CXCL8 and obesity disorder: Every 2-fold increase in mRNA expression of CXCL8 was associated with 41.4 pg/ml (95%CI = 16.3–66.6 pg/ml, P = 0.0018, n = 52) increase in net CXCL8 protein levels in supernatants using a generalized linear model with adjustment for age, overweight or obesity, current smoking status, packyears, passage of cells, and batch of assay.