How does smoking make existing health risks worse?

Unfortunately, when you smoke, the dangers posed by smoking interact with other potential health problems, causing your odds of an event occurring to increase exponentially. For example, if you come from a family with a history of heart and arterial disease and you smoke, you have fifteen times the risk of heart attack as someone from the same family who does not. Similarly, if you have high cholesterol and you smoke, you have a risk level of thirty-five times of a heart attack as someone with high cholesterol who does not. Alcohol and cigarettes are another deadly combination: People who drink alcohol and smoke are at much higher risk of mouth, throat, and liver cancers than people who do either one or the other. Alcohol causes the body to make enzymes that metabolize tobacco smoke into highly carcinogenic substances.