Causes of death and disability can be grouped into three large categories: communicable (infectious diseases, along with maternal, perinatal and nutritional conditions), noncommunicable (chronic diseases) and injuries.
Monitoring the yearly number of deaths helps to address their causes and adapt health systems to react effectively, triggering responses of multiple sectors: from transportation (in addressing road traffic accidents) to food and agriculture (in tackling the rise in diabetes prevalence) and mental health support (in early detection of mental health conditions).
Understanding the reasons why people die, can help comprehend the ways people live to improve health services and reduce preventable deaths in every country, responding effectively to changing epidemiological circumstances.
Summary findings
Noncommunicable diseases have become more prominent with Alzheimer’s disease and diabetes entering whereas communicable diseases are on the decline with HIV dropping out of the top 10.
The world’s biggest killer is ischaemic heart disease, responsible for 13% of the world’s total deaths. Since 2000, the largest increase in deaths has been for this disease, rising by 2.7 million to 9.0 million deaths in 2021.
As a newly emerged cause of deaths, COVID-19 was directly responsible for 8.7 million deaths in 2021.
Lower respiratory infections remained the world’s most deadly communicable disease other than COVID-19, ranked as the fifth leading cause of death in 2021, although the total number of deaths from lower respiratory infections has decreased.
WHO methods and data sources for country-level causes of death 2000-2021
