Background: Although it is well known that patients with Parkinson's disease (PD) have low bone mineral density (BMD) and serum vitamin D level, there are no studies evaluating their relationship with the stage and clinical features of the PD.
Objective: The purpose of this study was to evaluate the relationship between BMD and serum vitamin D level and stage or clinical features of the PD.
Materials and methods: One hundred twenty-four patients with PD recruited from Movement Disorders Outpatient Clinic and age- and sex-matched 116 healthy controls were included in the study. BMD and serum vitamin D level of all participants were measured. After patients had been divided into four groups according to Hoehn and Yahr (H and Y) staging, a total of 5 groups with controls, BMD (lumbar and femoral) and serum vitamin D level were compared between groups. The relationship between the clinical features of the PD [disease duration, medication history, Unified Parkinson's Disease Rating Scale (UPDRS) part II and III, and subscores of UPDRS part III] and BMD or vitamin D was investigated.
Results: Lumbar and femoral BMD values and serum vitamin D level were significantly lower in patients with PD compared to controls. Low BMD and low serum vitamin D level were identified in the early stages of the disease (H and Y stage 1 and 1.5) and were marked by the progress of the stage of the disease. There was a negative relationship between the clinical features of the PD and both BMD and serum vitamin D level.
Conclusion: All patients with PD should be screened for developing osteoporosis and for sufficient vitamin D level in the early stages of the disease. Preventive methods for bone quality should be taken into consideration at the onset of PD.
Keywords: Bone mineral density; Hoehn and Yahr stage; Parkinson's disease; clinical characteristics; serum vitamin D.