Serum 25-Hydroxyvitamin D Level Estimation among Patients with Parkinson's Disease in West Bengal, India, and its Relationship with Motor Impairment

Abstract

Context: Worldwide, the association of Vitamin D deficiency in Parkinson's disease (PD) has recently been proposed. However, to the best of our knowledge, such studies are lacking from eastern India. Aims: This study compares the prevalence of Vitamin D deficiency in a cohort of patients with PD with the prevalence in age-matched healthy controls. It also aimed at determining a significant correlation of the severity of the various motor manifestations in PD with low serum vitamin levels. Settings and Design: It was a prospective observational case–control study to estimate the level of serum 25-hydroxyvitamin D (25[OH] D) concentrations of the sample population. Subjects and Methods: One hundred consecutive PD patients were selected for this study between 2015 and 2018 from the patients attending neurology outpatient department. Control (n = 100) participants were randomly selected after matching for age sex, and geographic location. Statistical Analysis Used: Statistical Package for the Social Sciences version 15 with multivariate logistic regression (the Pearson correlation coefficient (r) and P value) was applied. Results: Among 100 PD patients 48, patients (48%) had Vitamin D deficiency, 34 patients (34%) had Vitamin D insufficiency, and 18 patients (18%) had normal Vitamin D level; whereas age- and sex-matched control population shows Vitamin D deficiency in 46% people, normal vitamin level in 42%, and insufficient Vitamin D level in 12% control population. The mean (standard deviation) 25(OH) D concentration in the PD cohort was significantly lower than in the control cohorts (20.72 [8.21] ng/mL vs. 25.56 [11.99] ng/mL, respectively; P = 0.001). There was major association between 25(OH) D levels and severity of motor scores (P = 0.028), tremor (P = 0.0001), bradykinesia (P = 0.001), and severity of freezing (P = 0.002), whereas no significant association was found between Vitamin D levels and rigidity (P = 0.05) and postural instability (P = 0.395). Conclusions: This study demonstrates a significantly higher prevalence of hypovitaminosis in PD versus healthy controls. The severity of motor scores, tremor, and bradykinesia and severity of freezing were found to have a direct inverse correlation with low serum Vitamin D levels which further emphasizes the provision of preventive and therapeutic supplementation of Vitamin D in PD.