The association between FTO rs9939609 gene polymorphism and anthropometric indices in adults

Fat mass and obesity-associated gene (FTO) is the most studied obesity-related gene up to date. We aimed to assess anthropometric indices in carriers of FTO rs9939609 polymorphism with overweight across Iranian population (Shiraz) to find out the associations of this polymorphism with obesity indices.

This was a cross-sectional study conducted on 198 overweight healthy adults aged 20-45 years old. We assessed the body composition of the participants using bioelectrical impedance analyzer. In addition, we measured the waist circumference (WC) and hip circumference (HC). Waist to hip ratio (WHR) and waist to height ratio (WHtR) were also calculated by equations. The participants' genotype was determined by ARMS-PCR. Also, data analysis was performed using SPSS software version 20 and R software version 3.6.2.

The mean values of body mass index (BMI) and age of the participants were 26.93 ± 1.13 kg/m² and 33.33 ± 6.35 years old, respectively. Homozygous carriers of A-allele had significantly higher values for BMI (0.60 kg/m², p = 0.026), WHR (0.04 unit, p = 0.003), and WHtR (0.02 unit, p = 0.030) than the homozygous carriers of T-allele. Individuals with AA genotype had greater WC (2.66 cm, p = 0.042, and 4.03 cm, p = 0.002), fat mass (2.24 kg, p = 0.004, and 3.02 kg, p = 0.001), and trunk fat (1.53 kg, p = 0.001, and 2.08 kg, p = 0.001) compared to those with AT and TT genotypes, respectively. Interestingly, after adjustment of the confounders, significant associations were observed among rs9939609 polymorphism and BMI, Wt, WC, trunk fat percentage, WHR, and WHtR.

A-allele of the FTO rs9939609 polymorphism was indicated to be associated with greater general and central obesity in adult population of Shiraz, Iran.