Bone mineral density and vitamin D in patients with sarcoidosis

Imbalance of calcium homeostasis has ben frequently detected in sarcoidosis patients. In our previous study abnormal metabolism of calcium was detected in about 40% of the patients. In the current study, bone mineral density (BMD) was investigated in relation to serum concentration of calcium and vitamin D.

Consecutive groups of fifteen men (40 +/- 12 years, as mean +/- SD) and 18 women (51 +/- 11 years) with histologically proven sarcoidosis who had not been treated with corticosteroids prior to the study were studied together with control groups. BMD was measured with dual-energy X-ray absorptiometry (DXA) of lumbar vertebrae, and the Z score was calculated to avoid bias of sex and age. Serum concentrations of ionized calcium (s Ca2+), 1,25-Dihydroxyvitamin D (s1, 25(OH)2D3) and osteocalcin (sOC) were measured at the same time.

In women with sarcoidosis only, sCa2+ and s1,25(OH)2D3 showed inverse correlations with Z score of BMD (r = 0.482, p < 0.05 and r = -0.635, p < 0.01, respectively), and s1,25(OH)2D3 showed a positive correlation with sOC (r = 0.658, p < 0.01). Multiple regression analysis showed that age and s1,25(OH)2D3 were the contributory factors to BMD in female patients. Such a significant correlation was not observed in men with sarcoidosis or controls.

1,25(OH)2D3 seemed to be contributory to accelerated turnover of the bone and reduction of BMD in women with sarcoidosis.