Serum S100B protein: a useful marker in obstructive sleep apnea syndrome

Background and purpose: We aimed to underline the importance of serum S100B protein as a useful biochemical marker in patients with obstructive sleep apnea syndrome (OSAS). Material and methods: Forty-three newly diagnosed patients with OSAS (median apnea-hypopnea index [AHI, events/hour]: 37.5 [range 11.3-137]) and 25 subjects with AHI < 5 (median AHI: 4.4 [range 0.7-4.8]) were included in the study. Serum S100B protein level was tested in serum samples taken after polysomnography in both groups and the difference between OSAS patients and the control group regarding that level was assessed. In addition, the association of S100B protein serum level with age, body mass index, AHI, mean O-2 saturation percentage during sleep, minimum O-2 saturation value (%) at the end of the apneas, and the time spent at an O-2 saturation less than 90% were analyzed in the OSAS patient group. Results: Median serum S100B protein level was 133.7 pg/mL (range 20.97-230.70 pg/mL) in patients with OSAS and 16.1 pg/mL (range 10.1-22.9 pg/mL) in the control group (p < 0.005). Serum S100B protein level did not correlate with any studied variable (p > 0.05 for each correlation coefficient). Conclusions: Serum S100B protein level is increased in patients with OSAS and may be a useful biochemical marker in those patients.