Effect of eight polymorphisms on weight loss outcomes in overweight/obese caucasian adults

Abstract

Introduction: Genetic screening to improve/personalize obesity treatment outcomes is available on the market despite the lack of conclusive evidence in this regard. The aim of this study was to investigate the association between genotype (eight polymorphisms) and weight loss outcomes following a weight loss programme. Methods: N=88 adult volunteers (BMI>27 kg/m2) participated in a six-month conservative weight loss programme that included dietary, physical activity and behavioral components. SNPs investigated: FABP2 Ala54Thr, INSIG2 rs7566605, FTO rs1421085, FTO rs17817449, ADRB3 Trp64Arg, ADRB2 Arg16Gly, GNB3 C825T, PPAR 2 Pro12Ala. Baseline and follow-up life-style assessments included physical activity, general psychological health (GHQ), selfesteem, depression and eating behaviour (restraint, disinhibition and hunger). Statistical analyses involved mixed effects linear models that were adjusted for gender and compliance to the weight loss programme. Results: The mean weight loss over six-months was 7.8 kg or 8.6%. Mutant Gly16Gly subjects of ADRB2 lost less weight (p=0.0087) over the first month. Subjects with a mutant Gly16-allele and mutant C-allele of INSIG rs7566605 lost less weight over six months than other allelic combinations of these two polymorphisms. Wild-type TT subjects of FTO rs17817449 lost more weight over the first two months (p=0.0398). An improvement in dietary restraint (avoidance of fattening food) (p=0.0238), disinhibition (p=0.0331), emotional (p=0.0017) and habitual (p=0.0150) disinhibition was associated with a more pronounced weight loss over six months in wild-type TT subjects of FTO rs1421085. Improved GHQ and BDI was associated with a more pronounced weight loss in mutant Thr54Thr subject of FABP2 (p=0.0261) and wild-type CC subjects of GNB3 (p=0.0291), respectively. Conclusion: Genetic screening should only be considered if it is evidence based and has clinical utility. Integration of the results with existing evidence indicates that ADRB2 Arg16Gly polymorphism may be included in a genetic screen for weight loss. The novel findings need to be confirmed in further research.