Long-term daily aspirin use was associated with lower overall cancer incidence than no use in men (multivariable-adjusted RR = 0.84, 95% confi dence interval [CI] = 0.76 to 0.93) and women (multivariable-adjusted RR = 0.86, 95% CI = 0.73 to 1.03), although the association was not statistically signifi cant in women ( P = .10) (T able 2 ).
These multivariable-adjusted rate ratios were slightly lower than those adjusted only for age (in men, ageadjusted RR = 0.85, 95% CI = 0.77 to 0.94; in women, age-adjusted RR = 0.91, 95% CI = 0.77 to 1.08). Current use of adult-strength aspirin for less than 5 years was not associated with overall cancer incidence in either men or women.
The absolute cancer incidence rate per 100 000 person-years (standardized to the age distributions of men and women in the study using 5-year age categories) was 1858 among men with long-term daily aspirin use, 2163 among men who never reported using aspirin, 1083 among women with long-term daily aspirin use, and 1169 among women who never reported using aspirin.