Diverging Pre-Pandemic Mortality Trends: Age-Specific and Cause-Specific Patterns Across High-Income Countries

Background

Mortality rates have declined across most high-income countries for decades, but recent evidence suggests a slowdown in improvements or a shift to increasing mortality, particularly among working-age populations. The international distribution and drivers of these trends remain incompletely understood.

Methods

Mortality trends during 2012–2019 were analysed using all-cause and cause-specific data from 30 countries. Trends were estimated via linear regression. K-means clustering with Dynamic Time Warping identified countries and ICD-10 chapters with similar temporal trajectories.

Results

Trends varied substantially by nation. While Japan, Switzerland, and the Republic of Korea maintained consistent declines in all-cause mortality rates, increases were concentrated in the United States, Canada, and the United Kingdom, most prominently in persons aged 30–59 years. However, cause-specific analysis showed that rising mortality was not confined to these countries: most countries exhibited increases in at least one ICD-10 chapter, with several European countries showing increases across multiple chapters. Across countries, a small set of causes recurred among increasing trends, including external causes (self-harm, drug poisoning) at younger ages and chronic conditions (cardiovascular and liver diseases, specific cancers) in mid-life. Notably, ill-defined causes of death consistently appeared among the increasing causes across countries and age groups.

Conclusions

Mortality increases in the 2010s were geographically more widespread than previously recognized. The recurrent rise in mortality from ill-defined causes suggests that an important component of mortality change remains poorly characterized. These findings indicate that stalled health progress is a systemic challenge across many high-income societies.

Key Messages

• This study investigated the distribution and drivers of all-cause and cause-specific mortality trends within 30 countries between 2012 and 2019.

• While all-cause mortality increases were most acute in the United Kingdom and North America, cause-specific increases were widespread, with several continental European countries showing rises in multiple causes, including injuries, chronic diseases, and ill-defined conditions.

• The widespread rise of these diverse mortality drivers, including poorly understood “ill-defined” causes, indicates that stalled health progress is a systemic challenge requiring a unified public health response across high-income societies.