Study: Low levels of vitamin D linked to depression symptoms

DALLAS — Low levels of vitamin D have been linked to depression, according to UT Southwestern Medical Center psychiatrists working with the Cooper Center Longitudinal Study in a release issued Thursday.

This new study — published in Mayo Clinic Proceedings — helps clarify a debate that erupted after smaller studies produced conflicting results about the relationship between vitamin D and depression. Major depressive disorder affects nearly 1-in-10 adults in the United States.

“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,” stated Sherwood Brown, professor of psychiatry and senior author of the study, done in conjunction with the Cooper Institute in Dallas.

UT Southwestern researchers examined the results of almost 12,600 participants from late 2006 to late 2010. Brown and colleagues from the Cooper Institute found that higher vitamin D levels were associated with a significantly decreased risk of current depression, particularly among people with a prior history of depression.

Low vitamin D levels were associated with depressive symptoms, particularly in those with a history of depression, so primary care patients with a history of depression may be an important target for assessing vitamin D levels. The study did not address whether increasing vitamin D levels reduced depressive symptoms.

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 how that happens chemically. But vitamin D may affect neurotransmitters, inflammatory markers and other factors, which could help explain the relationship with depression, Brown said.

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