Tooth loss and risk of hip fracture: a prospective study of male Japanese dentists

Objectives To determine whether the number of teeth lost can predict the risk of subsequent hip fracture. Methods We followed up 9992 male Japanese dentists aged 50 years or more (mean age ± standard deviation [SD], 61.1 ± 9.6 years) for incidence of hip fracture. From 2001 through 2006, they completed a baseline questionnaire on lifestyle and health factors including the number of teeth lost (excluding third molars). Incidence rate ratios (IRRs) were estimated by fitting proportional hazard models. Results During the mean follow-up period of 6.0 years, 20 new cases of hip fracture occurred. Participants who had lost 15 or more teeth at baseline were at a significantly increased risk of hip fracture: the multivariate-adjusted IRRs were 4.1 (95% confidence interval [CI], 1.2–14.2) for loss of 15–27 teeth and 4.5 (1.1–18.0) for edentulousness relative to loss of 0–14 teeth (trend P, 0.028). Overall, the risk of hip fracture was weakly associated with the number of teeth lost: the IRR per tooth was 1.06 (95% CI, 1.01–1.12). Conclusions Tooth loss was slightly associated with a higher risk of subsequent hip fracture. The number of teeth lost might be informative in predicting this risk.