Relative risk of gastrointestinal bleeding according to dose of aspirin use†.

†Relative risks (RR) are compared to non-users 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 also adjusted for aspirin duration (continuous use in years).§§Multivariate RR model is also adjusted for aspirin frequency (median aspirin frequency of each category as continuous variable).