Vitamin D and depression in geriatric primary care patients

Vitamin D deficiency is common in the elderly. Vitamin D deficiency may affect the mood of people who are deficient. We investigated vitamin D status in older primary care patients and explored associations with depression.

A cross-sectional study was conducted and association analyses were performed. Primary care patients at a single academic medical center who were ≥60 years with serum total 25-hydroxyvitamin D (25[OH]D) levels were included in the analysis. The primary outcome was a diagnosis of depression. Frailty scores and medical comorbidity burden scores were collected as predictors.

There were 1618 patients with a mean age of 73.8 years (±8.48). The majority (81%) had optimal (≥25 ng/mL) 25(OH)D range, but 17% met mild-moderate (10-24 ng/mL) and 3% met severe (<10 ng/mL) deficiencies. Those with severe deficiency were older (P < 0.001), more frail (P < 0.001), had higher medical comorbidity burden (P < 0.001), and more frequent depression (P = 0.013). The 694 (43%) with depression had a lower 25(OH)D than the nondepressed group (32.7 vs 35.0, P = 0.002). 25(OH)D was negatively correlated with age (r = -0.070, P = 0.005), frailty (r = -0.113, P < 0.001), and medical comorbidity burden (r = -0.101, P < 0.001). A 25(OH)D level was correlated with depression (odds ratio = 0.990 and 95% confidence interval [CI] = 0.983-0.998, P = 0.012). Those with severe vitamin D deficiency were twice as likely to have depression (odds ratio = 2.093 with 95% CI 1.092-4.011, P = 0.026).

Vitamin D deficiency was present in a fifth of this older primary care population. Lower vitamin D levels were associated with depression. Those with severe deficiency were older and more likely had depression.