Past research has noted that socioeconomic status is a part of a web of correlations that include wealth, intelligence, education, lifestyle choices, and longevity. Untangling all of that to make definitive pronouncements on what exactly drives the observed variation in human life span has proven challenging. It is a reasonable assumption, based on animal studies, that lifestyle choices and consequent degree of physical fitness are the primary factor determining late life survival, however. Here, researchers take a more subtle approach to data analysis and conclude that socioeconomic and demographic status has very little influence on individual longevity. This is much as we might expect if lifestyle choice related to fitness is the primary influence, as will continue to be the case until the first therapies targeting mechanisms of aging become used far more widely.
Against the backdrop of descriptive, causal, and theoretical work on mortality, the explosion of rich microdata has enabled a new predictive perspective. In this study, we apply this perspective to ask: Can observable sociodemographic characteristics - such as education, income, race, and marital status - predict individual-level lifespan? This question tests the limits of social determinism. If lifespan is highly predictable, it would suggest that one's lifespan is tightly structured by systemic forces ("demography is destiny"). Low predictability would imply that, despite large and well-documented between-group mortality disparities, most lifespan variation remains unexplained by major social or economic factors. This distinction matters for how we think about lifespan inequality: Is mortality governed more by structural inequalities or by stochastic individual variation?
Using U.S. Census data linked to administrative death records, we assess how well early-adulthood social, economic, and demographic characteristics predict individual lifespan in a cohort of men born in 1910 and observed through their deaths between 1975 and 2005 (N = 121,000). Despite large group-level disparities, we find that sociodemographic characteristics measured in early adulthood explain less than two percent of the overall variation in individual lifespan. These findings reaffirm a central demographic regularity: variance in life expectancy between groups is small compared to variation in lifespan within groups. This highlights the fundamentally nondeterministic nature of how structural inequality shapes individual mortality.
Link: https://doi.org/10.1111/padr.70065
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