Smoking and Alcohol
Credit: Heinrich Volschenk / Getty Images

Smoking can cause all different kinds of cancer, especially lung cancer. Lung cancer is the deadliest cancer in the U.S. and 90 percent of cases in men are caused by smoking. Alcohol also raises the risk of several types of cancer, with research suggesting that ethanol is the culprit. So the stronger a drink is, the more it increases your cancer risk. Smoking and drinking combined have an especially detrimental effect, possibly because alcohol makes it easier for tobacco chemicals to enter cells and harder for DNA to repair itself from the tobacco damage.