Childhood arthritis increases the risk of fractures, particularly during adolescence, according to a large study of British patient records. The researchers say that more targeted treatments promoting bone health would benefit patients with childhood-onset arthritis throughout their lifespan.
In addition to raising the risk of fracture during childhood, the researchers also found that childhood-onset arthritis potentially heightens fracture risk after age 45.
A research team led by pediatric rheumatologist Jon M. Burnham, M.D., of The Children's Hospital of Philadelphia and the University of Pennsylvania, analyzed the medical records of 1,959 patients in the United Kingdom who first experienced arthritis between ages one and 19. The researchers compared those patients to a larger control group of 207,000 patients in a primary care database.
The study appeared online in the Annals of the Rheumatic Diseases on April 21. It was the first research to examine, in a population-based study, the risk of fractures in childhood arthritis patients.
Juvenile idiopathic arthritis (JIA), also called juvenile rheumatoid arthritis, is the most common pediatric rheumatic disease, affecting approximately one in 1,000 U.S. children. It was already known that low bone mass occurs in patients with JIA, because of risk factors such as chronic inflammation, delayed puberty, malnutrition, weakness, inactivity and treatment with steroid medications.
"The goal of this study was to determine if the bone abnormalities seen in JIA are clinically significant, resulting in higher fracture rates, and that is exactly what we found," said Dr. Burnham. "The low bone mass in JIA is associated with skeletal fragility, and causes both short-term and long-term health problems. Someone who fails to attain peak bone mass during adolescence and young adulthood is more vulnerable to fractures in later life, when bone mass inexorably declines."
Fractures are not unusual in healthy, active children, and the researchers compared the records of patients who had juvenile-onset arthritis with those of control subjects. Their data source was the United Kingdom General Practice Research Database, representing primary care records from 1987 to 2002.
The researchers found that 6.7 percent of patients with JIA sustained first fractures, compared to 3.3 percent of control subjects with first fractures, during an average follow-up period of four years. The comparative risk for patients with arthritis was highest at ages 10 to 15 and peaked again after age 45. Patients with arthritis were significantly more likely than controls to suffer fractures in their arm and leg bones.
Dr. Burnham added that the study findings should encourage physicians caring for children with arthritis to more closely monitor their patients for signs of osteoporosis, and to focus on nutritional steps that promote bone health, such as increasing regular intake of calcium and vitamin D.
Because bone health is affected by a combination of factors, including inflammation, inactivity, delayed puberty, impaired nutrition and the use of steroid medications, he added, further studies should concentrate on determining how JIA interacts with these risk factors, and how specific therapies might benefit JIA patients. Dr. Burnham is currently leading multidisciplinary research on bone and muscle strength in JIA and other inflammatory diseases.
The Nickolett Foundation for JRA Research funded the study. Dr. Burnham's co-authors were Mary B. Leonard, M.D., of The Children's Hospital of Pennsylvania; and James D. Lewis, M.D., Justine Shults, Ph.D., and Rachel Weinstein, Ph.D., of the University of Pennsylvania School of Medicine. All the authors are on the faculty of the Penn School of Medicine and of the Center for Clinical Epidemiology and Biostatistics at Penn.
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