Individuals at higher genetic risk accumulated more pack-years across 38 years of follow-up. Results from an OLS model indicated that each one-unit increase in the GRS predicted an additional pack-year in lifetime cigarette consumption among ever-smokers (B=1.05 [0.36-1.73]) (Figure 4 Panel A). We also analyzed the persistence of heavy smoking as the number of assessments at which individuals smoked ≥20 cigarettes per day. Individuals at higher genetic risk smoked heavily at more assessments (incidence rate ratio (IRR) for number of assessments as a heavy smoker=1.26 [1.07-1.49]).
