Unrecognized vitamin D3 deficiency is common in Parkinson disease Harvard Biomarker Study

Objective: To conclusively test for a specific association between the biological marker 25-hydroxy-vitamin D 3 , a transcriptionally active hormone produced in human skin and liver, and the prevalence and severity of Parkinson disease (PD). Methods: We used liquid chromatography/tandem mass spectrometry to establish an association specifically between deficiency of 25-hydroxy-vitamin D 3 and PD in a cross-sectional and longitudinal case-control study of 388 patients (mean Hoehn and Yahr stage of 2.1 ± 0.6) and 283 control subjects free of neurologic disease nested in the Harvard Biomarker Study. Results: Plasma levels of 25-hydroxy-vitamin D 3 were associated with PD in both univariate and multivariate analyses with p values = 0.0034 and 0.047, respectively. Total 25-hydroxy-vitamin D levels, the traditional composite measure of endogenous and exogenous vitamin D, were deficient in 17.6% of patients with PD compared with 9.3% of controls. Low 25-hydroxy-vitamin D 3 as well as total 25-hydroxy-vitamin D levels were correlated with higher total Unified Parkinson’s Disease Rating Scale scores at baseline and during follow-up. Conclusions: Our study reveals an association between 25-hydroxy-vitamin D 3 and PD and suggests that thousands of patients with PD in North America alone may be vitamin D–deficient. This finding has immediate relevance for individual patients at risk of falls as well as public health, and warrants further investigation into the mechanism underlying this association.