The Relationship Among Bone Mineral Density, Bone Biomarkers and Vitamin D Levels in Patients with Parkinson's Disease

BACKGROUND: Idiopathic Parkinson's disease (IPD) is the most common age-related neurodegenerative movement disorder. It causes a decrease and deceleration in movements. It may also lead to loss of bone mineral density, vi-tamin D deficiency, falls and fractures due to various factors. As indicated in our study, determining the prevalence of osteopenia and osteoporosis in IPD is important to determine complications. METHODS: Thirty patients with IPD and 30 age-matched control subjects were included in the study. The bone mineral density (BMD) measurements of the participants were taken from the lumbar spine (L1-4) and double femur regions using the dual energy X-ray absorptiometry device. Serum 25 (OH) vitamin D, alkaline phosphatase, parathormone, osteocalcin, prolidase and urine hydroxyproline levels were measured. RESULTS: The femur total BMD and serum 25 (OH) vitamin D levels were lower in the patients with IPD than in the control group (p > 0.05). The serum prolidase and urinary hydroxyproline levels were higher in the IPD group relative to the control group (p < 0.05). The frequency of osteoporosis and osteopenia was significantly higher in the IPD group than in the control group (p < 0.05). CONCLUSIONS: Patients with Parkinson's disease tend to have lower vitamin D levels than those with a similar age without Parkinson's disease. Vitamin D levels are usually associated with BMD in people with Parkinson's disease, but administering vitamin D does not improve BMD. Cross-sectional studies suggest a correlation between vitamin D levels and the severity of symptoms of Parkinson's disease. Decreased exposure to sunlight due to immobilisation and reduced vitamin D intake by diet may lead to vitamin D deficiency and low BMD. There is a negative correlation among the duration of disease, disease severity, number of falls, parathormone level and serum vitamin D level in people with Parkinson's disease. Consequently, vitamin D levels may be low in Parkinson's disease patients. Therefore, patients with Parkinson's disease should be checked for vitamin D and osteoporosis by considering the risk of hip fracture, fall from a height and high risk of osteoporosis.