Influence of betel nut chewing on oral microbiome in Papua New Guinea.

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.