Major Long-Term Study Confirms Link Between Vitamin D Deficiency And Depression

A large long-term study recently published in Mayo Clinic Proceedings confirms that there is a definite link between vitamin D deficiency and depression.

The University of Texas Southwestern study, which monitored over 12,500 people for a period of four years, concluded that low vitamin D levels are definitely associated with increased risk of depressive disorder. The study, which is of the largest and most comprehensive studies ever conducted on the association between low vitamin D and depression, confirms the finding of many small studies conducted over the past decade.

The researchers monitored primary care patients at The Cooper Institute in Dallas. The subjects were divided into two groups based on whether or not they had a prior history of depression. Data from tests that measured both current vitamin D levels and the presence and intensity of depressive symptoms indicated that higher levels of the vitamin corresponded with lower incidence of depression, while those with the lowest levels of the vitamin were at greatest risk for depression.

The association between blood levels of Vitamin D and the incidence of depression were most significant among patients who had a prior history of depression. Among these patients, high blood levels of the vitamin reduced the odds of depressive symptoms by about 10 percent.

The study authors said the exact nature of the relationship between vitamin D deficiency and depression remains unclear. Additional research is needed to determine whether deficiency leads to depression or depressive symptoms contribute to deficiency.

Previous research suggests that one of the roles Vitamin D plays in reducing the risk of depression is in its contribution to the healthy operation of neurotransmitters. In addition, maintaining adequate D vitamin levels is known to reduce the production of cytokines, proteins that increase inflammation. Previous research suggests that cytokines are a possible risk factor for depression.

The study results suggest that primary care patients who are currently depressed or have a history of depressive symptoms could benefit from screening for low blood levels of vitamin D.

Such screening is already commonly included in routine physical exams because low levels of the vitamin have been proven to be significant risk factors for a wide variety of medical problems, including cardiovascular disease, diabetes, autoimmune diseases, bone-related conditions such as osteoporosis, and neurological conditions including multiple sclerosis. Low vitamin D levels are also recognized as a risk factor for age-related conditions such as Alzheimer’s and Parkinson’s diseases.