We examined the relationships existing between serum cytokine levels and bone mineral density (BMD) in women of premenopausal age affected by Graves' disease with subclinical hyperthyroidism. The study population consisted of 21 women with untreated hyperthyroid Graves' disease (group H) (age, 36 +/- 2 years), eight women with untreated subclinical hyperthyroid status (group SH) (age, 33 +/- 5 years) and 10 healthy women (group N) (age, 35 +/- 3 years). The following measurements were made in all patients: free T-4 (fT(4)), free T-3 (fT(3)), thyroid stimulating hormone (TSH), TSH receptor antibody (TRab), anti-thyroid peroxidase antibody (anti-TPO), anti-thyroglobulin antibody (anti-Tg), interleukin-2 receptor (IL-2r), interleukin-4 (IL-4), interleukin-8 (IL-8) and interleukin-13 (IL-13). IL-2r and IL-8 levels significantly increased in group H compared with group SH (p < 0.01 and p = 0.05, respectively) and group N (p < 0.001 and p = 0.02, respectively). IL-4 and IL-13 levels tended to be lower in groups H and SH compared with group N, although this difference did not reach statistical significance. Bone mineral density was significantly reduced in only two areas of the femur in group H compared with group N. There was no difference in BMD between groups SH and N. There was no correlation between thyroid hormones, serum cytokine levels and BMD in either group. In conclusion, these results suggest that there were no relationships existing between the serum level of these cytokines and BMD in women of premenopausal age affected by Graves' disease with subclinical hyperthyroidism.