© BBCParkinson's gets progressively worse
Scientists are testing whether vitamin D supplements can ease symptoms of Parkinson's disease.
A US team found 55% of Parkinson's patients had insufficient levels of vitamin D, compared to 36% of healthy elderly people.
However, the Emory University researchers do not yet know if the vitamin deficiency is a cause or the result of having Parkinson's.
The study appears in the journal
Archives of Neurology.
Comment: There is also evidence that nicotine helps prevent the types of brain damage associated with Parkinson's disease.