Physical activity may cancel out the effects of the “obesity gene” in adolescents, as it has been shown to do in adults.
“To our knowledge, our study is the first to report an interaction between the FTO rs9939609 polymorphism and physical activity level on adiposity indices using objectively assessed physical activity in adolescents,” said Jonatan R. Ruiz, Ph.D. of the Karolinska Institute, Huddinge, Swedenoand his associates.
The investigators genotyped and assessed body mass index, waist circumference, and body fat percentage in 752 adolescents participating in the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS) They also assessed subjects' physical activity level using an accelerometer attached to the lower back rather than by using subjective measures such as questionnaires.
As expected, the fat mass- and obesity-associated (FTO) gene variant known as rs9939609 was significantly associated with higher BMI, greater waist circumference, and higher percentage of body fat.
However, there was no such association in the subgroup of carriers who participated in at least 60 minutes per day of moderate to vigorous physical activity, Dr. Ruiz and his colleagues said (Arch. Pediatr. Adolesc. Med. 2010;164:328–33).
The U.S. Department of Health and Human Services recommended this level of activity in recently released guidelines. Therefore, the study findings “have important public health implications and indicate that meeting the physical activity recommendations may offset the genetic predisposition to obesity associated with the FTO polymorphism in adolescents,” the researchers added.
This study was supported by several European government organizations. No financial conflicts of interest were reported.