Disparities in wellbeing in the USA by race and ethnicity, age, sex, and location, 2008-21: an analysis using the Human Development Index.

Background: The Human Development Index (HDI)-a composite metric encompassing a population's life expectancy, education, and income-is used widely for assessing and comparing human development and wellbeing at the country level, but does not account for within-country inequality. In this study of the USA, we aimed to adapt the HDI framework to measure the HDI at an individual level to examine disparities in the distribution of wellbeing by race and ethnicity, sex, age, and geographical location.

Methods: We used individual-level data on adults aged 25 years and older from the 2008-21 American Community Survey (ACS) Public Use Microdata Sample. We extracted information on race and ethnicity, age, sex, location (Public Use Microdata Areas), educational attainment, and household income and size. We merged these data with estimated life tables by race and ethnicity, sex, age, location (county), and year, generated using Bayesian small-area estimation models applied to death certificate data from the National Vital Statistics System. For each individual in the ACS, we used these combined data to estimate years of education, household consumption, and expected lifespan; converted each of these three features into an index using a percentile score; and calculated the HDI as the geometric mean of these three indices. Finally, we grouped individuals into yearly HDI deciles.

Findings: Years of education, household consumption, and expected lifespan-and thus the HDI-varied considerably among adults in the USA during the 2008-21 period. For most race and ethnicity and sex groups, the mean HDI increased gradually from 2008 to 2019, then declined in 2020 due to declines in expected lifespan, although there were systematic differences in the distribution of the HDI by race and ethnicity and sex. In the lowest HDI decile, there was over-representation (ie, >10% of the total population of a given race and ethnicity and sex group) of American Indian and Alaska Native (AIAN) males (50% [SE 0·2] in decile, mean annual population in decile 0·37 million [SE 0·002]), Black males (40% [<0·1], 4·67 million [0·006]), AIAN females (23% [0·1], 0·19 million [0·001]), Latino males (21% [<0·1], 3·27 million [0·006]), Black females (14% [<0·1], 1·86 million [0·004]), and Latina females (13% [<0·1], 2·07 million [0·006]). Given differences in total population size, however, White males were the largest population group in the lowest decile (27% [<0·1] of the lowest decile, 5·87 million [0·012]), followed by Black males (22% [<0·1]) and Latino males (15% [<0·1]). There were notable differences in these patterns by age group: for example, for the 25-44 years age group, the lowest HDI decile had even greater over-representation of AIAN males (66% [0·2] in decile, 0·22 million [0·001]) and Black males (46% [<0·1], 2·52 million [0·005]) than the 85 years and older age group (22% [1·1], <0·01 million [<0·001]; and 20% [0·3], 0·03 million [<0·001]). By contrast, the lowest decile had an under-representation of Asian females (2% [<0·1], 0·06 million [<0·001]) in the 25-44 years age group, but an over-representation in the 85 years and older age group (25% [0·3], 0·03 million [<0·001]). The lowest HDI decile for the 25-44 years age group was primarily male (76% [<0·1], 6·44 million [0·009]) whereas for age 85 years and older it was predominantly female (71% [0·1], 0·42 million [0·002]). In the highest HDI decile, shifts in the composition of the population by age were particularly large for White males, who made up 5% (0·1; 0·39 million [0·001]) of this decile in the 25-44 years age group, but 49% (0·2; 0·29 million [0·001]) in the 85 years and older age group. From 2012 to 2021, the proportion of the population living in the lowest HDI decile varied substantially by location, and a disproportionately high share of the population living in locations in much of the southern half of the USA, Appalachia, and Rust Belt states were in the lowest HDI decile.

Interpretation: Substantial disparities in wellbeing exist within the USA and are heavily influenced by race and ethnicity (due to racism), sex, age, and geographical location. These disparities are not immutable, but improvement is not a given, and gains can be fleeting in the face of a crisis such as the COVID-19 pandemic. Sustained action to ensure that everyone has meaningful access to a high-quality education, the means to earn a sufficient income, and the opportunity to live a long and healthy life is needed to reduce these disparities and should focus on the populations and locations that are worst off.

Funding: State of Washington and National Institute on Minority Health and Health Disparities.