A 3-year intervention with a Mediterranean diet modified the association between the rs9939609 gene variant in FTO and body weight changes

Abstract

The aim of this study was to analyze the effects of the rs9939609 (T/A) gene variant in fat mass and obesity-associated gene (FTO) on body weight changes after 3 years and its modification by a randomized nutritional intervention with a Mediterranean-style diet in a population of subjects at high cardiovascular risk. A substudy of PREDIMED, which is a randomized trial aimed at assessing the effect of the Mediterranean diet (MD) for primary cardiovascular disease prevention. There were three nutritional intervention groups: two of them with a Mediterranean-style diet and the third was a control group advised to follow a conventional low-fat diet. A total of 776 high cardiovascular risk subjects aged 55-80 years. Anthropometric measurements were recorded at baseline and at 3 years. The participants were genotyped by RT-PCR, followed by allelic discrimination. Homozygous subjects had the highest baseline body weight. The dominant model showed that subjects carrying the A allele had the lowest body weight gain (B=-0.685; P=0.022) after 3 years of nutritional intervention compared with nonmutated subjects (TT genotype) regardless of the nutritional intervention. Moreover, this effect was statistically significant in carriers of the A allele only among those allocated to the MD groups (B=-0.830; P=0.018), but it was not significant among those allocated to the control group (P for interaction=0.649). This study confirmed the association between body weight and the FTO rs9939609 polymorphism. Interestingly, our results showed that, although at baseline the A allele was associated with higher body weight, after 3 years of nutritional intervention with a Mediterranean-style-diet, A-allele carriers had lower body weight gain than wild type subjects. No interaction between nutritional intervention and the polymorphism was found.