Causal effects of lifetime smoking on breast and colorectal cancer risk: Mendelian randomization study
Background: Observational evidence has shown that smoking is a risk factor for breast and colorectal cancer. We used Mendelian randomization (MR) to examine causal associations between smoking and risks of breast and colorectal cancer. Methods: Genome-wide association study summary data were used to identify genetic variants associated with lifetime amount of smoking (n=126 variants) and…