Comparison of serum 1,25-dihydroxycholecalciferol concentrations in rheumatoid arthritis and osteoarthrosis.

We have previously compared 25-hydroxycholecalciferol levels in the serum of patients with osteoarthrosis and rheumatoid arthritis, finding no significant difference between the circulating levels of this hormone. We have now estimated 1,25-dihydroxycholecalciferol levels on stored sera from the same groups of patients and found no significant difference in the levels of this hormone between the 2 groups. The osteopenia that distinguishes rheumatoid arthritis from osteoarthrosis is not the result of altered levels of systemic 25OHD3 or of 1,25(OH)2D3. Local factors may be more important in its pathogenesis.