Waist size found to be strongly associated with risk of death

Previously on this site I have drawn attention to the fact that the body mass index (weight in kg divided by the square of someone’s height in metres) is not a particularly good gauge of health status. For a start, the BMI tells us noting about the body’s composition, and it is entirely possible for individuals who are quite muscular, for instance, to be labelled as ‘overweight’ or even ‘obese’ despite the fact that they’re not carry much in the way of fat. Also, there is the other matter that studies have found that individuals labelled ‘overweight’ (BMIs of 25-29.9) appear to enjoy at least as good health, if not better, than those with BMIs traditionally labelled as ‘healthy’ (18.5-24.9).

Another major deficiency of the BMI is that it tells us nothing about how any excess fat might be distributed in the body. This is important because it’s well known that fat that congregates around the midriff (abdominal fat) is quite strongly associated with conditions such as heart disease and type 2 diabetes, while weight that accumulates below the waist (gluteofemoral fat) is not. Waist circumference (WC) and the waist-to-hip ratio (WHR) have therefore been offered up as more useful measures with regard to general health and disease risk.

Last week saw the publication of a study which assessed the relationship between BMI, WHR and WC and overall risk of death in almost 360,000 adults across 10 European countries. Individuals in this study were followed for an average of almost 10 years. When assessing the relationship between the various measures and mortality, researchers took into account other so-called confounding factors such as smoking, alcohol consumption and activity.

The relationship between BMI and overall risk of mortality revealed J-shaped curves, means that both low and high BMI is associated with an increased risk of death. What was most interesting is where the low-point in the curve (the BMI at which mortality was lowest) came. For women, this was a BMI of 24.3 (very much at the upper end of the ‘healthy’ range). For men, on the other hand, the lowest risk is in men with a BMI of 25.3 (in other words, men who would traditionally be labelled as ‘overweight’ have the lowest risk of death).

Using a BMI of 23.5 – < 25.0 as a reference point, the researchers assessed risk of death in individuals with BMIs higher and lower than this. In men, individuals with a BMI of 25.0 - < 26.5 were at a 9 per cent reduced risk of death. Risk of death only became clearly statistically significantly increased once the BMI was over 30. In women, clearly enhanced risk of death was only seen those with BMIs over 30 too. This evidence, like quite a lot that has gone before, does call into question the wisdom of telling individuals who are 'overweight' that they should lose weight. The researchers went on to assess the relationship between WHR and WC and risk of death. Here, the impact of a person's BMI was also taken into consideration. Here, there was found to be strong relationships between both WHR and WC, and risk of death. Men with the highest WCs had a more than 2-fold increased risk of death compared to those with the lowest waist measurements. In women, higher WC was associated with a 78 per cent increased risk of death. Also, the highest WHRs were associated with a 68 and 51 per cent increased risk of death in men and women respectively. What this all boils down to is that, yet again, the BMI has been found wanting as a marker for health, and again the validity of the appropriate of the traditional bands of 'healthy' and 'overweight' has been called into question. And again we see that assessment of the extent of fatty accumulation around the middle is a potentially valuable tool in assessing health status. Those keen to maintain a 'healthy' weight might do well to focus far less on their actual weight or BMI, and more on their size of their belly. In this study, the 20 per cent of men and women with lowest risk of death had waist sizes measuring less than 86 cm (34 inches) and 70 cm (25.5 inches) respectively. References:

Pischon T, et al. General and abdominal adiposity and risk of death in Europe. NEJM. 2008;358(20):2105-2120

8 Responses to Waist size found to be strongly associated with risk of death

  1. Thras 20 November 2008 at 1:25 am #

    Is the ideal waist size about what we’d expect it to be? Or like BMI, is it a little higher than was previously thought?

  2. Anna 20 November 2008 at 1:51 am #

    Men with big bellies often have a warped sense of their belly size anyway, as they just buckle their belt lower and lower, below their “wheat belly”.

  3. Criquette 21 November 2008 at 2:31 pm #

    Very few people these days have that previously coveted hour glass figure mentioned with a waist size for women @ 25.5 inches.
    What is the recommended waist size as everyone can’t have the same measurement. As ever statistics are just that.

  4. Florence 21 November 2008 at 3:38 pm #

    I’m doomed! I’ve not had a waist size 25.5 since I was 15 and I can’t see it ever returning to that at 56.

  5. Catherine 22 November 2008 at 7:40 am #

    Looking at the circumference of 70 cm for women I see the size of a child’s waist, 70 cm for an adult seems rather anorexic. A GP/Homeopath in Cape Town, Dr David Nye recommends ‘the waist be measured at the navel with the tummy pulled in. In males it should be less than 102 cm (ideally less than 94 cm), and in females it should be less than 89 cm (ideally less than 80 cm)’. This seems more realistic to me.

  6. Richard 22 November 2008 at 4:05 pm #

    The average body shape of women has changed in the last 100 years, but food is more plentiful and we eat more protein.

    But also the average Briton eats much more carbohydrate, which can lead to a rise in the production of androgens. I wonder if this can effect body development and lead to a more androgynous body shape seen in today’s women?

  7. Becky 25 November 2008 at 9:30 pm #

    I would have thought that the key meaurement would be the waist to hip ratio rather than the straight waist measurement. May we please have some indication as to what this is? e.g. the waist should be 60% of the hips, something like that? Having the ratio would mean that the waist size was in tune with the person’s build but it’s not mentioned in Dr Briffa’s article. More information, please.

  8. debi 29 November 2008 at 1:16 am #

    Does these waist measurements for women include menopausal/postmenopausal women who are not on hormones, do not have the time to be in a doctor’s office weekly like Suzanne Sommers to be tested for hormone levels? I used to have a great shape but that was before menopause like most women. Still not overweight but can’t get rid of the new belly? How does this study fit in with menopause?

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