The researchers — with the Cass Business School of City University London and Ashwell Associates — say measuring a person’s waist-to-height ratio is a more accurate predictor of early death risk than the commonly used body mass index (BMI) and should be used in its place, Medical Xpress reports.
 

They issued the call after comparing waist-height ratios with total obesity (as measured by BMI) on life expectancy, analyzing more than 20 years of health data for non-smoking men and women in the U.K. The results showed a stronger link between lower ratios and mortality than BMI and death rates.
 

"There is now overwhelming evidence that government policy should place greater emphasis on [waist-height ratio] as a screening tool," said Les Mayhew of Cass Business School. "Current … policy tends to be restricted to BMI and, to a lesser extent, waist circumference. Focusing on [ratios], which is more globally useful than waist circumference, will identify those with central obesity and ensure resources are focused on those most at risk."
 

To quantify the number of years of life lost to obesity as measured using the ratio, they cited the example of actors Arnold Schwarzenegger and Danny De Vito in the movie "Twins." Both actors have a BMI of 34. If BMI is used as the measure of obesity both stand to lose 3.6 years of life.

But using the waist-height ratio, they calculated that Schwarzenegger (who has a lower ratio) would not expect to lose any years of life whereas De Vito (who has a bigger ratio), could be expected to lose 5.8 years.
 

This is true even though Schwarzenegger has a higher BMI due to muscle (De Vito has the same level of BMI but due to fat).
 

According to the authors, the average 30-year-old man, standing 5-foot-10-inches tall should have a waist of no more than 35 inches. This would put him in the healthy category. If his waist expanded to 42 inches — 60 percent of his height — he risks losing 1.7 years of life. If it grew to 56 inches he could die 20.2 years earlier.
 

An average 30-year-old woman, standing 5-foot-4-inches tall woman risks dying 1.4 years earlier if she let her waist increase from half her height, 32 inches, to 60 percent of her height (38.4 inches). If her waist increased to 51 inches, she could die 10.6 years earlier.
 

"This latest study on years of life lost further supports the very simple global message: "Keep your waist circumference to less than half your height," said Margaret Ashwell, M.D., director of Ashwell Associates.