Background: The high variation in responses to bariatric surgery might be partially explained by genetic effects. Recently, common polymorphisms of the fat mass and obesity-associated gene (FTO) have been linked to obesity in some populations. Only two studies have investigated the effect of FTO variants on weight loss of morbid obese patients undergoing bariatric surgery with contradictory results.
Objective: We decided to investigate the role of the rs9939609 FTO gene polymorphism on outcomes after a biliopancreatic diversion surgery (BPD) in morbidly obese patients.
Design: A sample of 119 morbidly obese patients' body mass index (BMI) > 40 kg/m(2) were operated. Weight, fat mass, blood pressure, basal glucose, triacylglycerols, total cholesterol, low density lipoprotein cholesterol and high density lipoprotein cholesterol were measured at basal visit and at each visit (basal, 3, 9 and 12 months). The frequency of metabolic comorbidities was recorded at each visit.
Results: Thirty-seven patients (31.1%) had genotype TT (wild type group), 58 (48.7%) patients had genotype TA and 24 patients (20.2%) had genotype AA. In the wild and mutant type groups, BMI, weight, waist circumference, systolic blood pressure and diastolic blood pressure decreased in a significant way. In the wild type groups, glucose, total cholesterol, low density lipoprotein (LDL) cholesterol and triacylglycerol concentrations decreased at 3, 9 and 12 months after surgery. In the mutant type groups, glucose, total cholesterol and triacylglycerol concentrations decreased at 3, 9 and 12 months after surgery. LDL cholesterol decreased at 9 and 12 months after surgery. Initial weight percent loss at 3 months of follow-up was higher in the wild type group (26.1% vs. 18.6%: p < 0.05). The initial weight percent loss at 9 or 12 months was similar in both genotypes.
Conclusion: Our study showed a higher initial weight loss at 3 months after the TT variant of FTO gene (rs9939609). However, the weight loss at 9 and 12 months of BPD was similar in both genotypes with a significant improvement in biochemical parameters and cardiovascular comorbidities.