Even obesity paradoxes can't "excuse" fatness

Junkfood Science's latest instalment in its series on the obesity paradox, that is, the disconnect between what we believe about being overweight and what the actual scientific evidence shows.

 

It also manifests itself in the knots researchers tie themselves into when trying to spin their own results so they give the "right message."

 

This study into the links between excess weight and increased risks of mortality was a null study. That means it found no such link. In fact, it found the opposite. So it was fun to see how this "inconvenient message" was spun in the associated press release and the media coverage of it.

Reporting research finding anything positive about fat is accompanied by disclaimers, caveats and every effort to minimize its significance. It’s even called an obesity paradox, perhaps hoping we’ll think it an anomaly, rather than where the strength of the evidence lies. You’ve probably caught the news stories about a Canadian study reportedly showing that people with “a few pounds,” who are “slightly overweight,” are carrying “a little extra weight,” have “excess pounds, but not too many,” and are “overweight but not obese” will “actually live longer than those of normal weight.” But that isn’t what this latest study found. It’s what the press release said it found.

So, what did the study actually find?

The results of this epidemiological study were published in Obesity, the journal of the Obesity Society. This study found that none of the relative risks associated with mortality they examined were tenable [explained here], except for one. Age. At age 65, the relative risks of dying rose to 44.35 times compared to age 25; and by age 75, relative risks are 119-fold. We should stop right there, as tenable correlations are the only ones that deserve our focus. But that wouldn’t have made a news story, so what followed was splitting hairs among the rest.

Looking at corrected BMIs, according to the breakdowns adopted by the world’s governments, the authors found that compared to ‘normal’ BMIs (18.5 up to 25):

 

● being overweight (BMI 25 up to 30) was associated with a 25% lower risk of dying

 

● being obese (BMI 30 up to 35, which includes about 80% of all obese people) was associated with a 12% lower risk of dying.

 

● And the risks associated with the most ‘morbidly obese’ (BMIs 35+) — the uppermost 3% of this Canadian cohort— were statistically the same as those with ‘normal’ BMIs. [RR=1.09 (0.86-1.39, 95% CI) versus RR=1.0.]

 

Go to Junkfood Science to read the full post. Unsurprisingly, (I would have thought), it is age that is the most tenable risk factor it seems!

 

Posted via email from Garth's posterous