Long-term effects of smoking on tooth loss after cessation among middle-aged Finnish adults: the Northern Finland Birth Cohort 1966 Study

Background: Despite smoking cessation efforts, cigarette smoking remains a serious general and oral health problem. We aimed to investigate the putative benefits of smoking cessation on dentition and to analyse whether the time elapsed since smoking cessation associated positively with the remaining number of teeth. Methods: This cross-sectional study analyses data from the 46-year follow-up of the Northern Finland Birth Cohort Study 1966 (NFBC1966). A total of 5 540 subjects participated in this cross-sectional study, which utilises both clinical dental examinations and mailed questionnaires. We used the following information on smoking: status (current, former, never), years of smoking (current, former) and years elapsed since smoking cessation (former). Self-reported and clinically measured number of teeth (including third molars) served as alternative outcomes. We used binary logistic regression models to analyse the dichotomised number of teeth ('0-27', '28-32') and then calculated unadjusted and adjusted odds ratios (OR) with 95 % confidence intervals (CI) for the smoking variables (never smoker as the reference). Gender, education, tooth brushing frequency, diabetes and alcohol use served as confounders for the adjusted models. Results: Ten years or more of smoking associated with tooth loss; this effect was the strongest among men who reported having an ongoing smoking habit (self-reported outcome: adjusted OR = 1.74, CI = 1.40-2.16) and the weakest among women classified as former smokers (self-reported outcome: adjusted OR = 1.27, CI = 1.00-1.62). Conclusions: This study shows that smoking has long-term effects on tooth loss even after cessation. The findings support smoking cessation efforts to reduce oral health risks.