Friday, September 24, 2010

Research Update: Waist Circumference And Mortality

Waist Circumference And All Cause Mortality In A Large US Cohort
Jacobs EJ, et al.
Archives of Internal Medicine, 2010 170:1293-1301

Objective: To study the association between waist circumference and mortality in men and women in the Cancer Prevention Study II Nutrition Cohort.

Study Population: 48,500 men and 56,343 women 50 years of age or older from the Cancer Prevention Study II Nutrition Cohort were followed from 1997-2006.  In that time 9,315 men died and 5,332 women died.

Results:  Very high levels of waist circumference were associated with a 2 fold higher risk of mortality in both men and women compared to a normal size waist.  A very large waist size was considered 120 cm or 47.2 inches for men and 110 cm or 43.3 inches in women. 

Waist circumference was associated with an increased mortality in all categories of body mass index in both men and women.  Therefore, no matter what your BMI: normal, overweight or obese, the larger the waist circumference, the higher the risk of death.

Comment:  This study is interesting for a variety of reasons:

#1- It is a very large sample size which increases the power of the study to measure what it intends to.

#2- A doubling of the risk of death in a 10 year period for those with the highest waist circumference is a very significant finding with a huge public health relevance considering that 50% of men and 70% of women between the ages of 50-79 are above the standard for waist circumference. 

#3- Even if your BMI and weight are considered normal, your waist circumference is still highly relevant to risk of death.  Most people who have a normal weight and/or BMI feel like they are off the hook regarding the health effects of their weight.  This is the first study I’ve seen that shows this may not be the case.  You need to be at a healthy weight/bmi and waist size. 

Take Home Message:  If you are at a normal weight and BMI, good for you.  Also make sure your waist circumference is below normal limits.

Measure your waist circumference at your belly button.  The cut offs for abdominal obesity is 88 cm (34.6 inches) for women and 102 (40.2 inches) for men.  Be well below this level!

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