Surgery for Obesity and Related Diseases ] (2017) 00–00 Original article The Q1 Q2 relation between pro-oxidant antioxidant balance and glycolipid profile, 6 months after gastric bypass surgery Vahideh Bana Q3 zadeh a , Mohsen Nematy a , Majid Ghayour Mobarhan b , Shima Tavallaieb d , Habibollah Esmaili c , Ali Jangjoo d, * a Department of Nutritional Sciences, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran b Metabolic Syndrome Research Center, Faculty of Medicine, Mashhad University of Medical Science, Mashhad, Iran c Department of Biostatistics and Epidemiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran d Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Received July 18, 2017; accepted December 3, 2017 Abstract Background: Morbid obesity is a chronic disease that contributes to increased oxidative stress. Gastric bypass surgery is the gold standard method in treating co-morbidities. Objectives: The objective of this study was to evaluate the relation between pro-oxidant anti- oxidant balance (PAB) as one measure of oxidative stress and glycolipid profile 6 months after gastric bypass surgery. Setting: Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Methods: Thirty-five morbidly obese patients with body mass index ≥35 kg/m 2 with co-morbid- ities or ≤40 kg/m 2 were randomly recruited. The PAB assay was used to estimate oxidative stress. Anthropometrics and glycolipid profile were collected at recruitment and 6 months after surgery. Statistical analysis was performed using SPSS 16 software. Results: The study showed a significant postoperative reduction in serum PAB values compared with the baseline (P o .001). All anthropometric and several glycolipid parameters significantly reduced after surgery (P o .001), while serum high-density lipoprotein cholesterol was unaffected. Repeated measures analysis of variance showed that postoperative PAB values were affected by gastric bypass surgery (F ¼ 12.51, P ¼ .001). Regression analysis demonstrated medication usage controlling co-morbidities ( ^ β ¼ -.6, P ¼ .002) and fasting blood glucose ( ^ β ¼ .41, P ¼ .04) as independent factors in predicting PAB values 6 months after surgery. Conclusions: Gastric bypass surgery can reduce PAB values in favor of antioxidants 6 months after the operation. Accordingly, fasting blood glucose after gastric bypass surgery can be an independent factor in predicting PAB values. (Surg Obes Relat Dis 2017;]:00–00.) r 2017 American Society for Metabolic and Bariatric Surgery. All rights reserved. Keywords: Obesity; Morbid; Oxidative stress; Gastric bypass; Pro-oxidant antioxidant balance The prevalence of obesity and its complications are globally increasing [1]. Extreme or class III obesity is a chronic disease with a body mass index (BMI) ≥40 or ≥35 kg/m 2 with co-morbidities, in which gastric bypass surgery is the gold standard treatment method [2]. According to the World Health Organization's report in 2015, while nearly 28% of adults were obese worldwide, approximately 26% of the Iranian adult population suffered from obesity [3]. Although oxidative stress can be a consequence of obesity, it can also be a trigger of obesity 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 https://doi.org/10.1016/j.soard.2017.12.002 1550-7289/ r 2017 American Society for Metabolic and Bariatric Surgery. All rights reserved. This study was supported by the Vice Chancellor for Research of Mashhad University of Medical Sciences (940495). * Correspondence: Ali Jangjoo, Surgical Oncology Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. E-mail: JangjooA@mums.ac.ir