New Study Questions Validity of Currently-Accepted Standard in the Elderly

According to British researchers the body/mass ratio (BMR)*, a measurement that is central to practically all medical research in which the patient’s weight is considered to be a factor, may not be as accurate a predictor of future morbidity in patients aged 75 and older as once thought

Instead of the BMI the study used the ratio of the circumference of the waist and of the hips to evaluate its value in predicting future morbidity and mortality in the elderly.

“Guidelines for optimal weight in older persons are limited by uncertainty about the ideal BMI or the usefulness of alternative ... [measures]" writes lead researcher Gill M. Price, MD. "The usefulness of waist circumference (WC) or the Waist/Hip Ratio (WHR) as a predictor of mortality in older persons is also not established."

In the study, which appears in the August issue of the American Journal of Clinical Nutrition, 14,833 volunteers aged 75 years or older were recruited in the United Kingdom. A complete baseline health assessment included measurement of BMI and waist and hip circumferences.

After a median follow-up period of 5.9 years the study found that there had been 6,649 deaths (46% due to circulatory diseases). Surprisingly, both the BMI and waist circumference were not accurate predictors of future morbidity and mortality. However an elevated WHR, or an increasing WHR as compared to baseline measurements, was found to correlate with death from circulatory conditions in both men (WHR > 0.99) and women (WHR > 0.90).

Although the researchers were quick to point out that there findings would require additional study and verification by other investigators, they did state that “current guidelines for BMI-based risk categories overestimate risks due to excess weight in persons aged ≥75 years... Increased mortality risk is more clearly indicated for relative abdominal obesity as measured by high WHR."

The Index Medicus citation for this study is Am J Clin Nutr. 2006; 118:669-682. An abstract (brief summary) can be read online at this link.