Effect of Hypo-and euthyroid status on serum cystatin C levels

Objective: the aim of this study was to investigate the effect of hypo- and euthyroid status on serum cystatin c (cysc) levels in children and to explore whether cysc can be used as a marker of the thyroid status. methods: twenty five patients with hypothyroidism (10m,15f; mean age:8.7±4.9 years) and 21 healhty age-matched controls (9m,12f; mean age: 9.7±5.0 years) were included in this study. serum thyrotropin (tsh),free thyroxine (ft4),serum cysc and creatinine levels were studied in patients with hypothyroidism twice,i.e. in the euthyroid (on l-t4) and hypothyroid state,and in controls. results: no significant differences in creatinine,glomerular filtration rate (gfr) and cysc levels were observed between the study group in the euthyroid status and the control group. cysc (mg/dl) level was found to be lower in the hypothyroid status(0.6±0.1) than in the euthyroid status (0.66±0.1) (p=0.01). in hypothyroid status,cysc levels showed a positive correlation with gfr (r=0.463,p=0.02) and gfr had positive correlation with ft4 (r=0.563,p=0.012). conclusions: we demonstrated a significant effect of thyroid dysfunction on cysc levels,but the changes in serum cysc levels in hypo- and euthyroid status did not exceed the reference interval. it may be concluded that serum cysc levels have limited use in evaluating the peripheral effects of thyroid hormones. © journal of clinical research in pediatric endocrinology.