Association of Fat Mass and Obesity-Associated (FTO) Gene Polymorphism with Obesity Risk: A Systematic Review Protocol

Introduction: Obesity is a multifactorial condition with a global increase, associated with several chronic comorbidities. The FTO gene is one of the main genetic markers related to obesity risk, especially through the polymorphisms rs9939609 and rs8050136, which influence eating behavior and energy metabolism. Objective: To evaluate the association between FTO gene polymorphisms and the risk of obesity as a predictive marker in adults. Theoretical Framework: Obesity results from the interaction between genetic and environmental factors. The FTO gene, identified in genome-wide association studies (GWAS), has a strong relationship with appetite regulation, energy metabolism, and BMI increase. Its protein acts as a demethylase in epigenetic processes and is expressed in the hypothalamus, being associated with metabolic disorders. Method: Systematic review with meta-analysis, following PRISMA-P criteria and registered in PROSPERO. Searches were conducted in SciELO, LILACS, PubMed, ScienceDirect, and Scopus databases, using DeCS and MeSH descriptors. Study selection was performed by two independent reviewers, and methodological quality was assessed using the Joanna Briggs Institute tool. Statistical analysis will be conducted with BioEstat 5.3, including heterogeneity tests, fixed- and random-effects models, and the Kappa index. Results and Discussion: It is expected to gather consistent evidence on the association between FTO polymorphisms and obesity, considering variations by region, sex, and age, and to contribute to personalized strategies for obesity prevention and control. Research Implications: The findings may contribute to personalized medicine by identifying the FTO gene as a predictive marker of obesity, enabling more effective preventive and therapeutic strategies, in addition to guiding public policies for groups at higher genetic risk. Originality/Value: This study stands out for synthesizing genetic evidence on the FTO gene and obesity through a rigorous systematic review. Its results may guide personalized medicine practices and public policies focused on obesity prevention and control.