Life expectancy has increased in all OECD countries over the past 50 years, but progress has slowed over the last decade. Furthermore, the COVID‑19 pandemic led to life expectancy falling in most OECD countries in 2020 (see Chapter 2 for an in-depth analysis of the health impact of COVID‑19).

Women live longer than men in all OECD member and partner countries. This gender gap averaged 5.3 years across OECD countries in 2019 – life expectancy at birth for women was 83.6 years, compared with 78.3 years for men (). The gender gap in life expectancy has narrowed by one year since 2000, however, reflecting more rapid gains in life expectancy among men in most countries.

Excess mortality measures whether, and if so to what extent, the total number of deaths from all causes is over and above what could normally be expected for a given period of time. Here, deaths in 2020 are compared against the average over the previous five years. Excess mortality has been particularly useful in providing a fuller understanding of the impact of COVID‑19 across countries, since it is unaffected by country-specific variations in the recording of COVID‑19‑specific deaths, and accounts for both deaths directly attributable to COVID‑19 and deaths indirectly linked to the virus (Morgan et al., 2020[5]). For example, there may have been more deaths in 2020 than would have normally been expected due to health systems not being able to cope with other conditions. This may be counterbalanced to some extent by potentially fewer fatalities from traffic and workplace accidents, and a reduction in the number of deaths from other infectious diseases.

In 2019, over 11 million people died across OECD countries – equivalent to 770 deaths per 100 000 population (). Diseases of the circulatory system and cancer were the two leading causes of death in most countries. This reflects the epidemiological transition from communicable to non-communicable diseases, which has already taken place in high-income countries and is rapidly occurring in many middle‑income countries (Roth et al., 2018[7]). Across OECD countries in 2019, heart attacks, strokes and other circulatory diseases caused about one in three deaths; one in four deaths were related to cancer. Population ageing largely explains the predominance of deaths from circulatory diseases – with deaths rising steadily from age 50.

Indicators of avoidable mortality offer a general “starting point” to assess the effectiveness of public health and health care systems in reducing deaths from various diseases and injuries. However, further analysis is required to assess more precisely different causes of potentially avoidable deaths and the interventions to reduce them.

Circulatory diseases – notably heart attack and stroke – were the main cause of mortality in most OECD countries in 2019, accounting for almost one in three deaths across the OECD. While mortality rates have declined in most OECD countries over time, population ageing, rising obesity and diabetes rates may hamper further reductions (OECD, 2015[11]). Indeed, prior to the COVID‑19 pandemic, slowing improvements in heart disease and stroke were one of the principal causes of a slowdown in life expectancy gains in many countries (Raleigh, 2019[2]). Furthermore, COVID‑19 may indirectly contribute to more deaths from circulatory diseases, owing to disruptions to acute, primary and preventive care.

Cancer was the second leading cause of death in OECD countries after circulatory diseases, accounting for 24% of all deaths in 2019. Leading causes of cancer-related mortality included lung cancer (21%), colorectal cancer (11%), breast cancer (15% among women) and prostate cancer (10% among men). These four represent 44% of all cancers diagnosed in OECD countries. Mortality rates from cancer have fallen in all OECD countries since 2000, although on average the decline has been more modest than for circulatory diseases.

Chronic conditions such as cancer, chronic respiratory problems and diabetes are not only the leading causes of death across OECD countries. They also represent a major disability burden among the living. Many chronic conditions are preventable, by modifying major risk factors such as smoking, alcohol use, obesity and physical inactivity. The COVID‑19 pandemic has also underscored the impact of chronic conditions on health outcomes from other diseases. Chronic conditions representing a high burden of morbidity across OECD countries – including diabetes, COPD, cardiovascular conditions and cancer – have also been associated with a higher risk of developing more serious COVID‑19 illness, hospitalisation and death.

Inadequate living conditions, extreme poverty and socio‑economic factors affect the health of mothers and newborns. However, effective health systems can greatly limit the number of infant deaths, particularly by addressing life‑threatening issues during the neonatal period. Around two‑thirds of deaths during the first year of life occur before an infant reaches 28 days (neonatal mortality), primarily from congenital anomalies, prematurity and other conditions arising during pregnancy. For deaths beyond these first critical weeks (post-neonatal mortality), there tends to be a greater range of causes – the most common being sudden infant death syndrome, birth defects, infections and accidents. Child mortality rates – referring to deaths among children before the age of five – have fallen dramatically in recent decades, with the majority of deaths among children occurring during infancy.

Good mental health is vital for people to be able to lead healthy, productive lives (OECD, 2021[19]). During the COVID‑19 crisis, when OECD populations experienced significant disruption to the way they live, learn and work, substantial impacts on mental health have been observed (see Chapter 2 for further analysis of the mental health impact of COVID‑19). In March and April 2020, recorded levels of anxiety and depression in the general population were higher in almost all countries compared to previous years (, ). These increases in mental distress have not been consistent across the health crisis, or across all population groups. In countries such as Canada, France, the Netherlands and the United Kingdom, where mental health status was tracked throughout the pandemic it improved in the period June to September 2020; this coincided with lower case rates of COVID‑19 and fewer infection containment measures (OECD, 2021[20]). People who were unemployed or experiencing financial difficulties reported higher rates of anxiety and depression than the general population during the COVID‑19 crisis, which is a trend that pre‑dates the crisis but seemed to have accelerated in some countries (OECD, 2021[20]). Young people’s mental health was also hit particularly hard during the pandemic, with prevalence of symptoms of anxiety and depression rising dramatically, especially in late 2020 and early 2021 (OECD, 2021[21]).

How individuals assess their own health provides a holistic overview of both physical and mental health. Adding such a perspective on quality of life complements life expectancy and mortality indicators that only measure survival. Further, despite its subjective nature, self-rated health has proved to be a good predictor of future health care needs and mortality (Palladino et al., 2016[24]).