Osteoporosis in juvenile systemic lupus erythematosus: a longitudinal study on the effect of steroids on bone mineral density

Abstract

Peak bone mass is an important determinant of future bone mass and of the risk of osteoporosis and subsequent fractures. Although some information concerning bone mineral density (BMD) in adults affected with systemic lupus erythematosus (SLE) is available, few data on children and adolescents have been reported. Many variables, such as duration and activity of the disease, reduced sun exposure, and steroid therapy have been suggested as risk factors in the pathogenesis of osteoporosis in SLE. In this study, we longitudinally evaluated, by dual energy X-ray absorptiometry (DEXA), the BMD of 20 young patients affected with juvenile SLE (JSLE), in order to establish the degree of osteoporosis and the influence of steroid treatment, among other clinical variables. At baseline, the mean BMD in JSLE patients was 0.978 g/cm2 and in controls 1.038 g/cm2 (P = 0.31). At 1 year (time 2), this value became 0.947 g/cm2 in JSLE children; the mean individual difference was 0.28 g/cm2 (3.4%). Only in those patients aged 19-25 years BMD was significantly lower than in controls, both at baseline and at time 2. Considering the steroid treatment, no significant difference between the two groups was found either at baseline or at time 2; however, the mean yearly BMD loss in the steroid patients was 0.031 g/cm2 (3.5%) vs. 0.005 g/cm2 (0.5%) in those who had not taken steroids. A significantly inverse correlation between BMD and the cumulative dosage of corticosteroids has been detected. BMD produced a significantly inverse correlation to the cumulative dosage of corticosteroids; no significant correlation has been found between BMD and disease activity or duration.

Prevalence and etiology of low bone mineral density in juvenile systemic lupus erythematosus

“…Two previous studies in juvenile SLE showed that BMD was correlated with cumulative corticosteroid dose, but the study populations included adults with childhood-onset SLE, as well as children (2,14). Consistent with our findings are the results of studies in adult premenopausal patients with SLE, in which decreased BMD was not found to be correlated with corticosteroid use, total corticosteroid dose, or duration of corticosteroid use (29)(30)(31)(32)(33)(34)(35)(36)(37).…”

“…The major difference between our study and previous investigations in juvenile SLE is that the sample size of pediatric patients in our study was larger than those in the earlier studies in which lower BMD in patients with juvenile SLE was also demonstrated (14,16). Consistent with our results were the findings of 2 studies of patients who were Ͼ19 years old at the time of study but whose SLE had begun during childhood, both of which demonstrated decreased BMD (2,14). While the frequency of osteopenia was comparable (14), the frequency of osteo- Disease duration (0.0028), lupus nephritis (0.0541) Correlation with hip BMD Ͻ80% Disease duration (0.0249) * Three separate multivariate analyses using 2 of 3 interrelated variables at a time were performed.…”

“…Although osteoporosis is a well-known complication of adult-onset SLE, few studies have been performed in juvenile SLE (2,(14)(15)(16). In contrast to studies of juvenile dermatomyositis (11) and juvenile idiopathic arthritis (9,12,13,27,28), which have shown decreased BMD in these patients, only 2 of 4 studies of juvenile SLE demonstrated decreased BMD (14,16).…”

“…Despite the more severe disease course of juvenile SLE, however, there has been significant improvement in long-term mortality. Therefore, more studies have focused on long-term morbidities, specifically, premature atherosclerosis and osteoporosis leading to insufficiency fractures (2)(3)(4).…”

“…These concerns are particularly important in juvenile SLE, since these patients tend to have severe chronic inflammation and frequently receive prolonged courses of high-dose corticosteroid therapy. Despite these concerns, there have been few studies examining osteoporosis and the development of fragility fractures in patients with juvenile SLE (2,(14)(15)(16). The aim of the present study was to identify risk factors associated with osteoporosis in this patient population.…”