Figure 1. Estimated Associations Between Regular Use of Aspirin and/or NSAIDs and Colorectal Cancer Risk^{a, b, c} .

Abbreviations: OR: odds ratio; 95% CI: 95% confidence interval.

^a The size of the data markers is proportional to the precision of the estimate, which is the inverse of the variance.

^b Study-specific ORs and 95% CIs are estimated using logistic regression models, adjusting for age, sex, education (less than high school, high school graduate or GED, some college, college graduate, graduate degree), first-degree family history of colorectal cancer (yes/no), history of endoscopy (yes/no), postmenopausal hormone use among women (yes/no), history of diabetes(yes/no), body mass index (kg/m²), moderate/vigorous activity (hours/week), smoking (non-smokers and quartiles of pack-years), alcohol intake (none, 1–28g/day, >28g/day), dietary intakes (quartiles) of fruit, vegetables, red meat, processed meat and fiber, total energy intake (quartiles), total (dietary and supplemental) intakes of calcium and folate (quartiles). Covariates in quartiles are adjusted as group linear variables in the model. For aspirin or non-aspirin NSAID use only, the other type was also adjusted for.

^c Subtotal and overall ORs and 95% CIs are estimated using fixed-effect meta-analysis. The estimates using random-effect are: (A) Any aspirin or NSAID use: OR=0.75 (0.67, 0.85) (B) Aspirin use: OR=0.79 (0.70, 0.89) (C) Non-aspirin NSAID use: OR=0.74 (0.64, 0.86).