This study was a cross-sectional study was carried out from September 2016 to October 2017 on 199 randomly selected participants referred to the Shohadaye Valfajr health center, Shiraz, Iran. In brief, participants were overweight adults with BMI between 24/9 to 29/9 kg/m2 and aged 20 to 45 years. The Inclusion criteria was defined as willingness to participate in the study, not participating in a weight management programs during two past months and no recent weight loss greater than 5%. We excluded participants with alcohol or drugs addiction (n=1), smoking, certain weight-related diseases (including specific psychological or neurological disorders, insulin resistance, thyroid disease, liver disease, renal failure, infectious and other specific diseases) (n=1), and pregnant or lactating women (n=1). All participants signed a consent form before participation in the study.
Anthropometric Measures
The height of the participants was measured with a calibrated tape line fastened to a wall and without shoes with a precision of 0.5 cm. A bio impedance analysis scale (BIA) (Tanita, Japan/BC-418) was used to measure anthropometric indices such as body weight, Body Mass Index (BMI), skeletal muscle percentage (SM%), body fat (BF), skeletal muscle (SM) and body fat percentage (BF%) after entering their height, age and gender.
Genotyping:
DNA was extracted from whole peripheral blood sample using the DNA extraction kit (SinaPure DNA Kit, PR881612/EX6001/CinnaGen/Iran). DNA samples were stored at −20 °C before genotyping. After DNA extraction, the concentration of the extract material was obtained by spectrophotometer NanoDrop device (ND1000,USA). FTO gene was genotyped for rs9939609 polymorphism via tetra primer amplification refractory mutation system polymerase chain reaction(ARMS-PCR)
Macronutrients’ intake
Usual Macronutrients’ intakes of participants were assessed by a validated 168-item semi-quantitative FFQ (16). The FFQ consisted of 168 food items with standard portion sizes commonly consumed by Iranian people. Face-to-face interviews were administered by a trained dietitian.
Macronutrients’ consumption frequencies were converted to grams per day by using household measures. Daily intakes of energy were also measured for each person by using the modified US Department of Agriculture food consumption database, which was modified for Iranian foods.
Laboratory Measurement
Serum TG, TC, HDL, LDL, glucose and insulin levels were measured after 12 hours of an overnight fasting. leptin and adiponectin serum were measured using EDTA-anticoagulated tubes. Insulin, leptin and adiponectin level was determined by ELISA test (LDN, Germany).
Statistical Analysis
ANOVA test was used to compare anthropometric indices, plasma levels of hormones and lipid and sugar profile between different FTO genotypes. Tukey test was used for comparison the calorie and macronutrient intake between three genotypes. To adjust the effects of confounders, linear regression was used after that the assumptions of the linear regression model were confirmed. Statistical analyses were performed using SPSS version 23.0 (IBM SPSS Statistics for Windows, IBM Corp., Armonk, NY, USA). The results were considered statistically significant at P<0.05.
Ethics approval and consent to participate
This study has been approved by Local ethics review boards at Shiraz University of medical sciences (Code: ir.sums.rec.1395.100).