INVERSE ASSOCIATION BETWEEN TOOTHBRUSHING AND UPPER AERODIGESTIVE TRACT CANCER RISK IN A JAPANESE POPULATION

Background. Oral hygiene is attracting increas- ing attention as a potential risk factor for cancers. To investi- gate the association between toothbrushing frequency and upper aerodigestive tract (UADT) cancer, the authors con- ducted a large-scale case-control study. Methods. A total of 856 UADT cancer case participants and 2696 age- and sex-matched control subjects without can- cer were included. Edentulous or participants with unknown frequency of toothbrushing or number of remaining teeth were excluded. Associations were assessed by odds ratios and 95% confidence intervals in logistic regression models with adjustment for potential confounders. Results. Compared with toothbrushing once per day, the adjusted odds ratio for brushing twice or more was 0.82 (95% confidence interval: 0.68, 0.99) whereas that for not brushing was 1.79 (0.79, 4.05). This association was observed especially in subjects who had a history of heavy smoking or drinking. Conclusions. The authors suggest that toothbrushing could have a protective effect for UADT cancer. V