Association between baseline serum α-tocopherol and γ-tocopherol and risk of prostate cancer, stratified by smoking status, PLCO Study.

aMultiplicative interaction tested using the log-likelihood ratio, comparing models with and without an interaction term of tocopherol quintiles crossed with a categorical smoking status variable. bNumbers are cases/controls. cValues are odds ratios (95% confidence intervals), based on unconditional logistic regression and adjusted for study center, serum cholesterol, serum β-carotene, age, time since initial screening, and year of blood draw.