Association between vitamin D deficiency and major depression in patients with chronic kidney disease: a cohort study.

BACKGROUND: Patients with chronic kidney disease (CKD) have an elevated risk of both vitamin D deficiency (VDD) and depression. However, the relationship between VDD and the risk of depression in this population remains unclear. METHODS: Using the TriNetX network database (2010-2019), we conducted a propensity score-matched cohort study of CKD patients aged ≥50 years. Patients were categorized into VDD (≤20 ng/mL) and control (≥30 ng/mL) groups based on measurements within 3 months of CKD diagnosis. The primary outcome was the incidence of major depression within 1 year of follow-up. RESULTS: Among 17,955 matched pairs, VDD was associated with increased depression risk at 1 year (hazard ratio [HR]: 1.929; 95% confidence interval [CI]: 1.52-2.448; p < 0.0001). This association persisted through 3 years of follow-up. The relationship remained consistent across CKD stages, with similar risks in early (HR:1.977; 95% CI: 1.382-2.829) and CKD stage 3-5 (HR:1.981; 95% CI: 1.533-2.559). Males with VDD showed higher depression risk (HR: 2.264; 95% CI: 1.498-3.421) compared to females (HR:1.761; 95% CI: 1.307-2.374). Even vitamin D insufficiency (20-30 ng/mL) increased depression risk compared to normal levels (HR:1.667; 95% CI: 1.318-2.11). In patients with VDD, cerebrovascular disease, malnutrition, and ischemic heart disease are risk factors for depression. CONCLUSION: VDD is independently associated with increased depression risk in patients with CKD, particularly in males. These findings suggest that maintaining adequate vitamin D levels might be important for mental health in patients with CKD, although randomized trials are needed to confirm whether supplementation can prevent depression in this population.