When performing subgroup analysis based on sample source, in serum, the difference between the level of omentin in OSA patients and the level of control group was statistically significant, and the expression in OSA patients was lower (SMD = −2.07, 95% CI = −2.61 to −1.54, p < 0.001). The gene discussed is ITLN1; the disease is obstructive sleep apnea syndrome.