DALLAS—Low vitamin D levels were associated with depressive symptoms, especially in people with a history of depression in a new study of more than 12,000 participants (Mayo Clin Proc. 2011 Nov;86(11):1050-5).
After conducting conducted a cross-sectional study of 12,594 participants at The Cooper Institute in Dallas from Nov. 27, 2006, to Oct. 4, 2010, UT Southwestern Medical Center researchers analyzed serum 25-hydroxyvitamin D [25(OH)D] levels. Depression was defined as a Center for Epidemiologic Studies Depression Scale (CES-D) score of 10 or more. Those with and those without a history of depression were analyzed separately.
In the total sample, higher vitamin D levels were associated with a significantly decreased risk of current depression based on CES-D scores. The finding was stronger in those with a prior history of depression, but not significant in those without a history of depression.
“Our findings suggest that screening for vitamin D levels in depressed patients–and perhaps screening for depression in people with low vitamin D levels–might be useful," said E. Sherwood Brown, professor of psychiatry and senior author of the study.
Previous studies from 2010 and 2008 found similar results.
However, he said they didn't find enough evidence to recommend vitamin D supplementation.
The scientists have not determined the exact relationship–whether low vitamin D contributes to symptoms of depression, whether depression itself contributes to lower vitamin D levels, or chemically how that happens. But vitamin D may affect neurotransmitters, inflammatory markers and other factors, which could help explain the relationship with depression, said Brown, who leads the psychoneuroendocrine research program at UT Southwestern.
