1. Where you live
A 2017 study published in the journal Cancer found that in the United States, counties with the poorest quality air, water, land, built environment and sociodemographic factors face increased incidence of cancer. Poor air quality and the built environment (presence of major highways, availability of public transit and housing) correlated most strongly with high cancer rates. These findings applied to both men and women, with prostate and breast cancer most strongly associated with poor environment. Other research tells us that minority neighborhoods face a higher risk of cancer due to air pollution.