Investigating associations between long-term poverty exposure and premature mortality: evidence from the National Longitudinal Survey of Youth 1979 prospective cohort.

BACKGROUND: Living in poverty increases the risk for mortality. Existing research that examines life course poverty typically relies on measures separated by decades of time. Here, we aimed to estimate the association of 20-year cumulative poverty exposure from emerging adulthood through to established adulthood with premature mortality assessed over the following 15 years. METHODS: We included National Longitudinal Survey of Youth 1979 study participants with three or more family income measures between 1985 and 2004. Participants were, on average, aged 23 years at the start and aged 42 years at the end of this period. Follow-up for premature mortality began in 2004 and ended in 2019, at which time participants were aged 53-62 years. We defined cumulative poverty by the proportion of family size-adjusted income measures less than 200% of the Federal Poverty Level: never in poverty, sometimes in poverty (>0 and less than a third of measures), often in poverty (a third or more but not all measures), and always in poverty. Primary analyses used confounder-adjusted Cox proportional hazards regression models. Our outcome was mortality between 2004 and 2019. FINDINGS: Our sample included 5653 participants, with 1484 (26·2%) never in poverty, 1867 (33·0%) sometimes in poverty, 1852 (32·8%) often in poverty, and 450 (8·0%) always in poverty. 363 (6·4%) participants were reported deceased over follow-up. Compared with participants never in poverty, those sometimes, often, and always in poverty had 1·10 (95% CI 0·79-1·53), 1·53 (1·09-2·14), and 2·53 (1·61-3·96) times higher rates of premature mortality, respectively. INTERPRETATION: Greater cumulative exposure to poverty across emerging and established adulthood is associated with a greater risk for premature mortality. To inform public health action and policy, future research should evaluate the effects of providing support to individuals who are experiencing financial hardships during these important life stages on health and longevity. FUNDING: National Institute of Health's National Institute on Aging.