Early Exposure to County Income Mobility and Adult Individual Health in the United States

Despite substantial research, drivers of the widening gap in life expectancy between rich and poor in the U.S. -- the so-called longevity gap -- remain unknown. Recent research has suggested that contextual income mobility (e.g., county-level socioeconomic mobility) may play an essential role in explaining the longevity gap. Previous studies -- based mostly on aggregate and cross-sectional individual data -- show an association between county income mobility and county mortality and individual's health. However, inferring individual effects from aggregate (county-level) data can be problematic (i.e., ecological fallacy), and measuring exposure to income mobility using the county where respondents currently live or die, might overlook the selection process associated with residential mobility. This paper aims to extend previous research by estimating the effect of average exposure to mobility regimes during childhood and adolescence on adult health using longitudinal data and accounting for selection into counties over time (i.e., residential mobility). We use both the National Longitudinal Survey of Youth 1997 (NLSY97) and the Panel Study of Income Dynamics (PSID) with geocoded data to assess the link between county-level income mobility (Chetty's estimates), behaviors (smoking) and health conditions and status (self-reported health, BMI, depressive symptoms). Furthermore, we use cohorts optimally match Chetty's estimates of income mobility in the U.S. (1980-1982) and account for selection and time-varying confounders using marginal structural models (MSM). Overall, we provide a more precise test of the hypothesis that childhood exposure to income mobility regimes may determine health status through behavior (i.e., smoking) later in life and contribute to longevity gaps.