A randomized controlled trial of calcium supplementation to increase bone mineral density in children with juvenile rheumatoid arthritis

Objective. To examine the effects of daily supplementation with calcium (Ca) in combination with vitamin D on total body and lumbar spine bone mineral density (BMD) in patients with juvenile rheumatoid arthritis (JRA) who had not taken corticosteroids for at least 3 months prior to the beginning of the study. Methods. One hundred ninety-eight children and adolescents (141 girls and 57 boys) with JRA, ages 6 to 18 years, with a mean +/- SD age of 11.7 +/- 3.3 years and a mean +/- SD disease duration of 5.6 +/- 3.8 years at the beginning of the study, were enrolled in this randomized double-blind, placebo-controlled trial to receive either daily oral supplements of 1,000 mg of Ca and 400 IU of vitamin D (n = 103) or matched placebo tablets and 400 IU of vitamin D (n = 95) for 24 months. Total body BMD (TBBMD) was measured by dual x-ray absorptiometry at baseline and every 6 months for 24 months. Results. At baseline, the mean +/- SD TBBMD was 0.89 +/- 0.14 gm/cm(2) among patients randomized to the Ca group and 0.87 +/- 0.14 gm/cm(2) among those randomized to placebo (P = 0.445). At 24 months, the mean SD TBBMD among those receiving Ca was 0.95 +/- 0.13 gm/cm(2). compared with 0.92 +/- 0.14 gm/cm(2) among those receiving placebo. A longitudinal random-effects mixed model analysis that controlled for differences in the subject's initial BMD, sex, Tanner stage, adherence to the study medication regimen, and body composition revealed significantly higher TBBMD among patients who received Ca compared with patients who received placebo during the study period (P = 0.03). Conclusion. Ca supplementation resulted in a small, but statistically significant, increase in TBBMD compared with placebo in children with JRA.