Nicotinic acetylcholine receptor subunit genes code for proteins that form receptors present in neuronal and other tissues, such as alveolar epithelial cells and pulmonary neuroendocrine cells, and bind to nicotine (14). Sequence variants in this cluster of genes on chromosome 15 have been associated with increased (self-reported) cigarette dose and nicotine dependence (2). Our study, which uses nicotine equivalents as a more accurate reflection of tobacco smoke exposure than self reported cigarettes per day, further indicates that carriers of these variants smoke more intensively, resulting in higher exposures to nicotine, to NNK and most likely to other tobacco smoke carcinogens.
