Friday, December 26, 2014

Obesity and heart disease: mixed messages

Here’s another good reason to be very leery about second-hand reports about scientific study results.

Finally, it seems, new reports found some good news about being obese and having heart disease—or did they?

The studies suggest that people who suffer heart failure and who are obese are more likely to be alive a year later than thin folks are. Researchers call it the “obesity paradox.” Here’s one of those studies, in the December 2013 Journal of the American College of Cardiology.

Kinda seems like good news to those of us carrying a few extra pounds.

But almost every news medium and even Elsevier, a publisher of scientific papers, got this story wrong—suggesting that fat was protective against heart disease: “Is being overweight sometimes a good thing? Data suggest higher BMI protects against adverse cardiovascular outcomes, reports Mayo Clinic Proceedings.”

And that, of course, is wrong, wrong, dangerously wrong.

Here’s what the papers really say: If you already have heart disease, then you’re less likely to die soon if you’re too fat than if you’re too skinny.

The first study listed above says it clearly enough: “Although obesity is an independent risk factor for heart failure (HF), once HF is established, obesity is associated with lower mortality.”

The suggestion that obesity protects against heart disease “is potentially a dangerous message to promulgate from retrospective data in an environment saturated with an obesity epidemic and obesity-related conditions such as type 2 diabetes mellitus and coronary heart disease,” say these researchers in a Mayo Clinic journal

And the authors of still another paper say: “In our large, community-based sample, increased body-mass index was associated with an increased risk of heart failure. Given the high prevalence of obesity in the United States, strategies to promote optimal body weight may reduce the population burden of heart failure.” 

Being fat makes you twice as likely to get heart disease as people of healthy weight. But once you’re real sick, the fat folks with heart disease are 22-27 percent less likely to die in the short term. The obesity paradox discussion in popular media generally only looks at the second half of that equation.

It’s a little like cell phone company XXX saying, “If you’ll pay double for this $500 phone, I’ll give you $250 back and it’ll only cost you $750.” And then all the media saying you ought to choose cell company XXX because of the great rebate, not mentioning that you’re paying a 50 percent premium.

The American Heart Association notes that: “Obesity increases the risk for heart disease and stroke.” 
 And not only that, “but it harms more than just the heart and blood vessel system. It's also a major cause of gallstones, osteoarthritis and respiratory problems.”

A 2013 study confirms this: “Epidemiological studies have recently shown that obesity, and abdominal obesity in particular, is an independent risk factor for the development of heart failure.” 

The key statistics: nearly 70 percent of people with heart disease are obese, and, from this study by the Massachusetts Medical Society, “As compared with subjects with a normal body-mass index, obese subjects had a doubling of the risk of heart failure.”

And the bigger you get, the higher the risk: “A graded increase in the risk of heart failure was observed across categories of body-mass index.”

Why is this important for Hawai`i? The state’s obesity rate climbed from under 10 percent in 1990 to more than 20 percent now. 

While we have nearly the lowest obesity rate in the nation (21.8 percent, with only Colorado lower at 21.3), consider this: In 1991, no state in the U.S. had an obesity rate above 20 percent. Now they all do.

And while our rate in the Islands is comparatively low, it’s still dangerously high—in 2013 26.8 percent for men and 20.3 for women. In 2010, there were more than 78,000 people in the Islands with heart disease.

Sending mixed messages about the dangers of obesity is a danger in itself.

© Jan TenBruggencate 2014

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