A recent study published in the Proceedings of the National Academy of Sciences analyzed changes in mortality in the United States (US) from 1979 to 2019, with additional data extending to 2023. The research examined how cardiovascular deaths, external causes, and generational health patterns influence longevity, providing insights into the stagnation of US life expectancy.
Life Expectancy Trends
The US has experienced a significant slowdown in life expectancy gains, with an improvement of just 0.26 years between 2010 and 2019. This starkly contrasts with an average gain of 1.78 years per decade over the preceding five decades. While this slowdown is also observed in other high-income countries, the US trend is notably more pronounced.
Previous studies attributed this stagnation to suicides, alcohol-related deaths, drug overdoses, and a plateau in the decline of cardiovascular disease (CVD) deaths. The current study, however, placed a strong emphasis on understanding mortality trends by birth cohort.
Research Methodology
Researchers utilized Lexis diagrams and regression models to meticulously analyze mortality data. The data was sourced by year, age, and cause of death from the National Vital Statistics System and the Human Mortality Database. The comprehensive study included cohorts born between the 1890s and the 1980s, evaluating all-cause mortality, cancer deaths, CVD mortality, and deaths from external causes.
Key Cohort Findings
1950s Birth Cohorts
Cohorts born in the 1950s displayed higher overall mortality rates compared to preceding generations at nearly all adult ages. Females in these cohorts, in particular, showed elevated cardiovascular disease mortality.
Broad Mortality Deterioration Post-2010
A broad worsening of mortality began around 2010, impacting most adults alive at that time. This deterioration was primarily driven by adverse changes in cardiovascular disease mortality.
Younger Cohorts (1970s-1980s)
Alarming mortality increases were observed for individuals aged 30 to 45 years in the 2010s, particularly among younger cohorts born between the 1970s and 1980s.
Cancer Mortality Patterns
While overall cancer mortality improved for many cohorts, the 1950-1959 cohorts exhibited higher or stagnant mortality declines, especially among females. Critically, cohorts born between 1970 and 1985 also showed adverse cancer patterns at younger adult ages.
External Causes of Death
Deaths from external causes, which encompass drug overdoses, suicides, traffic accidents, and homicides, declined from 1980 to 1995 but subsequently increased. The 1950-1959 cohorts showed higher rates of these deaths at ages 40-69, with progressively higher rates noted in cohorts born between 1970 and 1989.
Drug overdose deaths rose sharply from the late 1990s. Suicide mortality among females worsened significantly from 2000, impacting all cohorts by 2010. Furthermore, significant increases in traffic accidents and homicides were observed throughout the 2010s.
Impact of COVID-19 Pandemic
The years affected by the COVID-19 pandemic (2019-2023) introduced further complexities. This period saw an increase in mortality from all causes, external causes, cancer, and cardiovascular disease across most cohorts. Cardiovascular disease mortality increased from 2019 to 2022 before showing some recovery by 2023. External deaths also increased, while cancer mortality, notably, improved during this challenging period.
Conclusion
The study concludes that the 1950s birth cohort represents a crucial transitional period, shifting from generally improving mortality in earlier cohorts to worsening trends in later ones. The broad mortality deterioration observed around 2010, largely due to cardiovascular disease mortality, reflects a complex and multifaceted crisis.
This suggests that the stagnation of US life expectancy is not attributable to a single cause or mechanism. Instead, it points to a multifaceted problem that may signal a risk of prolonged stagnation or even further declines if current cohort trends persist.