individuals of European ancestries (EUR; n = 2,669,029) from the United States, Europe and Australia (see Extended Data Fig. 1 and Supplementary Note). Smoking phenotypes were selected to represent different stages of tobacco use and addiction, including initiation, the onset of regular use, amount smoked and cessation. Measures of onset included whether an individual ever smoked regularly (smoking initiation (SmkInit); n = 3,383,199) and the age at which the individual began smoking regularly (AgeSmk; n = 728,826). Amount smoked among current and former regular smokers was measured as cigarettes smoked per day (CigDay; n = 784,353). Smoking cessation (SmkCes; n = 1,400,535) contrasted current versus former smokers. Alcohol use was widely available across most studies, measured as drinks per week (DrnkWk; n = 2,965,643).
