# Using the Canadian Longitudinal Study on Aging to examine the association between tooth loss and hip bone mineral density

## TL;DR

This study explored if tooth loss is linked to hip bone density in older Canadians to help identify those at risk for osteoporosis.

## Contribution

The study reveals divergent associations between tooth loss and hip BMD in different bone mass categories.

## Key findings

- Tooth loss was not significantly associated with hip BMD in the overall sample.
- Fewer than 20 teeth were linked to lower hip BMD in those with low bone mass.
- Fewer than 20 teeth were associated with higher hip BMD in those with normal bone mass.

## Abstract

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).

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).

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).

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.