Tuesday, October 9, 2007

Blood pressure and weight predict heart failure

Ramachandran S. Vasan, of Boston University School of Medicine and colleagues studied 3,362 subjects (57 percent women) who attended routine examinations between 1969 and 1994.
The team examined the participants' blood pressure and pulse pressure and BMI measurements. BMI is the ratio of height to weight that is commonly used to determine if someone is over- or under-weight. (Like no one knows what BMI means in this day and age)
These measurements were classified as current; recent (average of all available measurements during the decade); or remote (average of all available measurements obtained 11 to 20 years before the examination).
A total of 518 subjects developed heart failure. The researchers found that recent systolic blood pressure (the higher number in a blood pressure reading), pulse pressure and BMI were all associated with the risk of heart failure. An association was also observed between heart failure and remote systolic blood pressure, pulse pressure and BMI.

518 people out of 3,362 is 15%, over 25 years (and some of the measurements weren't current, some were anywhere from 11 to 20 years old). So, if the measurements in some cases were that old, could they have changed between the time the measurements were taken and those people developed heart failure (if indeed any of them did)? And if the measurements had changed, in what direction had they changed? Did the blood pressure, pulse pressure, and BMI increase, or did they decrease? Did all 3 measurements increase/decrease, or just one or two? What affect did that have on the results? What were the family histories of the people involved in the study? Did hypertension run in their families? Had other family members developed heart failure? Nowhere in this article is any of that covered, and I would say those are all relevant factors that should be taken into consideration.

"The prevention of heart failure should begin early in life, and should include screening for elevated blood pressure and BMI," Vasan told Reuters Health. "Failure to identify or treat such modifiable risk factors in early and mid-adulthood may result in the loss of opportunities to reduce the incidence of heart failure in later life."

Failure to identify or treat such modifiable risk factors? Since when is BMI modifiable? Permanently, I mean? I would think that losing weight, only to gain it back and possibly more, would be worse than not losing it at all, even for those at risk of developing heart failure. Especially since repeated loss and gain of weight usually means muscle mass is lost first (and your heart is a very important muscle), and when weight is regained, it usually isn't muscle that is regained, it's fat. So any muscle you've lost from your heart is not going to be replaced (and wouldn't that lead to heart failure if you have hypertension to begin with?). If I'm wrong, let me know, I want to know if my conclusions are erroneous.

9 comments:

  1. Hi Mariellen,
    I just blogged about your entry on my blog, here: WellRoundedType2. I think your question about whether or not BMI is modifiable is a terrific one. I don't have an answer. I think that when epidemiologists think about risk factors, they aren't necessarily thinking about them as individual but rather population characteristics. But the conclusions that are drawn focus on individual behavior rather than policies that affect populations.

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  2. "The researchers found that recent systolic blood pressure (the higher number in a blood pressure reading), pulse pressure and BMI were all associated with the risk of heart failure."

    What are we supposed to make of this? Is it recent changes that are the issue or 'average' over time?

    If those three factors are associated with heart failure, is that independent of each other, or linked together either 2 or all 3. Either the article is unclear, or I'm just not getting it, analysis of the actual study is required.

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  3. Way to actually read the journal article before you ask a bunch of stupid questions that are thoroughly answered in the paper.

    http://hyper.ahajournals.org/cgi/content/abstract/HYPERTENSIONAHA.107.095380v1?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=vasan+lee&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

    Maybe you should leave science to the scientists and go have yourself another donut.

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  4. Paper

    Read the paper before you criticize the results!

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  5. Why is it always "donuts" with these trolls? I swear they must all whack off to the thought of us stuffing ourselves silly, otherwise why else would they get all red in the face and nasty when we tell them we're NOT stuffing ourselves silly? Like they know exactly what I eat because they're thin and therefore have special powers of divination, and I don't know, couldn't possibly know what I put in my mouth, because I'm a fatass?

    Mariellen's basic question is a fair one. If all it took was a few minor modifications in exercise and diet to make fat people thin -- or "prevent obesity" -- and we knew exactly what these modifications were, why are people getting fatter? Because we're such rebels who just thumb our noses at our doctors and do whatever we want? Not hardly, grasshopper. Some of us get fat doing exactly what our doctors tell us to do.

    And it's completely fair to question whether chronic dieting, which almost every fat person has done from a very young age, could lead to heart muscle wasting. That it's not considered more widely by so-called scientists is, frankly, scandalous.

    So put down that bong and leave the science to people who actually aren't allergic to independent thought, K?

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  6. Meowser-

    YOU didn't read the paper either!

    The paper says that people who used to have a BMI of over 30 and then were under 30 had a greater risk of heart disease than those who stayed over 30. It fucking agrees with you!

    Christ! You people don't even read the things you yell about! You just pick and choose what you think will offend you the most, without considering the rest.

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  7. Maybe Anonymous should notice when people are just asking questions before s/he elevates things to the giddy intellectualism of the 'donut' rationale that is the coup de grace of any discussion involving fat people.

    Asking questions is sign that one's brain is switched on, maybe when yours is warmed up Anon, you can mention burgers or other devastating culinary indictments that reduce us to wreckage.

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  8. I have tried reading studies published in medical journals, and usually, if you don't subscribe to them, you aren't allowed to read the study unless you pay for the article. So, anonymous posters #2 and #3, unless you have a money tree in your yard and are willing to pay for those studies for me so I can read them, you can piss off.
    Anonymous #1, thanks, every bit of information I can learn from others is greatly appreciated.
    Exactly, mumboj, and I didn't have time last night to look for the article and see if it was one I could read for free.
    Thanks, meowser, you said it better than I could. Trolls don't annoy me much, tho, since I just consider the source and either pity them or laugh at them (or both, depending on my mood).

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  9. All right, I read the paper. And I stand by my conclusion that modifying BMI permanently is not do-able. DIETS DON'T WORK FOR PERMANENT WEIGHT LOSS! If they did, there would be no fat people. Also, my question about repeated dieting and loss of muscle mass, with the heart being a muscle, is a valid question that has not been taken into consideration. There is no way that one's body can distinguish between heart muscle and any other muscle in the body, muscle is muscle, no matter where it is located. So, if one diets repeatedly, and keeps restricting calories to keep losing weight, one's body will feed off the muscle, thus weakening itself (and one's heart). I can see where that could lead to heart failure, and THAT is not addressed in this article. Neither does the article mention whether any of the people who developed heart failure were repeat dieters who could have damaged their hearts in this way.

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