Prevalence of Vitamin D Deficiency and Its Association With Anemia Severity in Anemic Patients: A Cross-Sectional Study

Background Vitamin D deficiency remains highly prevalent in India, even though the population is exposed to abundant sunlight throughout most of the year. However, data evaluating vitamin D status specifically among anemic adult populations in routine clinical settings remain limited. This study was undertaken to determine the prevalence of vitamin D deficiency in patients with anemia and to examine its relationship with hemoglobin concentration, the severity of anemia, and the underlying anemia subtype. Methods This cross-sectional, hospital-based observational study was conducted over six months in the department of general medicine at a tertiary care center in South India. A total of 246 anemic patients (hemoglobin 13 years were enrolled after obtaining informed consent. Demographic data, body mass index (BMI), sun exposure duration, skin type, and dietary vitamin D intake were recorded. Laboratory evaluation comprised measurement of hemoglobin concentration, serum ferritin, total iron-binding capacity (TIBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and serum 25-hydroxyvitamin D levels. Vitamin D status was defined based on serum 25-hydroxyvitamin D concentrations and categorized as deficient (