A study published in the journal Translational Psychiatry reveals that targeted vitamin D supplementation in individuals with vitamin D deficiency may reduce the risk of probable lifetime major depression. Study: Vitamin D, chronic pain, and depression: linear and non-linear Mendelian randomization analyses . Image Credit: Aria Armoko / Shutterstock Vitamin D deficiency, defined as low blood levels of 25-hydroxyvitamin D, is known to trigger a state of chronic pain through its action on bone biology, immune responses, and inflammation.

Several observational study findings have highlighted an association of vitamin D deficiency with chronic pain, fibromyalgia, and depression. Randomized controlled clinical trials of vitamin D supplementation in patients with chronic pain have mostly produced mixed results. In contrast, systematic reviews of randomized trials have highlighted the positive impact of vitamin D supplementation on depression, depressive symptoms, and negative emotions.

Observational epidemiological studies can be associated with possible bias from confounding factors and reverse causality. Mendelian randomization can overcome these challenges. This method uses genetic variants as instrumental variables to determine the causal effect of an exposure on an outcome, providing a more accurate overview of any causal associations between vitamin D levels and chronic pain.

In Mendelian randomization analysis, genetic variants that are specifically associated with circulati.