9. Lung Cancer
Lung cancer still remains to be a leading affliction, despite dropping cigarette popularity. Cigarette smoke contains many harmful carcinogens. These carcinogens increase the risk of contracting lung cancer through direct and indirect smoke. It is one of the most difficult forms of the disease to treat. Cancer originating in the lungs often spreads to other areas of the body. This in turn causes complications in hormonal function, blood cells and other vital systems. It is the leading cause of death among cancer sufferers. Partly due to the widespread effect it has on many areas of the body.