A long-term study indicates that the measure of waist-to-hip ratio (WHR) is much stronger than BMI as a predictor of all-cause mortality in high-functioning older adults. WHR measures how much larger the waist is than the hips, whereas BMI reflects weight in relation to height (Ann Epidemiol. 2009;19:724-731).
Research was conducted to address the debate over the relationship between obesity and mortality in older adults. Whereas other investigators believe that the BMI threshold for obesity should be higher for older adults than for young and middle-aged individuals, these investigators explored the question of whether BMI is even the appropriate measure of obesity for older people.
The analysis involved 12 years’ worth of all-cause mortality data from the MacArthur Successful Aging Study, which evaluated more than 4,000 men and women who were aged 70-79 years at enrollment. Participants had relatively high measures of physical and cognitive functioning.
After comparing mortality rates based on patients’ BMI, WHR, and waist circumference, the group found no association between all-cause mortality and BMI or waist circumference; the only link was seen with WHR. In women, each 0.1 increase in WHR translated to a 28% relative increase in mortality rate. In men, the rate of dying was 75% higher for those whose waists were larger than their hips compared with those whose waist size was equal to or smaller than their hip size.
The authors acknowledge that their findings could have been skewed by use of self-reported height and weight data.