Glareh Koochakpour - Maragheh University of Medical Sciences, Maragheh, Iran
Zohre Esfandiar - Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Firoozeh Hosseini-Esfahani - Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Parvin Mirmiran - Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Background and Aim: The results of studies on the effect of trans-fatty acids (TFAs) and added sugars on obesity incidence are not consistent. This study aimed to investigate whether the association of changes in general and central obesity with added sugar and TFA intakes; is modified by common fat mass and obesity associated gene (FTO) polymorphisms, in isolation or in a combined-form genetic risk score (GRS).Methods: Subjects of this cohort study were selected from among adult participants of the Tehran Lipid and Glucose Study (n=4292, 43.2% male). Dietary data were collected using a valid and reliable food frequency questionnaire. The genotypes of selected polymorphisms (rs1421085, rs1121980, rs17817449, rs8050136, rs9939973, and rs3751812), were determined. Genetic risk score (GRS) was calculated using the weighted method.Results: The mean age of participants was 42.6±14 and 40.4±13 years, in men and women respectively. There was a significant interaction between the FTO rs9939973, rs8050136 and rs1781799 polymorphisms and TFAs, regarding body mass index (BMI) change. Changes in waist circumference (WC) and BMI were significant only among the FTO rs1781799 risk allele carriers, across quartiles of added sugar intake (Ptrend=0.03). There was a significant interaction between the GRS and TFAs intake, regarding changes in WC (Pi=0.04); a higher intake of TFAs was associated with higher changes in WC in subjects with high GRS, compared to individuals with low GRS. Conclusion: Our findings suggest that TFA and added sugar intakes could increase the association between genetic susceptibility of FTO SNPs and BMI or WC change.

trans-fatty acids, added sugar, FTO polymorphisms, Obesity, interaction