Abstract
INTRODUCTION: Given the care gap for osteoporosis among Canadians, in part due to barriers limiting access to a diagnostic bone density scan, this study investigated the association between number of teeth and bone mineral density (BMD) to help identify individuals at-risk of osteoporosis. The purpose of this study was to determine if an individual's number of teeth was associated with hip BMD in Canadian men and women aged 50-85 years using cross-sectional data from the Canadian Longitudinal Study on Aging (CLSA). METHODS: Eligible participants (n = 20,629) underwent an in-home questionnaire to collect responses including, number of teeth (< or ≥ 20 teeth), demographic variables (age, sex, ethnicity, body mass index, income) and lifestyle habits (current smoking status, physical activity level, diet). Hip BMD was measured using dual x-ray absorptiometry. The association between number of teeth (< or ≥ 20 teeth) and hip BMD was evaluated using a multiple linear regression with a post-hoc analysis by T-score categorization (normal bone mass, low bone mass, osteoporosis). RESULTS: Number of teeth was not significantly associated with an individual's hip BMD when adjusted for major risk factors associated with osteoporosis and oral health (age, sex, ethnicity, body mass index, current smoking status, income, physical activity level, and diet). However, varying results were observed when hip BMD was categorized by T-score. In participants with low bone mass, having fewer than 20 teeth was associated with lower hip BMD (P = 0.040). Whereas, having fewer than 20 teeth was associated with higher hip BMD in participants with normal bone mass (P < 0.001). No significant association between number of teeth and hip BMD was found in the osteoporosis group (P = 0.360). CONCLUSION: There was a lack of association between number of teeth and hip BMD in the combined study sample. The divergent associations seen for normal and low bone mass require further investigation. Whether including other indicators of oral health - in addition to number of teeth - can strengthen the ability to predict hip BMD with or without considering hip BMD status is an area of future study.