Key pointsSignificantly lower BMD in PD compared to healthy subjects in both genders.Less than 35 mg2/dl2 of Ca–P product in >80% of PD patients.Significant correlations between BMD and severity of PD.Lower BMD at H&Y stage III/IV than that at H&Y stage I/II.ObjectivesAlthough several lines of evidence have suggested that patients with Parkinson’s disease (PD) have a higher risk of osteoporosis and fracture, the association between bone mineral density (BMD) and severity of PD patients is unknown.MethodsWe performed a cross-sectional study of 54 patients with PD and 59 healthy age-matched controls. Multiple clinical scales were used to evaluate the severity of PD, and serum levels of calcium, phosphorus, and homocysteine were measured to determine BMD’s association with PD severity.ResultsBMD in PD patients was significantly lower than that in healthy controls. The BMD scores of the spine, femoral neck (FN), and hip were lower in females than in males in the healthy group. In the PD group, BMD in the hip was significantly lower in females compared to males. There was a negative correlation between daily l-DOPA dosage and BMD in the spine and hip in the PD group, while BMD in the spine, neck, and hip was significantly correlated with severity of PD. Besides, we found that among the lumbar spine (LS), FN, and hip, bone loss in the LS was the most severe in PD patients based on the T-scores.ConclusionOur findings support the hypothesis that patients with PD have a higher risk of osteoporosis, and that low BMD in the spine, FN, and hip may indirectly reflect the severity of PD. Our findings have prompted us to pay more attention to osteoporosis in the LS in Chinese PD patients.