Study: Strong genetic component to childhood obesity

So how might a progressive like Mayor Bloomberg try to regulate the genetic component? (Hint: The answer starts with an “E”).

The media release is below.

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Study finds strong genetic component to childhood obesity

Childhood body weight is strongly influenced by genes according to new research published today in the International Journal of Obesity

Previous research has shown that obesity runs in families, and twin studies suggest that this is largely due to genetic factors, with heritability estimates over 50%. 32 genes have been identified as risk factors for obesity but previous analyses suggest that these genes alone cannot fully explain the high level of heritability in childhood obesity, as together they explain only 2% of individual differences in childhood body weight. This has led to a problem of ‘missing heritability’.

In this study, researchers used a new method called Genome-wide Complex Trait Analysis (GCTA), to investigate the molecular genetic heritability of body weight in children. GCTA takes advantage of the fact that some people are more genetically similar to one another than others, by chance; and looks to see whether individuals who just happen to be more genetically similar might also be more similar in weight. Using this approach, GCTA estimates the combined effects of all known common genes across the whole genome, associated with childhood body weight.

The study is based on data from a population-based cohort of 2,269 children aged between eight and eleven years old. Researchers looked at whether children who happen to be more genetically similar might also be more similar in body weight. Using the GCTA method, the researchers found that additive effects of multiple genes across the whole genome accounted for 30% of individual difference in childhood body weight.

Clare Llewellyn from UCL Health Behaviour Research Centre and lead author of the study, said: “These findings are important because they confirm that in children genes play a very important role in determining body weight. At present only a few genetic variants have been discovered, and these explain a very small amount of individual differences in body weight (~2%). These findings suggest there are hundreds of other genetic variants influencing body weight that are yet to be discovered”.

This study underlines the importance of genetic effects in childhood obesity, supporting the current thinking that children of obese parents are most at risk of becoming obese.

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8 responses to “Study: Strong genetic component to childhood obesity

  1. It seems likely, then, that body mass and body fat are driven largely by complex gene factors. That would make sense; if different body mass indices have differing survival traits and different body fat compositions do also, then different stressors would select for more than one set of traits or at least would not select out only a couple of sets of traits.
    Obesity-related health problems tend to contribute to death well after breeding age anyway. Generally speaking, natural selection is going to remove traits that reduce breeding success and obesity is only vaguely such a trait. It may reduce the obese person’s breeding partner pool but nearly everyone gets into the pool at some point.
    As far as eugenics goes — we have quite a mixed social message right now. We’re supposed to be appalled at obesity but we’re supposed to accept all God’s children as they are. Can you say “cognitive dissonance”?

  2. “32 genes have been identified as risk factors for obesity”

    Eating too much has been identified in 100% of cases of obesity.

  3. Which would explain why obesity was hardly know when I was a kid in the Fifties, I guess…. we grew a new gene since then, apparently. Anything to avoid the noxious concept of “personal responsibility”, it would seem.

  4. Snorbert Zangox

    I think that a study that explains 30% of individual weight differences is good reinforcement for a concept that is intuitive, but is still a long way from a proof.

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