DesignCohort studyCohort selectionParticipants were recruited between 1994 and 1998 from the general population with the preferred ages of 35 to 65 years in women and 40 to 65 years in men.Exposure measurementSmoking was assessed using a questionnaire from which pack years of smoking were calculated. Educational attainment, body mass index, hypertension, diabetes, alcohol consumption and vitamin or mineral supplements were assessed from measurements and questionnaires. Tooth loss was also assessed by questionnaire returned between 2004 and 2006. With the exception of the tooth loss data analysis was based on data collected at baseline.Data analysisThe 24,373 participants who returned the tooth loss questionnaire were analysed. Two hundred and eighty-six (1.2%) were excluded, as they did not respond to either of the tooth loss questions, and an additional 106 (0.4%) were excluded because they gave inconsistent responses to the questions on tooth loss. Four hundred and thirteen (1.7%) participants with missing data on cigarette smoking and 192 (0.8%) participants with missing data in any of the covariates were also excluded. The association between smoking and number of teeth at baseline was assessed using negative binomial regression models to obtain relative risks and 95% confidence intervals (CIs).ResultsThe sample of 23,376 included 9,032 men and 14,344 women of which 4,394 (19%) were current cigarette smokers, and 7,268 (31%) were cigarette smokers. 1,566 (6.7%) were edentulous at baseline. Compared with never smokers, current smokers were more likely to be male, less educated, more likely to be hypertensive, and less likely to take vitamins/mineral supplements, and they had higher alcohol consumption. Cigarette smoking was associated with higher prevalence of tooth loss at baseline as well as higher incidence of tooth loss during follow-up. The association between cigarette smoking and incident tooth loss during follow-up for the fully adjusted model (adjusted for age, sex, education, diabetes, body mass index, waist-to-hip ratio, hormone replacement therapy, contraception, intake of vitamin and mineral supplements, physical activity, alcohol intake, hypertension, and cardiovascular disease) is shown in the table.ConclusionsThere is a strong dose-dependent association between cigarette smoking and the risk of tooth loss. The risk declines after cessation of cigarette smoking; however, the risk may remain elevated for up to 20 years compared with never smokers. Efforts to improve the oral health of the population should include the prevention of smoking as well the promotion of smoking cessation.