A variant in the FTO gene is associated with increased body mass index (BMI) and with both more premeditation and more perseverance in the personalities of young American adults of European ancestry, a study suggests.
This indicates that impulsive behavior is associated with higher BMI and obesity, the scientists said.
The study “Association between impulsivity traits and body mass index at the observational and genetic epidemiology level” was published in journal Scientific Reports.
Previous research suggested that behaviors such as high neuroticism — tendency toward negative feelings, including anxiety, depression, or self-doubt — and lack of self-discipline increase the risk for obesity.
Impulsivity — the tendency to act without considering consequences — also has been linked to obesity. In fact, evidence suggests that both impulsivity and obesity traits are explained, in part, by genetic inheritance.
Researchers in Canada and the U.S. investigated the relation between BMI, genetic variations, and impulsivity.
The study included 998 participants (mean age 21.7 years, range 18–30) of European ancestry. They were either students or staff members from the University of Chicago or University of Georgia. Their mean BMI was 24.1 kg/m2, 21.7% of the participants were overweight (BMI values between 25 and 29.9) and 9.9% were obese (BMI of 30 or greater).
The team evaluated three domains of impulsivity — impulsive choice, action and personality — comprising a total of 14 behavior traits.
Results showed that four impulsivity parameters across the three domains correlated with higher BMI. Examples included negative urgency, or the tendency to act rashly when distressed, and the Conners continuous performance test of attention.
Genetic analysis revealed that a single nucletotide polymorphism (SNP) — a change in a single nucleotide, the building blocks of DNA — in the fat mass and obesity-associated (FTO) gene was associated with greater BMI. This variant, known as rs3751812, also was linked to both more premeditation and more perseverance.
The association between the FTO variant and higher BMI remained significant after adjusting for lack of premeditation, but not after accounting for lack of perseverance or for both traits. The researchers used this scale to assess those behaviors.
“These results suggest that the association between FTO and BMI may involve changes in impulsive behaviors,” the researchers wrote.
Overall, “our observational and genetic data indicate a complex pattern of association between impulsive behaviors and BMI in healthy young American-European adults” they said.
“More research is needed to precise the contribution of SNPs in FTO and other obesity genes to impulsive behaviors in diverse ethnicities” they said.