Poor sleep quality, vitamin D deficiency and depression in the stroke population: A cohort study

Depression is a common psychiatric complication after stroke. However, the relationships among sleep quality, vitamin D status and depression are unclear in stroke patients. The aim of this study was to explore the impact of poor sleep quality and vitamin D status on post-stroke depression (PSD).In the present study, 233 stroke patients completed the one-month follow-up. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI) both at admission and 1 month after stroke. Depressive symptom was measured by the Hamilton Depression Scale (HAMD) at 1 month after stroke. Serum vitamin D levels were measured at admission. Multivariable logistic regression and mediation analysis were used to examine the mediating and moderating effects of sleep quality and vitamin D status on PSD.The incidence of PSD was higher in patients with poor sleep quality than those with good sleep quality. Vitamin D levels were negatively correlated with HAMD score (r = -0.244, P < 0.001). Prestroke poor sleep quality was associated with an increased risk of PSD in the vitamin D deficiency group after adjustment for potential confounders (OR = 4.047, 95%CI = 1.300-12.600, P = 0.016), while this association was not significant in the vitamin D sufficiency group. In mediation analysis, the relationship between vitamin D deficiency and PSD was mediated by poststroke sleep quality.Vitamin D levels were measured only at admission.The combination of poor sleep quality and vitamin D deficiency is associated with a substantially increased risk of PSD.