Periodic Reporting for period 2 - MORTAL (Understanding mortality: Biosocial determinants across cohorts, time and place)
Reporting period: 2022-12-01 to 2024-05-31
The health and longevity of a population is a key barometer of overall welfare, reflecting the cumulative effects of the broader social, economic, and environmental conditions in which people live. How long we and our loved ones live should be one of the most important questions for society. Recently, life expectancy improvements in the US, UK, and some parts of Europe appear to have stalled after decades of improvement. The COVID-19 pandemic added another huge mortality shock to these pre-existing trends. The MORTAL project seeks to understand why these mortality trends seem to be moving in the wrong direction in many countries. The current research is dominated by a U.S. perspective, yet it is unclear whether the same mechanisms and trends exist in Europe. A clear picture of the drivers of international mortality trends requires an ambitious interdisciplinary effort to combine both theory and data, bringing together diverse expertise (demography, biology, epidemiology, genetics, sociology, economics).
MORTAL combines a biosocial approach with demographic theory to understand the underlying drivers of population mortality. The project aims to answer several important questions:
• When and how are we dying? How is this changing over time and countries?
• What are the most important social and economic changes in people’s life trajectories over the last several decades, and how have these changes impacted mortality?
• How have biological risks changed across generations, including exposure to obesity, infections, smoking, and environmental exposures? How can we use emerging biological signatures including epigenetics and the microbiome to look back in time at early life exposures and predict future trends?
• How will changes in biological and social risk across cohorts affect mortality going forward in Europe and beyond?
Building a model from cells to society, MORTAL will integrate knowledge across disciplines to answer the vital question: as populations, how long do we live, and why?
MORTAL combines a biosocial approach with demographic theory to understand the underlying drivers of population mortality. The project aims to answer several important questions:
• When and how are we dying? How is this changing over time and countries?
• What are the most important social and economic changes in people’s life trajectories over the last several decades, and how have these changes impacted mortality?
• How have biological risks changed across generations, including exposure to obesity, infections, smoking, and environmental exposures? How can we use emerging biological signatures including epigenetics and the microbiome to look back in time at early life exposures and predict future trends?
• How will changes in biological and social risk across cohorts affect mortality going forward in Europe and beyond?
Building a model from cells to society, MORTAL will integrate knowledge across disciplines to answer the vital question: as populations, how long do we live, and why?
The MORTAL project thus far has worked to build up our basic knowledge of mortality trends in the past few decades. We published several high-impact papers quantifying the mortality impact of the COVID-19 pandemic in Europe and other high-income countries. We identified dramatic losses in life expectancy in 2020 due to the COVID-19 pandemic, the magnitude of which had not been seen in many countries since World War II. While 2021 began as more hopeful due to the vaccine roll-out, new variants meant that there were many more SARS-CoV-2 infections and deaths in some countries, while some countries (especially with high vaccination rates) bounced back from their 2020 losses with life expectancy improvements. We are currently working on taking stock of the impact of COVID-19 on mortality trends through 2023 and thinking about how its aftershocks will impact trajectories going forward.
We have also documented trends in so-called “deaths of despair” due to alcohol, drugs, and suicide the UK, US, and Canada. We found that drug-related mortality in the US is dramatically higher than in other countries, except for Scotland, which has seen very high levels of drug-related mortality in recent years, but not necessarily due to opioids. We also looked at whether the troubling trends in mid-age mortality in the US are extending to other countries. We found that the UK is also seeing increasing mortality at younger and middle-ages and an overall worsening relative to the rest of Europe. Slowing improvements in cardiovascular disease mortality seem to be particularly important. We are currently expanding this work by decomposing changes in life expectancy between the UK and other European countries over the last twenty years by cause of death to better understand the causes of death and age groups responsible for this mortality divergence.
Two papers have directly compared the health of adults in the UK to the US using a variety physical health and biological measures. We found that even starting in early mid-life, adults in the US are generally in worse health than their counterparts in the UK, especially for cardiometabolic measures such as obesity, blood pressure, diabetes, and cholesterol. US adults also had wider socioeconomic inequalities in midlife health. Since mortality is the end of a long process, we are also looking at whether younger generations are showing signs of being less healthy at the same ages compared to previous generations. This analysis is challenging because it requires comparable measurements of health or biological risk across many years of surveys and cohorts. Overall, there is some evidence that younger generations in the US, UK, and parts of Europe may be seeing a “generational health drift” whereby health status is no longer steadily improving across generations and may even be getting worse.
We have also documented trends in so-called “deaths of despair” due to alcohol, drugs, and suicide the UK, US, and Canada. We found that drug-related mortality in the US is dramatically higher than in other countries, except for Scotland, which has seen very high levels of drug-related mortality in recent years, but not necessarily due to opioids. We also looked at whether the troubling trends in mid-age mortality in the US are extending to other countries. We found that the UK is also seeing increasing mortality at younger and middle-ages and an overall worsening relative to the rest of Europe. Slowing improvements in cardiovascular disease mortality seem to be particularly important. We are currently expanding this work by decomposing changes in life expectancy between the UK and other European countries over the last twenty years by cause of death to better understand the causes of death and age groups responsible for this mortality divergence.
Two papers have directly compared the health of adults in the UK to the US using a variety physical health and biological measures. We found that even starting in early mid-life, adults in the US are generally in worse health than their counterparts in the UK, especially for cardiometabolic measures such as obesity, blood pressure, diabetes, and cholesterol. US adults also had wider socioeconomic inequalities in midlife health. Since mortality is the end of a long process, we are also looking at whether younger generations are showing signs of being less healthy at the same ages compared to previous generations. This analysis is challenging because it requires comparable measurements of health or biological risk across many years of surveys and cohorts. Overall, there is some evidence that younger generations in the US, UK, and parts of Europe may be seeing a “generational health drift” whereby health status is no longer steadily improving across generations and may even be getting worse.
While existing research on stalling life expectancy is dominated by a US perspective, our work has expanded this deeper examination to the UK and other countries in Europe. This comparative lens is desperately needed to identify specific mechanisms driving mortality changes and test theories specific to the US context that have largely ignored questions of generalizability to other countries. So far, we have identified some similarities with mid-life mortality slowdowns in the UK, but without noticeable increases in “deaths of despair,” which have driven the narrative in the US. We think this points to a need for deeper investigation into slowing improvements in cardiovascular disease and other causes of death that have complex social and biological causes. In the second half of the project, we will continue to describe how the health of cohorts has changed over time, including through measurement of state-of-the-art biological measures such as epigenetic clocks and epigenetic markers of inflammation. We will examine different patterns of the obesity epidemic across countries and cohorts and how this may be contributing to slowdowns in cardiovascular disease improvements across countries. Following recent developments, we will also explore the potential implications of new GLP-1 agonist drugs for treating diabetes and obesity at the population level and its potential impact on future life expectancy. Finally, we will also continue to monitor the longer-term impacts of the COVID-19 pandemic on population mortality, including how the social and biological scars of the pandemic may impact generations to come. Ultimately, we will arrive at a better understanding of what has happened to population mortality in recent decades and where it might be going in the future.