Identifying individuals at risk of fragility fractures in a dental setting

Introduction: The increasing life expectancy is only positive if the added years are healthy years. Fragility fractures are most common in older adults, and they can result in lowered quality of life and high costs for the society. About one-half of Swedish women and one-fourth of the men are expected to sustain at least one fragility fracture during their lifetime, so identifying the high-risk individuals would be favorable.

Regular dental check-ups offer a possibility to identify individuals with a high risk of having a disease or condition outside the oral cavity. Features of the mandibular bone shown on dental radiographs have been found to reflect the bone density of the skeleton. Low Bone Mineral Density (BMD) is a risk factor for fragility fractures. Low physical performance is also a risk factor as a fall often precedes a fracture. FRAX is a tool commonly used in primary care to assess the ten-year risk of sustaining a fragility fracture.

Aim: The aim of the thesis was to study different methods of identifying individuals with a high risk of fragility fracture, methods that could be used in a dental setting.

Material and methods: In the first three studies, we used the unique REBUS cohort, a stratified random sample of the Stockholm population, where 32,183 men and women between the ages of 18-65 received a postal questionnaire in 1969-70. A smaller sample of the cohort had a dental assessment including intraoral radiographs. We acquired data concerning fractures during 1970-2016 from the National Patient Register. In study I, we assessed the trabecular pattern of mandibular bone in intraoral radiographs with two methods, one visual, and one semi-automated. We followed 837 individuals 18-65 years old for 47 years. In study II, we studied the association between questions of physical health and mobility for 16,766 participants 26-65 years, and hip fractures during 20-35 years of follow-up. In study III, we studied the association between questions about alcohol consumption for 27,766 participants, 18-65 years old, and hip fractures during 47 years of follow-up. We also studied diagnoses indicating high alcohol consumption before a fracture and the relationship to hip fractures. In study IV, a qualitative study, we interviewed patients at the Stockholm Public Dental Services about their thoughts about doing a FRAX assessment of ten-year fracture risk in a dental setting.

Results: In study I, we found no fracture predictive value in the two methods of assessing the trabecular pattern of the mandibular bone. In study II, questions of physical health and mobility could predict a 2.69 (CI 1.85-3.90) – 3.30 (CI 1.51-7.23) increase in hip fractures. This was true for all men, 26-65 years old at the study start and followed for 20-35 years until they were 61-85 years old, but for women only for those who were 26-45 years old and followed for 35 years, until 61-80 years old. In study III, the questions about alcohol consumption had no fracture predictive value. A hospitalization event with a diagnosis indicating high levels of alcohol consumption resulted in a significantly elevated subhazard ratio (SHR) for hip fractures in men (3.29, CI 1.80-5.98) and women (2.73, CI 1.37-5.42), but only in the youngest age group who were age 18-25 at the start of the study and 65-72 years old at the end of the study. This was interpreted as an indication that high alcohol consumption has a predictive ability for hip fractures that occur at an early age, for both men and women. In study IV, the interviewed participants were mostly positive about doing a FRAX assessment of the ten-year fracture risk, but they expressed concerns that need to be considered before introducing FRAX in a dental setting.

Conclusion: We found no evidence of fracture predictive ability using the semi-automated method. The visual method may not be suitable to use for all ages and both sexes. Questions about physical health and mobility, and high alcohol consumption need to be further developed and studied. Using FRAX may be a feasible way to identify high fracture risk, but further studies are needed.

List of scientific papers

I. Two methods of evaluating mandibular trabecular pattern in intraoral radiographs and the association to fragility fractures during a 47-year follow up. Elleby C, Skott P, Jonasson G, Theobald H, Nyrén S, Salminen H. Eur J Oral Sci. 2021;129(5):e1280.
https://doi.org/10.1111/eos.12801

II. Long term association of hip fractures by questions of physical health in a cohort of men and women. Elleby C, Skott P, Johansson SE, Nyrén S, Theobald H, Salminen H. PLoS One. 2023 Mar 29;18(3):e0283564.
https://doi.org/10.1371/journal.pone.0283564

III. The association between long term high alcohol consumption and hip fractures by sex. Elleby C, Skott P, Johansson SE, Nyrén S, Theobald H, Salminen H. [Submitted]

IV. Patients’ thoughts about assessment of fracture risk in a dental setting using FRAX—a qualitative interview study. Elleby, C., Skott, P., Theobald, H., Nyrén, S., & Salminen, H. Arch Osteoporos. 18(1):65.
https://doi.org/10.1007/s11657-023-01259-1