What is the deadliest disease in the world?

Ask an expert
16 May 2012

Q: What is the deadliest disease in the world?

A: The results of ranking the leading causes of death are subject to the cause categories used. The broader the cause categories used, the more likely they will rank among the top leading causes of death.

According to the estimates in the Causes of death 2008 update, there were 57 million deaths in the world in 2008. The broad category of all "noncommunicable diseases" killed 36 million people; communicable diseases, maternal and perinatal conditions, and nutritional conditions killed 16 million people worldwide; and external causes of injuries killed 5 million people.

The following are the leading causes of death:


No. Cause Estimated number of deaths (in millions) Percent of all deaths
1 Ischaemic heart disease 7.25 12.8
2 Cerebrovascular disease 6.15 10.8
3 Lower respiratory infections 3.46 6.1
4 Chronic obstructive pulmonary disease 3.28 5.8
5 Diarrhoeal diseases 2.46 4.3
6 HIV/AIDS 1.78 3.1
7 Trachea, bronchus, lung cancers 1.39 2.4
8 Tuberculosis 1.34 2.4
9 Diabetes mellitus 1.26 2.2
10 Road traffic accidents 1.21 2.1
11 Hypertensive heart disease 1.15 2.0
12 Prematurity and low birth weight 1.00 1.8

Source: Causes of death 2008 update

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