IGF1 and obstructive sleep apnea syndrome: Presence of obstructive sleep apnea increased the odds of developing POD by a factor of 4.60 (95% CI 1.40–15.1; p = 0.012) in the univariate logistic regression analysis and by 4.06 (95% CI; 1.21–13.7; p = 0.024) after adjustment for IGF-I and diabetes.