High serum prolactin levels in men with rheumatoid arthritis

Objective. High prolactin (PRL) levels have been reported in systemic lupus erythematosus, Reiter's syndrome, and psoriatic arthritis. However, results of PRL investigations in rheumatoid arthritis (RA) are contradictory. We evaluated the PRL status in men with RA and the possible effect on bone mineral density (BMD). Methods, We studied 91 men with RA and 68 controls. PRL serum levels were analyzed under standardized conditions, Sex hormones (testosterone, androstenedione, and DHEAS) were also studied. BMD was analyzed at L2-L4 and the femoral neck by Hologic QDR1000. Comparative tests, linear correlations, and multiple regression analysis were performed. Results, Serum PRL levels were significantly higher in men with RA (249 +/- 162 mU/l) than in controls (189 +/- 85 mU/l) (p = 0.0015). High PRL levels were significantly correlated with the duration of RA (r = 0.23; p = 0.01) and with functional stage according to the Steinbrocker classification (r = 0.24; p = 0.01). High PRL concentrations were not correlated with the low levels of androgens observed in males with RA. Femoral BMD showed a negative correlation with PRL concentrations (r = 0.20; p = 0.04). Nevertheless, PRL was not a significant determinant of BMD. Conclusion. Men with RA have high serum PRL levels and concentrations increase with longer disease evolution and worse functional stage. Prolactin levels do not have a direct effect on BMD.