More recently, Jiag’s group has reported the positive correlation between urinary copper and the serum markers of chronic respiratory diseases (CRDs, including asthma, COPD, lung cancer, and emphysema), such as cytokines (IL-6, IL-8), and circRNAs in a case-control study (n = 101, 161; case vs. control). The gene discussed is CXCL8; the disease is asthma.