A government study released Tuesday found that people who were overweight at age 50 faced a significantly increased risk of premature death, but the findings were criticized by some researchers as flawed and alarmist.
The study of more than 500,000 U.S. adults found that baby boomers who were even a little overweight faced a 20% to 40% greater chance of dying prematurely.
About 186,000 of those surveyed were excluded from the final results, however, either because they smoked, had a chronic illness or did not respond to the question about their weight at age 50.
“The data was quite strong,” said lead author Dr. Michael F. Leitzmann of the National Cancer Institute, which conducted the study.
The report, released Tuesday by the New England Journal of Medicine, was aimed at resolving a debate over whether being overweight, but not obese, was harmful.
Reaction to the study suggested that the argument was far from over.
Paul Ernsberger, associate professor of nutrition at Case Western University, said the study’s data were narrowly analyzed so that researchers could conclude that being overweight was bad.
“They’re standing on their heads squinting at it backwards trying to make it fit,” he said.
About one-third of Americans are overweight and another third are considered obese, according to the Centers for Disease Control and Prevention. People with a body mass index, or BMI, between 25 and 29.9 are considered overweight, and those with a BMI of 30 or above are considered obese.
Previous studies have shown that obese people have a higher risk of cancer, diabetes, heart disease and premature death.
Overweight people who are not obese are likely to have higher cholesterol and blood pressure, but previous studies have produced conflicting results on whether they face an increased risk of death.
A study last year by researchers from the cancer institute and the CDC found that being slightly overweight might be beneficial.
The latest study, involving 527,265 men and women ages 50 to 71, asked the subjects about their health, diet, smoking habits, height and weight, including their weight at age 50.
The study used age 50 as a benchmark because most people at that age have not developed chronic illnesses that could confound the results. The researchers excluded people who had ever smoked from the analysis to isolate the risk associated only with weight.
Leitzmann said the large number of subjects allowed his team to analyze the data in very detailed slices.
Researchers found that after a decade, the risk of premature death increased two to three times for people who were obese at 50. That finding was essentially the same as in previous studies.
But the study also found an increased risk of death even for those who were just a few pounds heavier than normal BMI range.
The study also revealed significant gender differences. Men considered slightly overweight, with a BMI of 25 to 26.4, faced no risk of premature death. But women with the same BMI did.
“The study shows quite clearly the risk” associated with being overweight, said Dr. Meir J. Stampfer, chairman of the Harvard School of Public Health department of epidemiology.
But Dr. Mitchell Gail, a National Cancer Institute researcher not involved in the study, questioned the validity of basing the study on subjects’ recollections of their weight.
“It’s based on asking people what they weighed when they were 50 years old,” he said. “How accurate was their answer?”
Ernsberger also noted the high number of people excluded from the final analysis, which he said resulted in a selective group of subjects that posed a problem in interpreting the results.