There is no safe level of tobacco use and smoking behavior. Thus the greatest health outcomes are associated with having never smoked.
Approximately eight million people per year die from smoking-related diseases, with approximately 70% of all lung cancer cases being directly caused by smoking. It also causes cancer in many other areas of the body, including the esophagus, mouth, throat, pancreas, stomach, and liver. Smoking damages the heart tissue and circulation, increasing the risk of coronary heart disease, stroke, vascular disease, and myocardial infarction.
Additionally, smoking damages lung tissue, leading to chronic obstructive pulmonary disorder and pneumonia and worsening respiratory disorders symptoms.
A moderate level of alcohol consumption translates to between one and two drinks per day for men and one drink per day for women. Consuming alcohol above these levels increases the risk of poor health outcomes. For example, over-consumption can raise triglycerides in the blood, increasing the risk of heart attack and stroke. It can also lead to high blood pressure, cardiomyopathy, and cardiac arrhythmia.
Given the role the liver plays in neutralizing toxic substances in the body, it is particularly vulnerable to alcohol. Alcohol-related liver diseases such as fatty liver develop in most individuals who regularly consume excessive levels of alcohol. In serious cases, the cells of the liver become inflamed and die. These are replaced with scar tissue, leading to cirrhosis of the liver, which eventually results in death if untreated.]