CHICAGO – Rheumatoid arthritis more than doubles the risk of fracture in women younger than age 50, according to the results of a large population-based study.
While it’s well known that the disease drives up fracture risk in older men and women, independent of glucocorticoid use, these findings suggest that "we need to make our [younger female] patients aware" that they, too, are at increased risk so they can take precautions by not smoking, and by maintaining adequate calcium, vitamin D, and activity levels, Dr. Shreyasee Amin said at the annual meeting of the American College of Rheumatology.
Dr. Amin and colleagues at the Mayo Clinic in Rochester, Minn., analyzed data from the Rochester Epidemiologic Project, which includes inpatient and outpatient medical records for residents of Olmstead County, Minn.
The population-based cohort included 1,171 women (70%) and men (30%) diagnosed with RA during 1955-2007. Those individuals were compared with age- and sex-matched controls without RA. The researchers followed subjects until death or their last available follow-up.*
Among women with RA, 308 were younger than 50 years; among men with RA, 110 were younger than 50 years.
Causes of fractures were categorized by whether they were incidental or not and by trauma severity: severe (for example, motor vehicle accident), moderate (fall from standing height or less), spontaneous, and pathologic (malignancy). Severe or pathologic fractures were not included in the analysis.
Overall, women with RA had a 63% greater risk of fracture than women without RA. Women with RA aged 50 years or older had a 43% greater risk of fracture, and women younger than 50 years had more than twice the risk of a fracture (Hazard Ratio, 2.34).
Overall, men with RA had a 40% greater risk of a fracture, compared with those without the disease. Among men aged 50 years and older, those with RA tended to have a greater risk of fracture. In men with RA who were younger than age 50, "we didn’t see enough fractures to determine whether they were at high risk for fracture before the age of 50," said the rheumatologist.
Steroids, which are commonly used to treat the disease, can put individuals at greater risk of fracture. But RA patients also tend to have a greater risk of fracture, independent of their steroid use. "The disease itself may play a role in the loss of bone because the inflammation that drives the joint disease also affects the cells of the bone that increase bone loss," she said.
The study primarily involved a white population, so the results can’t be extrapolated to other races or ethic groups with RA.
Dr. Amin reported that she is on the scientific advisory board for Merck.
* Correction, 11/10/2011: The original version of this story misstated how patients in this study were followed. Patients were followed until death or their last available follow-up, not their first fracture.