In this study, published in August 2020, researchers prospectively collected information on periodontal disease and tooth loss in participants in the Nurses’ Health Study (1992–2002) and the Health Professionals Follow-up Study (1992–2010). Then, they reviewed pathology reports from colonoscopies to establish the incidence of two types of colorectal neoplasms that often develop into colon cancer: serrated polyps and conventional adenomas. Removal of these lesions is associated with a reduced risk of colon cancer.
This study included 42,486 participants (17,904 women and 24,582 men). Over the past several decades, the participants had periodically reported information on gingivitis and tooth loss. The researchers then examined data on 84,714 person-endoscopies and documented 2,336 cases of serrated polyps and 4,102 cases of conventional adenomas.
Compared with people with no history of periodontal disease, those who had periodontal disease had a 17 percent increased relative risk of having a serrated polyp and an 11 percent increased risk of a conventional adenoma.
Interestingly, the researchers found that the loss of four or more teeth was associated with a 20 percent increased risk for having a serrated polyp. Also, among participants with periodontal disease, the researchers discovered that the more teeth lost, the higher the risk of advanced conventional adenomas.
For example, those who had periodontal disease and who had lost one to three teeth had a 28 percent higher chance of developing advanced conventional adenomas, while those who had periodontal disease and who had lost four or more teeth had a 36 percent higher chance.
The researchers indicated that the study sample was controlled for other known risk factors for colon cancer, including body mass index and level of physical activity. While smoking is a known cause of both periodontal disease and colorectal cancer, the researchers noted that even nonsmokers with tooth loss had higher rates of serrated polyps and conventional adenomas.
The researchers noted that the study’s limitations included the self-reporting of gingivitis and tooth loss and that most of the respondents were white, which may limit the validity of the results in more diverse populations.
However, the researchers concluded that the results of this study reinforce the importance of good oral health to ensure a healthy oral microbiome. “Our findings advance our understanding of the interplay between oral health, microbiome, and early colorectal carcinogenesis.”
Chun-Han Lo, et al. Periodontal Disease, Tooth Loss, and Risk of Serrated Polyps and Conventional Adenomas, Cancer Prevention Research, August 2020;13:699–706