Recent studies have shown a direct relationship between decreased bone density and smoking. Because of this decrease in bone density, smokers are at greater risk of osteoporosis, a disease in which bones become brittle and easy to break (health effects of smoking). In addition to the cancers and osteoporosis that can result from smoking, smoking can have a serious impact on cardiovascular health. When you smoke, atherosclerosis occurs, i.e. accumulation of fatty substances, in the arteries. This is the main factor contributing to smoking-related deaths. Smoking also plays a major role in contributing to the development of coronary heart disease, decreases HDL (good cholesterol) levels, increases the risk of developing an aortic aneurysm, stroke, and more. Because of all these risks and more, smoking causes more than 480,000 deaths per year (Why Smoking Is Bad for You