Background: Sarcoidosis can involve bone both directly, through sarcoid disease localization, and indirectly, through a dysregulation of calcium and vitamin D metabolism as well as a side effect of steroid treatment.

Aim and objectives: This study aimed to investigate the prevalence of bone fractures and the relative risk factors in a large cohort of sarcoidosis patients.

Methods: We retrospectively enrolled 252 sarcoidosis patients (148 females, 54.7 ± 12.1 years) and sex-and age matched 250 healthy subjects as control group, followed at Siena University Hospital. We measured BMD at lumbar spine, at femoral neck and at total hip. Fragility fractures prevalence was collected through evaluation of all radiological data available. In the same day, patients had to perform complete lung function measurements, including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), FEV1/FVC, and diffusion capacity for carbon monoxide (DLCO), to be included.

Results:  BMD T-scores were lower in patients affected by sarcoidosis than in healthy controls, but the difference was statistically significant only for BMD-LS (p < 0.01) and BMD-TH (p < 0.05). Sarcoidosis patients showed a higher prevalence of fragility fracture (30.6 vs. 12.3%). Multiple regression analyses showed that BMI was positively associated with fragility fracture, while BMD-TH, DLCO(%) and therapy use was negatively associated.

Conclusion: sarcoidosis patients showed a significantly higher risk of fragility fractures than general population. Notably, the risk appeared to be related to the severity of pulmonary disease and maybe to disease activity, since steroid treatment was not related to fracture prevalence