Smoking is a quite significant health risk, and so avoiding smoking is one of the most important things you can do for your health. Smoking adversely affect the cardiovascular and respiratory systems and increases your risk of most cancers. Maternal smoking also harms foetuses in utero and can cause still and premature births and other problems for the babies of parents who smoke. Smoking also damages your eyes and teeth and can increase your risk for type II diabetes.
According to the Centers for Disease Control and Prevention, cigarette smoking causes approximately 480,000 deaths a year in the United States and is the single leading cause of preventable deaths. Smoking reduces your life expectancy by more than ten years.
After you quit smoking, your risk of diseases and early death slowly returns to the levels found in nonsmokers. Thus not smoking or quitting smoking are among the most import things you can do to improve your health.
The health risks of smoking are very real and are definitely an order of importance. There have been innumerable studies done on the effects of smoking and almost all of these have negative results to show. The nicotine used to create cigarettes was found to have an addictive quality caused by stimulating the dopamine center of the brain. While addiction is bad enough by itself the consequences to one's health only make it worse. Smoking is currently the leading cause of lung cancer and is an incredibly dangerous carcinogen. Although one or two smokes may not hurt, getting hooked on smoking and smoking frequently have very clear and dangerous consequences.