Is Childhood Obesity Driven By Genetic Differences in Appetite?

sharma-obesity-dna_molecule9Genetics plays a big part in the development of childhood (and, for that matter, adult) obesity – some folks are simply more genetically prone to weigh gain than others.

Now a study by Silje Steinbeckk and colleagues from Norway, published in JAMA Pediatrics, suggests that while genetic factors are important, these may not act through an effect on appetite or eating behaviour.

The longitudinal study was conducted in a representative birth cohort at the Trondheim Early Secure Study, enrolled at age 4 years during 2007 to 2008, with follow-ups at ages 6 and 8 years. Analyses included 652 children with genotype, adiposity, and appetite data.

While there was clear effect of genetic risk (measured as a composite score of 32 genetic variants) on increase in body weight and fat mass), there was no clear relationship to appetite traits measured at age 6 years with the Children’s Eating Behavior Questionnaire.

Thus, the authors conclude that while genetic risk for obesity is associated with accelerated childhood weight gain, appetite traits may not be the most promising target for preventing excessive weight gain.

So if not through appetite, how do these genes increase the risk for weight gain. Obviously there are a number of possibilities ranging from subtle effects on energy metabolism, adipocyte differentiation or other factors that may not directly be related to eating behaviour.

Another possibility may well be that the instrument used to assess appetite traits may simply not be sensitive and reliable enough to capture subtle changes in ingestive behaviour.

Thus, while there is no doubt that genetic risk may well be a key determinant of childhood obesity, exactly how this effect is mediated remains unclear.

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