IGF1 and obstructive sleep apnea syndrome: Multivariate regression analysis also resulted in IGF-I as a non-significant risk factor for POD (OR = 0.985, 95% CI: 0.964, 1.007; p = 0.183) after adjustment for obstructive sleep apnea (p = 0.024) and diabetes (p = 0.273) (Table 2).