SALT LAKE CITY — As Americans continue to get bigger, you can add knee problems to the list of ailments they are likely to face after lugging around extra pounds.
Being overweight probably leads to more than half of the nation's 850,000 annual operations to repair cartilage tears in the knee, researchers at the University of Utah concluded.
The study, published in a recent edition of the American Journal of Preventive Medicine, focuses on the connection between weight and torn cartilage but doesn't address the exact cause.
Although obesity is hardly a new phenomenon, the list of reasons to stay fit seems to be getting longer.
"I'm afraid there's a lot more we're going to find out," said Dr. Kurt Hegmann, who led the study.
Hegmann, director of the University of Utah's Rocky Mountain Center for Occupational Environmental Health, and his team studied 544 surgical cases involving cartilage tears repaired from 1996 to 2000. The patients were men and women ages 50 to 79 who had surgery on the meniscus, the shock-absorbing cartilage in the knee.
The study found that a person whose body-mass index was even slightly over the healthy range was three times more likely to have a cartilage tear. The heaviest men were 15 times more likely to have torn knee cartilage and women in the same category were 25 times more likely.
"There's a rule in science. When you get numbers this big, there's something going on," Hegmann said.
Nearly two of three Americans are overweight or obese, putting them at risk for a number of related health problems such as high blood pressure, diabetes and sleep disorders, even premature death.
"It's a very wide spectrum," said Dr. George Mensah, acting director of the National Center for Chronic Disease Prevention and Health Promotion.
Mensah hadn't seen Hegmann's study, but said the idea made sense, because people who are overweight or obese put themselves at a greater risk for serious health problems.
Cartilage can break down over time, but Hegmann wanted to explore the connection between meniscal injuries and obesity. He said there are probably several factors involved in the correlation, but he expected it was more than just putting more pressure on the knees.
One possibility is that obese people have circulation problems that reduce the blood supply to the cartilage, he said.
"We're just barely at the point of recognition of the severity of the problem, and we don't have good treatment and prevention strategy, just as we didn't with respect to smoking in the '50s and '60s," Hegmann said.
The study is based only on people who had surgery.