Investigating the impact of COVID-19 lockdowns on fragility fracture risk and bone mineral density in a large observational cohort: a cross-sectional study.

Objectives: Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2 or COVID-19) led to lockdowns predisposing people to sedentary lifestyles and unhealthy behaviours which may have affected bone mineral density (BMD) and fragility fracture risk. However, limited studies describe such an association. We aimed to investigate how COVID-19 lockdowns has affected BMD and fragility fractures in a large cohort. Methods: Patients were referred to our DXA scanner from 2004 to 2024 and were subsequently categorized as pre- or post-March 23, 2020 (pre- and post-COVID-19) to allow analysis between the groups. Demographic, BMD and compositional data were compared between the two populations. A multivariate logistic regression modelled the odds of reporting a fracture including hip and non-hip fracture. A multiple linear regression was used to model how the lockdown has affected bone density. All analyses were adjusted for confounders. Results: Of 43 799 referrals, 6564 were post-COVID-19. Post-COVID-19 patients had higher non-hip fracture rates (42.0% vs 39.8%), were 3 kg heavier, and had lower left femoral T-scores. Patients referred post-COVID-19 had a statistically significant reduction of -0.23 to their T-score after adjusting for confounders as well as increased risk of getting diagnosed with osteoporosis [odds ratio (OR) 1.49, 95% CI 1.40-1.59]. Patients referred after the pandemic had a reduced odds of any fracture (OR 0.83, 95% CI 0.77-0.88), hip (OR 0.74, 95% CI 0.62-0.88) and non-hip fracture (OR 0.78, 95% CI 0.73-0.83). Conclusion: COVID-19 lockdowns may have negatively affected bone; however, this has not translated to an increased fracture risk in our study. Further research is needed with prospective cohorts to corroborate this risk.