Study: Genetics Have Little Effect on Response to Weight Loss Interventions in Children
Genetic susceptibility toward obesity has little impact on whether lifestyle interventions aimed at weight loss are successful in children who are overweight or obese, a new study suggests.
The study, “Obesity Genes and Weight Loss During Lifestyle Intervention in Children With Obesity,” was published in the journal JAMA Pediatrics.
Body weight is regulated by a variety of factors, including genetics and lifestyle (diet, exercise, etc.). Lifestyle interventions — such as exercising more often or eating fewer calories — can reduce body fat; however, such interventions tend to yield inconsistent results. Whether people with certain obesity-associated genetic variations might be more or less likely to respond to lifestyle interventions targeting weight loss has not been clear.
The Long-term Effects of Lifestyle Intervention in Obesity and Genetic Influence in Children (LOGIC) study was conducted from 2006 to 2013. It enrolled children ages 6 to 19 who were referred to a German rehabilitation center for inpatient weight-loss treatment. The treatment, given over four to six weeks, focused on behavioral changes, increased physical activity, and a calorie-restricted diet.
Genetic information was available for 1,198 children who participated in LOGIC. Their mean age was 14 and 56% were girls.
Over the course of the intervention, mean body weight decreased by 8.7 kg (about 19.2 lbs). Likewise, mean body mass index (BMI) — a ratio of weight to height — decreased by 3.3 kg per square meter.
Using statistical analyses, the researchers looked for associations between losing weight over the course of the program and 56 genetic variations that have been linked with high obesity risk.
Of the 56 analyzed variants, only five were associated significantly with intervention outcomes. Individuals with the variants rs12940622 and rs7164727 had less weight loss, whereas those with the variants rs13201877, rs10733682, and rs2836754 had more reduction in weight.
Yet, even though the effect on weight loss was statistically significant — that is, mathematically unlikely to be the result of random chance — the size of the effect was small, generally only a fraction of a kilogram.
“Our study offers evidence showing that genes susceptible to obesity play a minor role in treatment success in children who are overweight or obese … This study suggests that environmental, social, and behavioral factors play the most important role in obesity treatment strategies in children, whereas genetics are secondary,” the researchers concluded.
Marie-France Hivert, MD, and Ann Chen Wu, MD, professors at Harvard Medical School, wrote in an accompanying editorial: “One reassuring lesson from this study and many others is to remind patients, ‘you are not doomed by your genes.’ Lifestyle interventions can work and maybe work even better in individuals with a genetically higher risk for overweight or obesity,”
Hivert and Wu also said this study has several limitations. For one, the intervention was given to children who were staying in the hospital. While this setting was helpful for standardizing the intervention, it also limits generalizing the results, since weight-loss programs are typically conducted outside of a hospital setting.
The study also assessed only 56 obesity-related genetic variants; however, hundreds of genetic variations have been linked to BMI in various studies.
The editorialists added that the focus on BMI-linked genes may mean missing other genetic variants that, while not linked to obesity risk itself, could affect how a person responds to lifestyle interventions.
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