<http://schema.org/description>
"New research reports a high prevalence of vitamin D insufficiency and deficiency among patients with psoriatic arthritis. Seasonal variation in vitamin D levels was not observed in patients in southern or northern locations. The findings published today in Arthritis Care &amp;amp; Research, a journal of the American College of Rheumatology (ACR), also show no association between disease activity and vitamin D level."^^<http://www.w3.org/2001/XMLSchema#string>
<http://medicalxpress.com/news/2011-07-vitamin-d-insufficiency-prevalent-psoriatic.html>