Low vitamin D linked to eye disease

BUFFALO, N.Y., April 13 (UPI) -- Very low vitamin D blood concentrations are associated with increased odds of developing age-related macular degeneration, U.S. researchers say.

Lead author Amy E. Millen, assistant professor in the University at Buffalo School of Public Health and Health Professions, says vitamin D status was assessed using the blood measure of 25-hydroxyvitamin D or 25 (OH) D -- generally considered the means by which nutritional vitamin D status is defined.

"In women age 75 and younger, those who had 25-hydroxyvitamin D concentrations lower than 38 nanomoles per liter were more likely to have age-related macular degeneration -- the leading cause of blindness -- than women with concentrations greater than 38 nanomoles per liter," Millen says in a statement. "Blood concentrations above 38 nanomoles per liter were associated with at least a 44 percent decreased odds of having age-related macular degeneration."

The Institute of Medicine considers an adult with a blood 25 hydroxyvitamin D concentration of lower than 30 nanomoles per liter to be at increased risk of vitamin D deficiency and those with than 50 nanomoles per liter to be at increased risk for vitamin D inadequacy, Millen says.

However, having a higher vitamin D level than 38 nanomoles per liter does not appear to be more protective, Millen warns.

The finding is published in the Archives of Ophthalmology.