Stark Regional Disparities in US Life Expectancy Trends Revealed in Comprehensive Birth Cohort Analysis
Life expectancy increased steadily in the US West and Northeast across the 20th century, but gains were just minimal in Southern states, according to the findings.
Life expectancy trends across US states show wide disparities by birth cohort, with some states experiencing little or no improvements since 1900, according to a cohort analysis published in JAMA Network Open.1
Theodore Holford, PhD
Courtesy of Yale School of Public Health
Courtesy of Yale School of Public Health
Researchers analyzed 179 million deaths between 1969 and 2020, estimating life expectancy at birth and at age 40 across all US states and Washington, DC, for cohorts born from 1900 to 2000.
In the West and Northeast, cohort life expectancy improved steadily across the 20th century. In contrast, many Southern states showed minimal gains: for women, cohort life expectancy changed less than 3 years from 1900 to 2000; for men, it changed less than 2 years since 1950. Washington, DC, had the lowest life expectancy for the 1900 birth cohort (61.1 years) but had the most dramatic improvement overall, with an increase to 72.8 years for the 2000 cohort.1
Mortality data were modeled using age-period-cohort methods with constrained cubic splines, enabling the research team to account for changes over time while estimating cohort-specific mortality patterns.
First author Theodore R Holford, PhD, Susan Dwight Bliss Professor Emeritus of Biostatistics and Senior Research Scientist in Biostatistics at the Yale School of Public Health and colleagues found the highest life expectancy in 2020 in Hawaii (84.5 years), and the lowest in that year in Arkansas (76.6 years), Alabama (76.4 years), Kentucky (76.4 years), West Virginia (75.9 years ), and Mississippi (75.6 years). States with lower life expectancy also showed less change over time, Holford et al noted, and particularly after 1995. Men showed an increase in life expectancy for each state, although the change was smaller after 1995 for states with the lowest life expectancy in 2020.1
Factors Influencing Degree of Change
The magnitude of change varied considerably. For example, female cohort life expectancy in New York rose by 20 years from the 1900 to 2000 cohorts. In Oklahoma, however, it decreased by 0.7 years over the same period. The reasons for the variations are multiple and overlapping, the authors wrote, and pointed to health behaviors such as cigarette smoking and drug use, environmental conditions, social interactions, vaccination coverage, and access to health care. Holford and team also suggested that infection and other causes of systemic inflammation may have contributed to observed mortality trends. All of these factors, they said, can differentially affect specific causes of death and influence the overall disease burden in each state.1
After age 35, rate-doubling times—a measure of how quickly mortality risk increases with age—varied significantly by state. The highest rate-doubling time was 9.39 years for women in New York and 11.47 years for men in Florida, suggesting slower aging-related mortality increases. In contrast, women in Oklahoma and men in Iowa had the shortest rate-doubling times at 7.96 and 8.95 years, respectively.1
Data on state differences in mortality, which is often used to establish health policy, are typically analyzed in cross-sectional analyses rather than by birth cohorts,2 Holford and colleagues wrote. While the former approach is useful for analysis by age group, each year includes different birth cohorts. Their cohort-based approach allows assessment of the impact of policy changes that affect specific generations, offering additional insight into long-term public health outcomes that are “more reflective of lived experiences of populations,” the researchers said.1
Drivers of Disparities
Holford et al emphasize the impact on disparities in state and regional mortality of differences in public policy, sociodemographics, rurality, and behavioral norms.3 For example, they highlight California's 1995 smoke-free workplace policies, which changed smoking behaviors among 1980s-1990s birth cohorts, improving mortality outcomes. Kentucky, with minimal tobacco control, experienced higher smoking rates and mortality,4,5 patterns mirrored in West Virginia, Oklahoma, Arkansas, Tennessee, Louisiana, Mississippi, and Alabama. Socioeconomically advantaged states showed faster mortality improvements, highlighting how labor, immigration, civil rights, and environmental policies shape population health outcomes.1
Among the study’s limitations, the authors acknowledged that misclassification in mortality data, particularly regarding race and ethnicity, may affect state-specific estimates. Migration patterns could introduce bias if individuals moved from their birth state. Additionally, the model does it fully capture cohort-specific risk factor exposures occurring later in life, according to the study.
"Understanding how mortality patterns vary by birth cohort within each state can inform decision-making around resource allocation and public health interventions," the authors wrote in their discussion. “If addressing geographic health disparities is indeed a nationwide priority, then this study contributes to the necessary data infrastructure for health equity progress," they concluded.1
