June 9, 2006

Joint and Muscle Problems for Overweight Youth

photo of an overweight youth

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 new study from NIH's National Institute of Child Health and Human Development. Overweight youth in the study were also more likely than non-overweight youth to develop changes in the knee joint that make movement more difficult.

A total of 355 Washington, D.C. area children and adolescents took part in the study. Of these, 227 were classified as overweight and 128 as non-overweight. The children underwent a detailed physical examination and were questioned about whether they had experienced any joint, bone or muscle-related problems. They also provided answers to a questionnaire designed to gauge the impact their weight had on their quality of life, ranking on a 5-point scale whether statements about impaired mobility applied to them. The statements included: “I have trouble using stairs,” “I feel clumsy or awkward,” and “I have trouble getting up from chairs.” In addition, the researchers used a technique called Dual Energy X-Ray Absorptiometry (DXA) to detect any effects of being overweight on the feet, ankles and knees.

The results were published in the June 2006 issue of Pediatrics. The researchers found that the overweight youth were more likely to experience bone fractures and muscle and joint pain than those who weren’t overweight. The most common joint complaint was knee pain, with 21.4% of overweight youth reporting knee pain, compared to 16.7% of non-overweight youth. The overweight youth were more likely to report impaired mobility as well. DXA scans showed that overweight youth were also more likely to experience changes in how the bones of the thigh and leg meet at their knees.

The researchers noted that, while overweight children and adults have a greater bone density than their non-overweight counterparts, this greater density didn’t protect the youth in the study from bone fractures. This may be because someone who’s overweight can fall with greater force than someone who isn’t. Other studies have suggested that overweight boys also have poorer balance than non-overweight boys, and so are more likely to fall.

“Bone, muscle and joint problems are particularly troubling in this age group,” NIH Director Dr. Elias A. Zerhouni said. “If overweight youth fail to attain normal weight, they will likely experience an even greater incidence of these problems when they reach later life.” NIH has developed a variety of on-line materials to help young people make healthy choices about diet and exercise.

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