and Education James Cook University P O Box 6811 Cairns Queensland 4870 Australia

New Guinea Binatang Research Centre PO Box 604 511 Madang Papua New Guinea

Strand of Anthropology Sociology and Archaeology School of Humanities and Social Sciences University of Papua New Guinea PO Box 320 University 134 National Capital District Papua New Guinea

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