WINNIPEG, Canada—Hip fracture rates in Canada have been declining since 1985, with a more rapid drop between 1996 and 2005 and a more marked decrease among individuals age 55 to 64 years, according to a new study in the August 26 issue of the Journal of the American Medical Association.¹ Similar trends have been reported in other countries, including the United States.

Exactly why this is occurring is unclear, but “the decreasing incidence rates are not grounds for complacency toward osteoporosis prevention and treatment,” conclude researchers who were led by William D. Leslie, MD, MSc, of the University of Manitoba, in Winnipeg, Canada. “Hip fractures continue to exert major effects on the population, particularly the elderly, and on the health care system, related to the morbidity, costs and mortality from these fractures.”

The percentage rates decreased, but the absolute number of hip fractures increased over the study period due to the changing age structure of the population, the study authors note.

The researchers analyzed nationwide hospitalization data from the Canadian Institute for Health Information for 1985 to 2005. During this time period, a total of 570,872 individuals were hospitalized for hip fracture. Over the 21 years, age-adjusted rates of hip fracture declined 31.8% in females and 25% in males. The largest percentage decrease was seen among individuals age 55 to 64 years. Specifically, hip fracture rates decreased by almost one-half in females and about one-third in males in this age range.

A more rapid decline began around 1996, the study showed. The average age-adjusted annual percentage decrease in hip fracture rates was 1.2% per year from 1985 to 1996 and 2.4% per year from 1996 to 2005, the study showed.

The decline in hip fracture rates began before the widespread availability of bone density testing or pharmacological treatments for osteoporosis. Moreover, there is little evidence to suggest that improvements in physical activity, calcium intake, vitamin D status, or prevention of falls are responsible for the declining rates of hip fracture seen in this study.

Translating research into practice: Preventing hip fracture

Edward Puzas, PhD, a professor of orthopedics at the University of Rochester at Rochester, NY, has a theory on the reasons behind the decline in hip fracture rates in Canada and elsewhere.

“The early- and mid-80s was the heyday of hormone replacement therapy (HRT) and estrogen replacement therapy and HRT did show a substantial decrease in hip fractures in females,” Dr. Puzas told MSKreport.com. HRT fell from grace when the Women’s Health Initiative was stopped early in 2002 because the risks—including an increased risk of breast cancer, stroke, heart disease, and blood clots in their lungs and legs—were shown to outweigh the benefits of HRT, including the reduction in hip fractures.

In the mid-1990s, bisphosphonates became popular, he added. “HRT decreased fractures and then women were switched over to these more effective drugs, and we saw a greater decline,” he said. “Obesity could also be a contributing factor.”

“This is preventive medicine at its best,” he said of the new study findings. Still, Dr. Puzas is concerned that projected Medicare cuts to reduce reimbursement for dual X-ray absorptiometry (DXA) may reverse these gains. “The diagnosis and prevention of osteoporosis should be a priority,” he said. “I am pleased to see the data and think we need to keep doing what we are doing.”

Reference

1. Leslie WD, O’Donnell S, Jean S, et al. Trends in hip fracture rates in Canada. JAMA. 2009;302:883-889.