IGF1 and obstructive sleep apnea syndrome: Sixteen studies were based on comparisons of serum IGF-1 concentrations between patients with OSAHS with a mean AHI score< 30 and those of patients in the control group, which indicated that serum IGF-1 concentrations in these patients were greatly reduced compared with those of subjects in the control group (SMD=-0.95, 95%CI= -1.38–0.51, P< 0.001, Table 4).