POMC and irritable bowel syndrome: Correlation analysis between the first Eigenvariate and ACTH-AUC revealed that this significant interaction effect was driven by a significant negative association in control subjects (r = −0.701, t = 4.99, p = 0.00004), as well as a non-significant positive association in patients with IBS (r = 0.35, t = 1.77, p = 0.09).