Common single nucleotide polymorphisms of the fat mass and obesity associated (FTO) gene and their association with obesity and lifestyle factors: a systematic review

Several studies conducted in the entire human genome have shown that the FTO (Fat mass and Obesity associated) gene is most associated with obesity. FTO gene is highly poly morph and several polymorphisms of this gene are associated with obesity. The aim of the present study was to systematically review the gene polymorphism associated with obesity and the role of nutrition and lifestyle. Papers used in this study were collected by searching the Medline, EMBASE, CINAHL, ProQuest, pubmed and Scopus databases and thesis and journals. Key words used for the search were: Gene Polymorphism, obesity, FTO, Fat mass and Obesity associated, diet, physical activity. Studies were limited to human studies in English and Persian languag. All articles between year 2000 and 2012 meeting the inclusion criteria were enrolled in the study. 28 articles were found in the systematic search of databases, of which 18 articles were selected after removal of duplicate articles and papers related to our criteria. The relationship between energy expenditure and energy intake with the FTO gene variants were contradictory. In most studies, high dietary fat intake and obesity risk alleles were significantly associated with the frequency. In most studies, the minor allele was significantly associated with overweight and obesity gene variants in subjects with low physical activity. This study showed that the relation between risk allele associated and overweight and obesity are strongly influenced by lifestyle (energy intake, physical activity and dietary pattern) factors. So modifing the lifestyle pattern may have a preventive role in obesity gene expression in vulnerable people.