The report, the first to describe cases in the United States of severe myopathy due to a lack of vitamin D, will appear in the April 24 issue of Archives of Internal Medicine. Paresh Dandona, professor of medicine and director of the Division of Endocrinology, Diabetes and Metabolism for UB and Kaleida Health, reports that five patients confined to wheelchairs because of severe muscle weakness regained normal muscle strength after four to six weeks of vitamin D supplementation. He has treated another five since the report was written.
Vitamin D is produced by the liver in the presence of sufficient calcium and sunlight.
Dandona said that myopathy due to vitamin D deficiency has been described for some time in the UK and Northern Europe, owing to the lack of sunshine in those regions. In the United States, vitamin D deficiency has only recently been appreciated, especially in the northern areas bordering Canada. We see vitamin D deficiency in the hospital setting and in the community at large during the winter months, but in this country, there are no reports of incapacitating muscle weakness associated with vitamin D deficiency. There is no data on how widespread this syndrome is in the U.S., but Dandona said it is likely quite common in the northern U.S. in persons who, for whatever reason, have little exposure to sunlight, and among those who live where there are long winters and limited sunlight. All patients were wheelchair-bound and complained of severe muscle pain, weakness and bone tenderness.