Figure 2.

Estimated excess relative risk/pack-year (ERR/PKY) for coronary heart disease within categories of cigarettes/day (solid symbol, with 95% confidence interval) and fitted models for pack-years and cigarettes/day for each cohort (solid line, with shaded area identifying the pointwise 95% confidence interval) and for a model using the inverse variance weighted parameters (dash line). Data are from the Agricultural Health Study (AHS), with the figure showing one imputation, and the Alpha-Tocopherol, Beta-Carotene Prevention Study (ATBC).