IBD aggressiveness positively correlated with TNF-α (R = 0.50, P = 0.002), and negatively correlated with stability of rest-activity cycles (IS: R = −0.39, P = 0.013) and butyrate-producing bacterium SS3/4 (R = −0.34, P = 0.029). The gene discussed is TNF; the disease is inflammatory bowel disease.