ZINC-METABOLISM IN RHEUMATOID-ARTHRITIS - PLASMA AND URINARY ZINC ANDRELATIONSHIP TO DISEASE-ACTIVITY

Objective. To study zinc absorption in patients with active rheumatoid arthritis (RA). Methods. We studied zinc tolerance tests and 24 hour urinary zinc excretion before and after ingestion of 50 mg elemental z inc in 8 healthy volunteers (Group 1) and 13 patients with low RA acti vity (Group 2) and 16 patients with high RA activity (Group 3). R Resu lts. In Group 1, plasma zinc rose from 111+/-7 mu g/dl to a peak of 20 0+/-24 mu g/dl (mean+/-SEM) in 2 h. In Groups 2 and 3, plasma zinc bef ore zinc ingestion was significantly lower than that of the control gr oup (p <0.00001 for both groups) and showed no significant increase in plasma after ingestion. Twenty-four hour urinary zinc excretions befo re and after zinc ingestion were significantly lower (p <0.01, p <0.00 01 for Group 2; p <0.05, p <0.01 for Group 3, respectively) than those in the control group. Conclusion. These results are compatible with z inc malabsorption and consequent zinc deficiency in patients with RA. Whether zinc deficiency contributes to perpetuation of disease activit y by compromising cellular immune function needs further investigation .