Vitamin D Lacking in Parkinson's Patients
Objective To examine the prevalence of vitamin D insufficiency in a cohort of untreated patients with early PD (diagnosed within 5 years of study entry).
Design, Setting, and Patients The Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) cohort is a well-characterized cohort of subjects with early, nondisabling PD. The cohort is well suited for examining the prevalence of vitamin D insufficiency early in the course of the disease. We conducted a survey study of vitamin D status in stored blood samples from patients with PD enrolled in the placebo group of the DATATOP trial. Samples from baseline visits and end point/final visits (mean [SD], 18.9 [13.1] months) were analyzed for 25-hydroxyvitamin D (25[OH]D) concentration in blinded fashion.
Main Outcome Measures The mean vitamin D concentration and the prevalence of vitamin D insufficiency at baseline and end point/final visits.
Results Among 199 subjects, 170 (85.4%) had samples from the baseline and end point visits available for analysis; 13 were excluded (10 with low probability of having PD and 3 with 25[OH]D concentrations >3 SDs above the mean). In the remaining 157 subjects, the mean (SD) 25(OH)D concentrations at the baseline and end point visits were 26.3 (8.6) ng/mL and 31.3 (9.0) ng/mL, respectively (to convert to nanomoles per liter, multiply by 2.496). The prevalence of vitamin D insufficiency (25[OH]D concentration <30.0 ng/mL) was 69.4% at baseline and 51.6% at the end point.
Conclusions The prevalence of vitamin D insufficiency in patients with early PD was similar to or higher than those reported in previous studies. Vitamin D concentrations did not decline during progression of PD. Further studies are needed to elucidate the natural history and significance of vitamin D insufficiency in PD.
From press release:
Patients with a recent onset of Parkinson disease have a high prevalence of vitamin D insufficiency, but vitamin D concentrations do not appear to decline during the progression of the disease, according to a report in the March issue of Archives of Neurology, one of the JAMA/Archives journals.
Vitamin D is now considered a hormone that regulates a number of physiological processes. "Vitamin D insufficiency has been associated with a variety of clinical disorders and chronic diseases, including impaired balance, decreased muscle strength, mood and cognitive dysfunction, autoimmune disorders such as multiple sclerosis and diabetes (types 1 and 2), and certain forms of cancer," the authors write as background information in the article. "Vitamin D insufficiency has been reported to be more common in patients with Parkinson disease (PD) than in healthy control subjects, but it is not clear whether having a chronic disease causing reduced mobility contributes to this relatively high prevalence."
Marian L. Evatt, M.D., M.S., of Emory University School of Medicine and the Atlanta Veterans Affairs Medical Center, and colleagues examined the prevalence of vitamin D insufficiency in untreated patients with early PD, diagnosed within five years of entry into the study. They conducted a survey study of vitamin D status in stored blood samples from patients with PD who were enrolled in the placebo group of the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) trial.
The authors found a high prevalence of vitamin D insufficiency and deficiency in 157 study participants with early, untreated PD. At the baseline visit, most study participants (69.4 percent) had vitamin D insufficiency and more than a quarter (26.1 percent) had vitamin D deficiency. "At the end point/final visit, these percentages fell to 51.6 percent and 7 percent, respectively."
"Contrary to our expectation that vitamin D levels might decrease over time because of disease-related inactivity and reduced sun exposure, vitamin D levels increased over the study period," the authors write. "These findings are consistent with the possibility that long-term insufficiency is present before the clinical manifestations of PD and may play a role in the pathogenesis of PD."
Vitamin D insufficiency in patients with early PD was similar or higher than the prevalence reported in previous studies.
"We confirm a high prevalence of vitamin D insufficiency in patients with recent onset of PD, during the early clinical stages in which patients do not require symptomatic therapy," the authors conclude. "Furthermore, vitamin D concentrations did not decrease but instead increased slightly over the course of follow-up. This provides evidence that during early PD, vitamin D concentrations do not decrease with disease progression."
Marian L. Evatt; Mahlon R. DeLong; Meena Kumari; Peggy Auinger; Michael P. McDermott; Vin Tangpricha; for the Parkinson Study Group DATATOP Investigators.
High Prevalence of Hypovitaminosis D Status in Patients With Early Parkinson Disease.
Emory University School of Medicine and the Atlanta Veterans Affairs Medical Center.