Dutch researchers have said in a new study that low levels of vitamin D in elderly people may increase their risk of developing depression and other psychiatric problems.
"Underlying causes of vitamin D deficiency such as less sun exposure as a result of decreased outdoor activity, different housing or clothing habits and decreased vitamin intake may be secondary to depression, but depression may also be the consequence of poor vitamin D levels," the study said.
Researchers from Vrije Universiteit, Amsterdam, studied some 1,282 senior citizens aged between 65 and 95, and found 26 had major depression, while 169 suffered from minor depression.
Vitamin D levels were 14 percent lower in those elderly suffering from some kind of depression, according to the study published in the Archives of General Psychiatry.
It found that poor vitamin D status also led to an increase in levels of a hormone secreted by the parathyroid. Overactive parathyroid glands are frequently associated with depression.
The findings could be important in treating depression as both low blood vitamin D levels and high parathyroid hormone levels can be corrected by dietary and calcium supplements or increased exposure to sunlight.
"Moreover, the clinical relevance of the present study is underscored by our finding that 38.8 percent of men and 56.9 percent of women in our community-based cohort had an insufficient vitamin D status," the study added.
Further studies would now be needed to show whether changes in vitamin D levels came before or after depression.