Number of teeth--a predictor of mortality in 70-year-old subjects

To investigate whether the number of teeth at age 70 is an independent predictor of mortality.

Within the gerontological population studies in Göteborg, Sweden, four birth cohorts born in 1901/1902, 1906/1907, 1911/1912 and 1922 were examined cross-sectionally at 70 years of age. The total number of participants in the odontological cohorts was 1803. Mortality data were collected from the national Swedish health registers. Cox regression models were used to measure the association between mortality and the number of teeth with adjustment for covariates such as health factors, socio-economic and lifestyle factors.

The prevalence of edentulism showed a marked change from 51% in the first cohort to 16% in the last cohort. The 7-year mortality rate was 14% in women and 28% in men, and the highest in edentulous men in the last two cohorts (42% and 47% respectively). The 7-year mortality including all four cohorts showed a hazard ratio of 0.96 (95% CI 0.94-0.98; P < 0.001) for the number of teeth with adjustment for cohort. The corresponding 18-year mortality including the three first cohorts showed a hazard ratio of 0.98 for women and 0.97 for men. The number of teeth was an independent statistically significant predictor of 7-year mortality in both genders and of 18-year mortality in men.

The result showed that each remaining tooth at age 70 decreased the 7-year mortality risk by 4%. The difference between edentulous subjects and dentate subjects with >or=20 teeth regarding 7-year mortality was significantly higher in the last compared to the first cohort. The number of teeth was a significant predictor of mortality independent of health factors, socio-economic status and lifestyle.