Bone of Contention

Several weeks ago, The Journal of the American Medical Association published a study that looked at the incidence of hip fractures among older Americans and the mortality rates associated with them. Although the number of hip fractures has declined in recent decades, the study found that the 12-month mortality rate associated with the injury still hovers at more than 20 per cent. Thus, in the year after fracturing a hip, about one in five people over age 65 will die.

Another group of articles, published last month in Medicine & Science in Sports & Exercise , the journal of the American College of Sports Medicine, underscores why that statistic should be relevant even to young, active people. The articles detailed a continuing controversy about exactly how exercise works on bone and why sometimes, apparently, it doesn’t.

“There was a time, not so long ago,” when most researchers assumed “that any and all activity would be beneficial for bone health,” says Dr Daniel W. Barry, an assistant professor of medicine at the University of Colorado. Then came a raft of unexpected findings, some showing that competitive swimmers had lower-than-anticipated bone density, others that competitive cyclists sometimes had fragile bones and, finally, some studies suggesting that weight-lifting did not necessarily strengthen bones much.