Not All Obese People Die From Fatness. Well, Duh

Most of us know how inaccurate the BMI is as a measure of fat & health. A 16-year prospective study just released shows that obesity alone does not determine mortality down the road.The study followed 29,533 volunteers from the Cooper Clinic in Dallas over an average of 16.2 years; 6,224 were considered obese; the obese folks were categorized into a 4 point classification system based on fatness-related illnesses – Edmonton Obesity Staging System (EOSS) levels 0-3.

One of the things I did in my former life was to critique scientific articles. I won’t do that in detail here but will point out a few limitations and summarize. Plus, I encourage you to read the results in the abstract plus look at Table 1 to see the EOSS classification system of health that they used rather than BMI and Table 2 to see the characteristics of the participants.

Bottom line: the more obesity-related diseases at the start (for example, diabetes, heart disease, hypertension, sleep apnea, limitations in daily activities, even mental health issues), the higher risk of mortality over follow-up in  EOSS groups 2 & 3. Those in the EOSS classes 0 or 1 actually had lower risk for heart deaths. All EOSS categories had higher risk of cancer. (See Figure 1 from the article below for a picture of risk of death at the end of the study.)

The participants were highly educated, White men (sigh), which means this is not representative of most of us. Not all participants were available for follow-up over the entire study, and the length of time the participants were followed varied by group. (For example the normal weight people were followed for an average of 17.6 years, EOSS 0 and 1 for 18.4, EOSS 2 10.2, and EOSS 3 11.9) I don’t see that the authors attempted to account for this statistically. (But I didn’t read it that closely in my attempt to get this on the blog quickly.) Weight or fat measure was not analyzed over time, so fluctuations could have occurred differentially among the groups.

This doesn’t mean stay fat. This lends credence to the saying, “fat and fit” (If you are a wealthy, educated White male living in Texas…) But the cancer risk is hard to ignore. More importantly it provides a measure for other studies to use rather than BMI for measuring risk in fat folks. Also, if I were a practicing doc, I would start incorporating this scale to assess risk and advise patients. (Because BMI sucks so badly.)

A final caveat. Although this study shows increased risk of death among those with more fat-related (my words) conditions, it does not prove that treatment of fatness or the related conditions will decrease the risk of dying or dying from cancer or heart disease. This study does not address that question. But it is always tempting to extrapolate…

HR=hazard ratio. How much more at risk than the normal weight group. NW=normal weight. CVD=cardiovascular disease

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9 thoughts on “Not All Obese People Die From Fatness. Well, Duh

  1. Is it wrong that I don`t pay attention to BMI – I find I work out regularly, not thin by any stretch of the imagination, but I do have muscle. I find it frustrating that I`m always teetering on the edge…That`s why I stopped paying attention to it.

  2. Muscle mass is part of the reason BMI is so bad – muscle weighs more than fat, so you can be very muscular and have a higher BMI and not be “fat”. Another example, as women age, their height shrinks, BMI ignores that. BMI is an oversimplified measure of fat and certainly not a measure of health risk. I always said to look in the mirror to assess fatness (unless one has a distorted body image).

  3. Pingback: Obese | -Not All Obese People Die From Fatness. Well, Duh- «

  4. I’m terrible with charts and studies and science-y stuff, so I just *try* to focus on choosing good actions and leave the rest of it to someone else to worry about. It irks me, though, that the insurance people use BMI as one of the factors in determining coverage rates.

    • Insurance companies will find the easiest, least scientific method that guarantees the biggest exclusion of coverage – never fear about their consistency!

  5. Last summer, when I was at my lowest weight in over 20 years, I was still overweight according to the BMI charts – but I fit into size 6 clothes, was running, and working out three times a week with a trainer. Yep – I may have weighed a lot for that chart, but it was muscle, and nice-looking muscle at that! (come back to meeee, muscle!)

    I reject the BMI charts, btw. 😉

  6. Those damned BMI charts cost me a fortune in insurance premiums back in my much slimmer days when I actually had life insurance! I am muscular and have always weighed much more than I appear. I also have very few risk factors am have been considered obese for 20 years. I sort of disagree on the sleep apnea as being due to weight, though. My skinny sister , skinnier brother and only moderately overweight dad have it, too. It just runs in our family.

    • Just like diabetes, hypertension and heart disease can occur in thin people, so can sleep apnea. Those are just more frequently seen with obesity and have some causal association because it has been shown that losing fat does decrease blood pressure, improve blood glucose control, etc. But like the study shows, many fat folks can have zippo problems and live as long as thin people.

  7. I think plenty of studies have supported the BMI as a predictor of future health problems. The higher the BMI over normal the greater the likelihood for problems. I find the range of allowable weight for the normal range to be fine. Perhaps because I have a normal BMI I am biased. People have gotten too heavy. Don’t worry, soon the increased disease states will be considered normal.

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