Comparative Efficacy of Oral and Intramuscular Vitamin D Supplementation in Correcting Vitamin D Deficiency: A Randomized Clinical Trial

Despite significant progress in nutritional health, vitamin D deficiency remains a widespread and underdiagnosed public health concern. This randomized clinical trial evaluated the comparative efficacy of two standard treatment modalities for vitamin D deficiency: oral supplementation and intramuscular injection. A total of 277 patients diagnosed with vitamin D deficiency were recruited the Endocrinology and Rheumatology Clinic of Ayatollah Rouhani Hospital in Babol, Iran. Participants were randomly allocated into two intervention groups: Group A (n=142) received 50,000 IU of oral Cholecahciferol (vitamin D3) weekly for 8 weeks, while Group B (n=135) received a single intramuscular injection of 300,000 IU of vitamin D. Serum concentration of 25 hydroxyvitamin and calcium were measured at baseline and after the 8-week intervention. . Statistical analyses were performed using SPSS-20 software, with significance set at P < 0.05. The mean age of participants was 42.65 ± 14.24 in Group A and 44.80 ± 15.36 in Group B (P = 0.198) with females comprising 80.5% and 73.3% of the groups respectively (P = 0.138). Baseline serum 25(OH)D3 levels were similar in both groups: 13.62 ± 4.50 ng/ml in Group A and 13.35 ± 4.52 ng/ml in Group B (P = 0.594). Post treatment, serum 25(OH)D3 levels increased significantly in both groups, reaching 32.68 ± 14.16 ng/ml in Group A and 31.42 ± 14.10 ng/ml in Group B (P = 0.371). Baseline serum calcium levels were also comparable: 9.21 ± 0.49 ng/ml in Group A and 9.28 ± 0.54 ng/ml in Group B (P = 0.313). The findings illustrate that both oral and intramuscular vitamin D supplementation are equally effective in correcting vitamin D deficiency, with no significant differences in therapeutic outcomes. This suggests that either treatment approach can be effectively utilized in clinical practice, providing flexibility in managing this prevalent condition.