To study bioavailable testosterone (T) in men with rheumatoid arthritis (RA) by determining non-sex hormone-binding globulin (SHBG)-bound T (NST) under standardized conditions and to investigate if NST is related to disease variables.
Basal serum concentrations of total T, SHBG and luteinizing hormone (LH) were measured in 104 men with RA, and the levels of NST as well as the quotient T/SHBG were calculated. The data were compared with those of 99 age-matched healthy men. The results were analysed separately for the age groups 30-49, 50-59 and 60-69 yr.
The RA men had lower NST levels than the healthy men in all age groups. T levels and the T/SHBG ratio were lower only in the age group 50-59 yr. SHBG did not differ significantly. LH was significantly lower in the patients than in the controls. Thirty-three of the 104 patients were considered to have hypogonadism compared with seven of the 99 healthy men. The only clinical variable apart from age that had a significant impact on NST was the Stanford Health Assessment Questionnaire (HAQ).
Men with RA had lower levels of bioavailable T and a large proportion were considered hypogonadal. The low levels of LH suggested a central origin of the relative hypoandrogenicity.