Vitamin D status and its association with season, depression in stroke

Vitamin D plays a key role in depression. In this study, we aimed to assess the prevalence of vitamin D deficiency or insufficiency and the association between vitamin D status and depression in patients with acute stroke.

From September 2013 to May 2015, consecutive patients with acute stroke were enrolled in this study within 7 days of symptom onset. Clinical information was collected during admission, and stroke severity was assessed at discharge. Depressive symptoms were measured by the 17-item Hamilton Rating Scale for Depression at 1 month after stroke. Based on the depressive symptoms, diagnoses of depression were made in accordance with DSM-IV criteria. Serum vitamin D levels were measured at admission. Binary logistic regression models were used to determine the association between depression and vitamin D levels treated as either absolute values (categorized as deficiency, insufficiency and sufficiency) or month-specific tertiles. Vitamin D levels were categorized by month-specific tertiles (high, intermediate, low) to reflect seasonal variation of serum vitamin D levels.

A total of 442 patients were enrolled in this study. The prevalence of vitamin D deficiency (< 30 nmol/L) or insufficiency (30-49.99 nmol/L) was 46%. The prevalence of vitamin D deficiency was significantly different in winter compared to summer months (p < 0.001). One hundred seven patients (26.6%) were diagnosed with depression at 1 month. In multivariable analyses, after fully adjusting for other potential confounders, the prevalence of depression was significantly higher in patients in the low tertile (odds ratio(OR) 2.24, 95% confidence interval (CI)1.18-4.26; p = 0.014) compared to the high tertile, and the prevalence of depression was also significantly higher in patients with vitamin D deficiency (OR 2.66, 95% CI 1.48-4.77; p = 0.001) and insufficiency (OR 1.93, 95% CI 1.00-3.74; p = 0.049) compared to those with vitamin D sufficiency.

Vitamin D deficiency and insufficiency occur at high rates in acute stroke patients. Low serum vitamin D levels were associated with depression in patients with acute stroke as analyzed by both the absolute level of vitamin D and month-specific tertiles. Intervention studies are needed to determine the benefits of vitamin D supplementation for depression in poststroke patients.