In 2023, close to 13 million people died across OECD countries, with an average rate of 861 deaths per 100 000 population (Figure 3.2). This reflects a slightly lower mortality rate than 2021, during the pandemic. Diseases of the circulatory system and cancer are the two leading causes of death, accounting for almost half of all deaths in OECD countries. The epidemiological transition from communicable to non-communicable diseases, which has already taken place in high-income countries, is ongoing in many middle‑income countries. Across 36 OECD countries in 2023, over 3 million deaths among people aged under 75 years could have been avoided (see section on “Avoidable mortality”). For example, circulatory conditions caused almost one in three deaths in the population, mainly due to heart attacks and strokes – both largely avoidable by adequate management of clinical and behavioural risk factors (OECD, forthcoming[1]).
Cancer accounted for one in five deaths across OECD countries – particularly cancer of the lungs, colon and rectum, pancreas, breast, and prostate. Respiratory diseases accounted for 9% of deaths, mainly due to chronic obstructive pulmonary disease (COPD) (3%) and pneumonia (3%). COPD and lung cancer are associated with preventable risk factors – notably smoking, but also occupational exposure to dust, fumes and chemicals, and air pollution (see Chapter 4 “Non-medical determinants and risk factors”). COVID‑19 accounts for 5% of total deaths, explained by the persistent transmission of the virus and its effect on older adults and people with underlying conditions, and partially by reporting delays.
External causes were responsible for 7% of deaths across OECD countries – notably accidents (including traffic accidents, falls and poisoning), which accounted for almost 6% of all deaths, and suicides, which accounted for 1.2% of all deaths. Falls are particularly important for ageing populations, as some older adults have physical vulnerabilities and lack the support mechanism to call on medical services quickly (Xu, Ou and Li, 2022[2]).
Looking at other specific causes, conditions of the nervous system accounted for 5% of all deaths, including Alzheimer’s disease (2.3% of all deaths). Diabetes represented 3% of all deaths across OECD countries and is an important risk factor for cardiovascular conditions (OECD, forthcoming[1]).
The main causes of death differ between socio‑economic groups, with social disparities generally larger for the most avoidable diseases. For example, people with the lowest level of education are more likely to smoke in most OECD countries, increasing the risk of developing cancers and diseases of the respiratory system (OECD, 2019[3]).
Across OECD countries, all-cause age‑standardised mortality rates in 2023 ranged from under 700 deaths per 100 000 in Japan, Switzerland, Luxembourg, Spain and Australia, to over 1 400 deaths per 100 000 in Colombia (Figure 3.3). On average, the total mortality rate across OECD countries was 861 per 100 000 in 2023, similar to the 2019 pre‑pandemic mortality rate (830 per 100 000). Diseases of the circulatory system are the leading cause of death for 27 OECD countries, followed by neoplasms (mainly cancers). Neoplasms are the leading cause of death in ten OECD countries: Japan, Spain, Australia, Korea, France, Israel, Canada, the Netherlands, Denmark and the United Kingdom (Figure 3.3). Among OECD accession countries, mortality rates were highest in Brazil (1 413 per 100 000 population) and Bulgaria (1 452 per 100 000).
