BACKGROUND: In our previous study, higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and the vitamin D receptor (VDR) FokI CC genotype were associated with milder Parkinson disease (PD). OBJECTIVE: We evaluated whether vitamin D3 supplementation inhibits the progression of PD on the basis of patient VDR subgroups. DESIGN: Patients with PD (n = 114) were randomly … Continue reading Vitamin D3 supplementation may stabilize PD for a short period in patients with FokI TT or CT genotypes without triggering hypercalcemia.