Risk also rises for those who are considered to be underweight
The fatter you are, the more likely you are to die from heart attack, stroke and certain cancers, according to a new study.
Body Mass Index, or BMI, is a number that roughly measures how fat a person is. The new research finds that deaths from all causes go up as BMI increases.
Experts consider a BMI in the range of about 19 to 25 as representing normal weight, and that's about the range where the death rate is lowest.
"So we found that the BMI associated with the lowest risk of death was between about 20 and 25, and that the risk of death increased with increasing BMI," says Amy Berrington of the U.S. National Cancer Institute. "The people in the highest BMI category, which was over about 40, had a two-and-a-half times higher risk than those in the normal BMI range."
Berrington is the lead author of a new paper describing the analysis of death rates and BMI. Death rates go up as BMI numbers increase into the overweight and obese ranges. They also increase, though less so, as BMI decreases into numbers considered underweight.
Age is also a factor. Berrington found that BMI increases have more of a negative impact on middle aged people than on the elderly.
"The older people, the 70 year old, would obviously have a higher risk of dying than the 40 to 50 year old. But the increased risk for dying for the 70 year old was lower than for the 40 to 50 year old," says Berrington.
The massive study included data on almost 1.5 million non-Hispanic white Americans. So one might wonder if the same conclusions would apply to non-whites, or to people living in developing countries. That's a particular concern as Western lifestyles are increasingly adapted elsewhere. Berrington says only that more research is needed.
"We certainly have other studies underway where we want to study it because there is some existing evidence which suggests that the relationship may be different for other ethnic and racial groups."
Amy Berrington's paper on the link between BMI and death rates from all causes is published in The New England Journal of Medicine.