Zhang L, Wang L, Li Y, et al. - Given that the combustion of tobacco or high-temperature cooking of meats generates heterocyclic aromatic amines (HAAs), and 2-Amino-9H-pyrido[2,3-b]indole (AαC) represents a main carcinogenic HAAs in tobacco smoke, researchers analyzed spot urine samples from adult members of the 2013-2014 cycle of the NHANES (N = 1,792) in order to determine urinary AαC in these samples, considering it as a marker of AαC exposure. Based on self-report and serum cotinine data, they discriminated exclusive combusted tobacco smokers from non-users of tobacco products. They found 40 times higher sample-weighted median urinary AαC among exclusive smokers vs non-users. A significant rise in urinary AαC related to eating beef cooked at high temperature and a decreased AαC in correlation with consuming vegetables was observed in non-users. Controlling for potential confounders, a significant rise of 23.6 pg AαC/mL calculated at geometric mean of AαC was noted in relation to smoking one-half pack of cigarettes per day. Findings revealed that tobacco smoke, as well as certain dietary components (to a lesser extent), are the sources of AαC exposure in both exclusive smokers and non-users of tobacco in the general US population.