1. Coronary Artery Disease (Ischemic Heart Disease)
The deadliest disease in the world is coronary artery disease (CAD). CAD, also called ischemic heart disease, occurs when the blood vessels that supply blood to the heart become narrowed. The World Health Organization (WHO) estimates that about 7.4 million people died of ischemic heart disease in 2012. That was about 13.2 percent of all deaths.
A stroke is when an artery in the brain is blocked or leaks. Oxygen-deprived brain cells begin to die within minutes.
3. Chronic Obstructive Pulmonary Disease (COPD)
chronic, progressive lung disease that makes it hard to breathe. Chronic bronchitis and emphysema are types of COPD.
About 3.1 million deaths were attributed to COPD in 2012, according to WHO. That represents about 5.6 percent of deaths, a rate that has held steady since 2000. In 2004, about 64 million people around the world were living with COPD.
4. Lower Respiratory Infections
WHO estimates that lower respiratory infections caused about 3.1 million, or 5.5 percent of deaths in 2012. This group of diseases includes pneumonia, bronchitis, and influenza.
Flu season lasts from December through February in the Northern Hemisphere and from June through August in the Southern Hemisphere. The risk is year round in tropical regions.
5. Trachea, Bronchus, and Lung Cancers
Trachea, bronchus, and lung cancer are all respiratory cancers. The main causes of this type of cancer are smoking, second-hand smoke, and environmental toxins.
WHO estimates that in 2012, 1.6 million people died from trachea, bronchus, and lung cancers. These cancers represent about 2.9 percent of all deaths globally.