Parkinson's linked to vitamin D deficiency

A majority of Parkinson's disease patients had insufficient levels of vitamin D, according to a new study from the US Emory University School of Medicine published in the October issue of the Archives of Neurology. The retrospective study examined 100 people per group, who were recruited between 1992 and 2007. Every fifth Parkinson's patient from Emory's clinical neurology database was selected, then healthy controls and patients with Alzheimer's disease were matched on age and state of residence. The study compared PD sufferers to AD patients because the authors wanted to evaluate the possibility that neurodegenerative diseases in general lead to vitamin D insufficiency.

The fraction of PD patients with vitamin D insufficiency, 55%, was significantly more than subjects with AD (41%) or healthy elderly people (36%). In addition, the study found that the fraction of patients with the lowest levels of the nutrient, described as vitamin D deficiency, was higher (23%) in the PD group than the AD arm (16%) or the healthy cohort (10%).

It is possible the connection may not be related to the genesis or progression of the disease, but rather comes about because patients with PD have mobility problems and are seldom exposed to the sun, the study's authors say. However, they note that their study group did not come from a region where poor weather causes low levels of sunlight.