Prevalence of Lower Bone Mineral Density and Its Associated Factors in Korean Children and Adolescents with Juvenile Idiopathic Arthritis

Abstract

Objective. This study examined the prevalence of low-bone mineral density (BMD) and its associated factors in Korean children and adolescents with juvenile idiopathic arthritis (JIA). Methods. Thirty-nine patients with JIA were included in this cross-sectional study. The patients were examined for their bone age (BA) and bone mineral density (BMD). The BMD was measured using dual-energy X-ray absorptiometry on the lumbar spine. Each BMD value was converted to a Z-score by comparing the reference values of the healthy control group in terms of the age and sex of each patient, which was measured using the same device. A Z-score of less than -2.0 was defined as a low BMD. Laboratory tests were performed to detect the serum calcium, phosphorus, alkaline phosphatase, and 25-hydroxyvitamin D levels. Results. The mean age at the time of the examination was 12.2 +/- 3.6 years, and the study comprised a total of 39 patients (16 males, 23 females). Patients with systemic JIA had a lower BMD, which was calculated based on the CA, BA, and HA, than those with non-systemic JIA (P=0.020, P=0.049, and P=0.024, respectively); the corticosteroid user group also showed a lower BMD, which had been calculated based on the CA, BA, and HA, than the corticosteroid non-user group (p=0.002, p=0.022, and p=0.188, respectively). Conclusion. This study suggests that JIA patients have a lower BMD than control subjects. Therefore, treatment, and education are warranted while treating patients with JIA, particularly those requiring oral corticosteroids or those with systemic JIA and appropriate laboratory tests.