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Birth Year & Obesity

January 15, 2015

Scientists find that the most well-known genetic marker for human obesity had no effect before the 1940s.



Does your birth year affect your weight? I’m Bob Hirshon and this is Science Update.

People with one variant of a gene called FTO are much more likely to be obese than people carrying the other variant. But that’s only true for people born after 1942.  In the Proceedings of the National Academy of Sciences, Harvard researcher Niels Rosenquist and his colleagues report that for people born earlier, the gene variant had no effect.

NEILS ROSENQUIST (Harvard Medical School):

Meaning, that just within the same family, you could be born in the same environment, with very similar genes, and because you happen to be born a couple years later than your older sibling, if you had that risk variant on average, you were more likely to become obese.


The researchers are now looking into what changed in the 1940s that might be responsible for the difference. Rosenquist says the work highlights the fact that when it comes to risk, genetics is just one piece of a complex puzzle. I’m Bob Hirshon, for AAAS, the science society.