Relative risk of gastrointestinal bleeding according to duration of regular aspirin use†.

†Relative risks (RR) are compared to those without any continuous aspirin use as reference group.*Includes 101 individuals with unknown or unspecified location of GI bleeding.**P trend calculated using median aspirin dose of each category as continuous variable.‡Multivariate RR model is adjusted for age, NSAID use (yes or no), smoking status (never, past, current), body mass index (2), exercise (§Multivariate RR model is adjusted for aforementioned variables as well as aspirin dose (continuous use in tablets per week).