Lower Vitamin D Levels Are Associated With Depression in People With Chronic Spinal Cord Injury

Objectives To determine (1) whether the serum concentration of 25-hydroxy vitamin D (25(OH)D 3 ) was associated with depression levels in people with chronic spinal cord injury (SCI) and (2) whether any observed association was independent of potential confounders. Design Cross-sectional study. Setting Rehabilitation institute. Participants Patients with chronic SCI (N=100) recruited consecutively. Interventions Not applicable. Main Outcome Measures Patients underwent clinical and biochemical evaluations, including assessment of 25(OH)D 3 levels and the presence and severity of depressive symptoms, by using the interviewer-assisted self-report Beck Depression Inventory-II (BDI-II). Results Depression (BDI-II score ≥14) was observed in 15 of 28 women (53.6%) and 18 of 72 men (25.0%) of the study population. They exhibited significantly lower 25(OH)D 3 levels, lower functional independence degree in performing activities of daily living, poorer engagement in leisure time physical activity, and higher body mass index. Lower 25(OH)D 3 levels were associated with higher BDI-II scores as well as with the occurrence of depression. These associations persisted after adjustment for all significant predictors of the BDI-II score that were selected, as possible confounders, by univariate analysis. In receiver operating characteristic analysis, a 25(OH)D 3 level of Conclusions In people with chronic SCI, an inverse association exists between serum 25(OH)D 3 levels and depressive symptoms, widely independent of potential confounders, especially those, peculiar to this population, that can mediate the effects of depression on vitamin D levels.