Vigorous Exercise Aids Those With Obesity-Related Gene (HealthDay)

MONDAY, Sept. 8 (HealthDay News) -- Physical activity may reducethe risk of obesity in people with a genetic mutation that predisposesthem to high body-mass index (BMI), says a U.S. study.

Recent research has shown a link between BMI and variants of the fatmass and obesity associated with the (FTO) gene. The mutations connectedwith obesity occur in about 30 percent of European populations and areassociated with a 1.75-kilogram (3.9-lb.) increase in body weight,according to background information in the study.

While lifestyle factors such as diet and exercise are important factorsin weight control, it's not exactly clear how they interact withgenetics.

In this study, researchers analyzed DNA samples from 704 healthy Amishadults, average age 43.6, and also conducted a series of physiologicaltests on the participants, including recording their physical activityover a seven-day period.

Among the participants, 54 percent of men and 63.7 percent of womenwere overweight, and 10.1 percent of men and 30.5 percent of women wereobese. The genetic analysis showed that 26 single-nucleotide polymorphisms(SNPs -- changes in a single base letter of DNA) in the FTO gene wereassociated with BMI.

Further investigation found that the two strongest SNPs were associatedwith BMI only in people with low physical activity scores. The SNPs had noeffect on people with above-average physical activity scores.

The study was published in the Sept. 8 issue of the Archives ofInternal Medicine.

"Activity levels in the 'high-activity' stratum were approximately 900calories [860 calories for women and 980 calories for men] higher than inthe 'low-activity' stratum, which, depending on body size, corresponds toabout three to four hours of moderately intensive physical activity, suchas brisk walking, housecleaning or gardening," the researchers wrote.

"In conclusion, we have replicated the associations of common SNPs inthe FTO gene with increased BMI and risk to obesity in the Old OrderAmish. Furthermore, we provide quantitative data to show that the weightincrease resulting from the presence of these SNPs is much smaller and notstatistically significant in subjects who are very physically active. Thisfinding offers some clues to the mechanism by which FTO influences changesin BMI and may have important implications in targeting personalizedlifestyle recommendations to prevent obesity in genetically susceptibleindividuals."

More information

The U.S. National Heart, Lung, and Blood Institute has more about .