Genotype Cannot Be Raised by a Tumour

Resting heart rate predicts cancer mortality observationally, and the meta-analysis authors say plainly they cannot tell whether it is a marker of subclinical disease or a cause. Mendelian randomisation can: genotype is fixed at conception, so reverse causation is unavailable by construction. The instrument existed and nobody had pointed it at cancer. Run here on 278 variants against 76,192 breast…