Role of the FKBP5 polymorphism rs1360780, age, sex, and type of surgery in weight loss after bariatric surgery: a follow-up study.

Background: Emerging evidence suggests that the FK506 binding protein 51 (FKBP5/FKBP51), encoded by the FKBP5 gene, influences weight and metabolic regulation. The T allele of a functional polymorphism in FKBP5 (rs1360780), has been associated with the expression of FKBP51 and weight loss after bariatric surgery.

Objective: To examine the role of the FKBP5 rs1360780 polymorphism in relation to age, sex, and type of surgery in weight loss after bariatric surgery in patients with severe obesity.

Setting: University Hospital in Spain METHODS: A cohort of 151 obese patients submitted to Roux-en-Y gastric bypass (62.3%) and sleeve gastrectomy (37.7%) were followed-up during 24-months (t; loss to follow-up: 0%). During the postoperative period body mass index (BMI) and percentage of excess and total weight loss were evaluated.

Results: The BMI analysis showed an effect of the interaction FKBP5 genotype by sex (P = .0004) and a tendency to the interaction genotype by surgery (P = .048), so that men carrying the T allele had higher BMI at t than those without the T allele, and T-allele carriers that underwent sleeve gastrectomy had higher BMI at t than the noncarriers. Additionally, we found an interaction between FKBP5 and age for the percentage of excess weight loss and BMI (P = .0005 and P = 1.5e-7, respectively), whereby individuals >48 years with the T allele displayed significant differences for the analyzed variables at t compared with the homozygotes for the alternate C allele showing lower weight loss.

Conclusion: FKBP5 rs1360780 genotype has specific effects on weight loss outcomes after bariatric surgery depending on sex, age, and type of surgery, suggesting worse results in older males carrying the T allele who have undergone sleeve gastrectomy.