This post discusses data for 2019, the year before the pandemic started.
Once global data for the period during the pandemic becomes available via the WHO and IHME, you find it in our entry on the causes of death.
To make progress towards a healthier world we need to have a good understanding of what health problems we face today. What do people die from?
This visualization gives us the answer. This type of visualization is called a ‘tree map’. The size of the entire visualization represents the total number of deaths in 2019: that’s 55 million deaths. Each rectangle within it represents one cause of death: its size is proportional to the share of deaths from that particular cause. For example, 18% of global deaths in 2019 were from cancers; the rectangle representing cancers therefore corresponds to 18% of the total area. This way we can quickly see which causes kill many people, and which kill few.
The chart does not show the current situation. It shows the data for the year before the pandemic. During the pandemic the number and causes of deaths have changed. For 2020 it is estimated that 5.7 million people died from COVID and the current 2021 death toll – before the year is even over – is estimated to be 11.5 million.1 Other causes of death declined during the pandemic. We would expect, for example, that traffic deaths would decline when restrictions were in place and travel was reduced.
What the pre-pandemic data does provide is a perspective for where global health could get back to once the pandemic retreats.
In everyday language we sometimes say that a person died of ‘old age’ or that they ‘died of natural causes’. But there is always an underlying cause that stopped their body from functioning. It is these specific causes that are visualized in this chart. When the cause of death is not recorded then researchers rely on models to estimate the cause.
Epidemiologists group the causes of deaths into three large categories:
- Shown in blue on the left are non-communicable diseases; diseases which cannot be passed from person to person. The two most common causes of death fall into this group: cancers kill 18% of people and cardiovascular diseases – such as stroke and ischemic heart disease – are responsible for one-in-three deaths in the world.
- Shown in red are communicable or infectious diseases; diseases that are caused by a pathogen which can be passed from person to person.
This is where we have made most progress. In the past most people died from infectious diseases. Still today, it’s likely the group that we can make the most progress against in the coming years. Very few people die from these diseases in rich countries. Poorer countries are rapidly developing in this direction. Many of these deaths can be prevented with modern technologies, such as vaccines, antibiotics, and public health infrastructure like sanitation and clean water.
Maternal deaths, the deaths of newborns, and deaths from nutritional deficiencies are often closely linked to infectious diseases. Most of these are preventable. You find them right underneath in the visualization.
- In green you see injuries. This is a very wide category which includes accidents – such as car crashes and falls from stairs or ladders – as well as intentional injuries like homicides, war deaths, and suicides.
What the world dies from is not what is reflected in the media. Some major causes of deaths receive very little attention. Very rare tragedies draw outsized attention – have a look at the bracket in the bottom right, there you see the small rectangle that refers to the deaths due to terrorism.
Violence is, fortunately, a relatively rare cause of death. While it receives a lot of media attention, more people die from diarrheal disease than from all forms of violence put together.2
This is the perspective we need if we want to contribute to progress against the world’s largest problems. We need a good sense of the relative importance of different causes of death and we need to focus our efforts on the biggest rectangles in this visualization. If we don’t look at the data it is easy to miss that preventing deaths from diarrhea would save more lives than bringing an end to all violence. The former should be much easier to achieve, too. We already know how to do it.