BETHESDA, MD — Children and adolescents who are overweight are more likely than their normal weight counterparts to suffer bone fractures and have joint and muscle pains, according to a study conducted by researchers at the National Institutes of Health (NIH) and appearing in the June 2006 issue of Pediatrics. Researchers also found that the overweight youth in the study were more likely than non-overweight youth to develop changes in the knee joint that make movement more difficult.

“Bone, muscle, and joint problems are particularly troubling in this age group,” said Elias A. Zerhouni, M.D., NIH director. “If overweight youth fail to attain normal weight, they will likely experience an even greater incidence of these problems when they reach later life.”

Three-hundred-and-fifty-five black and white Washington, D.C. area children and adolescents took part in the study, said the study's senior author, Jack A. Yanovski, head of the Unit on Growth and Obesity at NIH's National Institute of Child Health and Human Development. Of these children, 227 were classified as overweight and 128 as non-overweight. Upon entering the study, the children underwent a detailed physical examination and were questioned about whether they had experienced any joint, bone or muscle-related problems.

The researchers found that the overweight youth were more likely to experience bone fractures and muscle and joint pain than the non-overweight group. The most common self-reported joint complaint was knee pain, with 21.4 percent of overweight youth reporting knee pain and 16.7 percent of non-overweight youth reporting knee pain. The overweight youth were also more likely to report impaired mobility than the non-overweight youth.

In the article, Yanovski and his coworkers noted that while overweight children and adults have a greater bone density than their non-overweight counterparts, this greater density did not protect the youth in the study from bone fractures. Moreover, they wrote, other studies have suggested that overweight boys have poorer balance than non-overweight boys and therefore are more likely to fall.

However, imparied mobility, pain and poorer balance doesn't mean that overweight children can't be active. The authors suggested that significantly overweight children and adolescents should engage in alternative modes of physical activity like swimming to alleviate the severity of lower extremity joint loading and discomfort.