In 2021, the top 10 causes of death accounted for 39 million deaths, or 57% of the total 68 million deaths worldwide. The top global causes of death can be broadly categorized into cardiovascular (such as ischaemic heart disease and stroke) and respiratory (including COVID-19, chronic obstructive pulmonary disease, and lower respiratory infections) issues. COVID-19 emerged as the second leading cause of death globally, highlighting the impact of the ongoing pandemic on mortality rates.
Causes of death can be grouped into three main categories: communicable (infectious and parasitic diseases, maternal, perinatal, and nutritional conditions), noncommunicable (chronic diseases), and injuries. At a global level, 7 of the 10 leading causes of death in 2021 were noncommunicable diseases, accounting for 38% of all deaths or 68% of the top 10 causes.
The leading cause of death globally in 2021 was ischaemic heart disease, responsible for 13% of total deaths. COVID-19, as a newly emerged cause of death, directly accounted for 8.8 million deaths in 2021. Other leading causes of death included stroke, chronic obstructive pulmonary disease, lower respiratory infections, trachea, bronchus and lung cancers, Alzheimer’s disease and other forms of dementia, and diabetes.
Interestingly, diseases such as HIV and AIDS and diarrhoeal diseases, which were among the top 10 causes of death in 2000, have seen significant decreases in mortality rates. On the other hand, kidney diseases have risen in the rankings, showcasing the changing landscape of global health challenges.
When looking at causes of death by income group, low-income countries are more likely to see deaths from communicable diseases, while high-income countries face increasing mortality rates due to population aging. COVID-19 has had a significant impact on mortality rates across all income groups, with lower-middle-income countries seeing the highest number of deaths from the virus in 2021.
Understanding the reasons people die is crucial for improving overall health outcomes and directing resources where they are most needed. Mortality data helps assess the effectiveness of health systems and guides resource allocation in various sectors. Investing in civil registration and vital statistics systems is essential for accurate data collection and analysis, especially in low-income countries where data fragmentation remains a challenge.
The World Health Organization plays a key role in developing standards and best practices for data collection and analysis through the International Classification of Diseases (ICD-11). High-quality data on deaths and causes of death, along with data on disability, is essential for improving health outcomes and reducing mortality rates worldwide.
In conclusion, understanding the leading causes of death globally and by income group is essential for addressing health challenges and improving overall well-being. By focusing on data collection, analysis, and resource allocation, we can work towards reducing mortality rates and improving health outcomes for all.