Low Blood Levels Of Vitamin D May Be Associated With Depression In Older Adults: "ScienceDaily (May 6, 2008) — Older adults with low blood levels of vitamin D and high blood levels of a hormone secreted by the parathyroid glands may have a higher risk of depression, according to a new report .
About 13 percent of older individuals have symptoms of depression, and other researchers have speculated that vitamin D may be linked to depression and other psychiatric illnesses, according to background information in the article. '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 status,' the authors write. 'Moreover, poor vitamin D status causes an increase in serum parathyroid hormone levels.' Overactive parathyroid glands are frequently accompanied by symptoms of depression that disappear after treatment of the condition."