Original article: integrated health Severe obesity and vitamin D deficiency treatment options before bariatric surgery: a randomized clinical trial Masoud Sayadi Shahraki, M.D. a , Noushin Khalili, M.D. b , Shadi Yousefvand, M.D. c , Erfan Sheikhbahaei c , Shahab Shahabi Shahmiri, M.D., M.P.H. d, * a Laparoscopic Surgery Fellowship, Department of Surgery, Isfahan University of Medical Sciences, Isfahan, Iran b Isfahan Endocrine and Metabolism Research Center, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran c Student Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran d Laparoscopic Surgery Fellowship, Department of Surgery, Isfahan Minimal Invasive Surgery and Obesity Research Center, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran Received 20 December 2018; accepted 21 May 2019 Abstract Background: Obesity, which has various complications and co-morbidities, is an epidemic issue worldwide. Vitamin D deficiency (VDD) is a well-known metabolic disorder among patients with se- vere obesity. While they are good candidates for bariatric surgery, this deficiency can affect the outcome of surgery negatively. Objectives: The aim of this study was to compare 3 different VDD treatment strategies for use before bariatric surgery and compare serum vitamin D levels after 7 weeks. Settings: University hospital, Isfahan, Iran. Methods: This was a single-blinded, randomized clinical trial on 100 patients who were referred for bariatric surgery from 2016 to 2018. Vitamin D (VitD) level was checked before surgery for the pa- tients included in the study, if their VitD level was ,30 ng/mL. We rechecked their serum VitD in the 8 th week, after 7 weeks of treatment. The participants were randomly allocated into 3 groups: 33 pa- tients were treated with 50,000 units VitD 3 capsules every week for 7 weeks; 33 patients were treated with a single dose of 300,000 units VitD 3 ampoule; and 34 patients were treated with a combination of a half of the injection dose, followed by the oral capsule for 4 weeks. Results: No case was lost during the follow-up time. No significant differences were found among the 3 groups in terms of their age (P 5 .654), body mass index (P 5 .434), sex (P 5 .799), initial 25(OH) VitD level (P 5 .273), and history of supplement use (P 5 .45). Mean serum VitD levels were 15.21, 13.16, and 13.37 ng/mL, respectively, before the surgery and reached 32.91, 24.74, and 29.49 ng/mL after 7 weeks of treatment in oral, injection, and combined groups, respectively. Finally, the 7-week oral treatment option had significantly higher levels of VitD (P value 5 .034). Conclusion: VDD treatment with 50,000 units VitD 3 capsule every week for 7 weeks before bariatric surgery yields a higher level of VitD. Based on our findings, injectable supplements are not recommen- ded for VDD treatment. (Surg Obes Relat Dis 2019;15:1604–1611.) Ó 2019 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved. Key words: Bariatric surgery; Obesity; Vitamin D deficiency; Vitamin D *Correspondence: Shahab Shahabi Shahmiri, M.D., M.P.H., Alzahra Uni- versity Hospital, Sofe Blvd., Isfahan, Iran. E-mail address: shshahabi@yahoo.com (S. Shahabi Shahmiri). https://doi.org/10.1016/j.soard.2019.05.033 1550-7289/Ó 2019 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved. Surgery for Obesity and Related Diseases 15 (2019) 1604–1611