Blame all you want on genetics, but the unholy trio of cigarettes, alcohol, and an unhealthy diet cause over 40 percent of all cancer cases in the US.

Cigarettes are the main risk factor for cancer, researchers found. Image credits: Sophie Riches.

The American Cancer Society (ACS) published a new paper detailing all the risk factors associated with cancer. Using data from the Centers for Disease Control and Prevention (CDC) and the National Cancer Institute (NCI), researchers documented smoking, secondhand smoke, excessive body weight, high consumption of red meat and processed meat, low consumption of fruits and vegetables, physical inactivity, and alcohol intake as the main factors. Specifically, cigarette smoking was identified as the most dangerous factor, being associated with 19 percent of cases (including 81 percent of lung cancers) and 28.8 percent of deaths. Extra weight was a distant second, being connected to 7.8 percent of cases and 6.5 percent of deaths. Alcohol came in third, while almost all skin cancers can be traced down to severe exposure to the sun or a tanning booth.

In absolute numbers, that accounts for a huge amount of cancer cases. It’s estimated that 21.1 million Americans have been diagnosed with cancer at some point during their lives, with 1,596,486 new cases in 2014 (the last year with available data). To make things even worse, the combination of several environmental risk factors works even worse than the individual sum. Previous studies have found that environmental factors can be blamed for up to 90% of cancer cases.

However, the ACS says that this is encouraging news in a way, because it means that we can avoid a lot of cancers. All it takes is to have a healthier lifestyle. Preventive strategies can make a big difference, they explain.

“Increasing access to preventive health care and awareness about preventive measures should be part of any comprehensive strategy for broad and equitable implementation of known interventions to accelerate progress against cancer.”

The ACS also has a number of useful tips on staying healthy and avoiding cancer on their website. This includes, of course, giving up smoking and opting for a healthier diet, but it also suggests taking regular screenings, especially if you are at a high risk.

Journal Reference: Farhad Islami et al. Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States. DOI: 10.3322/caac.21440