Grade 1 vertebral fractures, bone mineral density, and the risk of fractures.

Abstract

To the Editor: We read with great interest the recent article by Johansson et al.(1) about grade 1 vertebral fractures (VFs) identified by vertebral fracture assessment (VFA) and the prediction of incident fractures in older women. We discuss several aspects of their article. First, the authors state that their work was the first to show that mild VF detected by VFA are predictive of new fractures. However, in 2019, we published(2) the results of our study finding that these prevalent mild vertebral deformities were associated with an increased risk of incident VF using VFA both at baseline and after follow-up (4.2 years) in a prospective cohort study. Indeed, other researchers have published different VFA-based approaches to describe the relationship between prevalent and incident VF.(3-5) Second, Johansson et al.(1) evaluated whether the association between prevalent grade 1 VF and the incidence of new fractures was independent of clinical risk factors and bone mineral density (BMD). The authors classified new fractures into three groups: any incident fracture, incident major osteoporotic fractures (MOFs), and incident VF. The authors highlighted that in the case of MOF, a Fracture Risk Assessment Tool (FRAX)-defined category, the incidence was independent of baseline BMD and clinical risk factors. However in the “any incident fracture” group, a not well defined category, the results were dependent of BMD and most notably in the incident VF subset, which are distinctive and site-specific osteoporotic fractures, both BMD and clinical risk factors were found to be associated. Furthermore, in our study, although the participating women were somewhat younger (mean age 66 years; 59–70 years at baseline) than those studied by Johansson et al.(1) (mean age 78 years) the incidence of VF was significantly associated with age and the prevalence of grade 1 VF as well as low BMD and a history of rheumatoid arthritis. Finally, the incidence of VF (6.6%) and the incidence rate (15.55 women/103 per year) that our group reported in 2019 were very similar to those depicted by Johansson et al.(1) in their present study. We believe that previously published studies such as ours and that reported by Johansson et al.(1) clearly support and strengthen the idea that grade 1 VF are predictors of new VF and that low BMD is an associated risk factor. However, with respect to the role of grade 1 VF and BMD in the development of other fragility fractures, the literature is not so conclusive.(6, 7) Last, we acknowledge that mild vertebral deformities or grade 1 VF are still an inconclusive radiological image category that can make clinical and therapeutic decisions a challenging matter.(8) The authors have no conflicts of interest or relationships to disclose. Eduard Kanterewicz: Conceptualization; formal analysis; investigation; writing-original draft; writing-review & editing. Emma Puigoriol: Investigation; methodology. Pilar Peris: Supervision; writing-review & editing.