The influence of state minimum wage increases on health and behavior

Low and minimum wage work, prevalent in the United States, is a key driver of both income inequality and income-driven health disparities. Cities and states have increasingly moved to adopt higher minimum wages with the goal of closing the income gap and improving the economic well-being of their residents. Over the last decade, academics and policymakers alike have been interested in the influence of higher wage policies on health and behavior. To date the emerging evidence has been mixed and varies depending on the populations or outcomes under study. Few studies have evaluated the longitudinal relation between higher minimum wages and health or changes in behavior. Moreover, no prior study has explored whether this relation is modified by individual economic circumstances. We used the 1999 to 2017 biannual waves of the Panel Study of Income Dynamics to examine the association between minimum wage and health (obesity, hypertension, fair or poor self-reported health, and moderate psychological distress) and behavior (smoking, drinking, and physical activity) in working-age adults, both employed and unemployed. We used a difference-in-difference-in-differences model using modified Poisson regression to evaluate the association between a $1 increase in minimum wage (current and 2-year lagged) among adults with a high school education or less in the full sample and across racial/ethnic and gender strata. We also used a difference-in-differences regression restricted to those with a high school education or less to determine whether employment instability, as measured by prior-year weeks of unemployment and years of tenure the current employer, modified the influence of minimum wage on obesity and moderate psychological distress. These evaluations of potential effect measure modification were conducted in the full sample and stratified by gender. All models were adjusted for a full set of individual and state-level covariates. We also used state and year fixed effects and cluster robust standard errors to account for within state correlations. No association between minimum wage increases and health or health behavior was observed in the overall sample of working-age adults, employed and unemployed. Subgroup models suggested a marginal reduction in obesity risk (RR = 0.82, 95% CI = 1.03, 1.50) and a marginal increase in daily cigarette consumption (RR = 1.10, 95% CI = 1.01, 1.19) in non-Hispanic White men. Higher obesity risk was found in non-Hispanic White women (RR = 1.35, 95% CI = 1.12, 1.64) associated with 2-year lagged minimum wage. Both higher current (RR = 0.73, 95% CI = 0.54, 1.00) and 2-year lagged minimum wage (RR = 0.75, 95% CI = 0.56, 1.00) were also marginally associated with a reduced risk of moderate psychological distress in non-Hispanic White women. Higher current (RR = 1.19, 95% CI 1.02, 1.40) minimum wage was associated with an increased risk of fair or poor self-reported health in women of color. Estimates were robust to restriction to workers employed hourly at baseline. We also found imprecise but suggestive evidence that prior-year unemployment, but not duration of employment, may modify the relation between minimum wage, obesity, and moderate psychological distress with the greatest risk in those exposed to both high minimum wages and greater unemployment. While no relation was observed between minimum wage and health or behaviors overall, these results are suggestive of potential heterogeneity across race/ethnicity and gender strata. Our findings with respect to modification by employment instability highlight the importance of considering the economic circumstances of individuals when evaluating the relation between social and income policies, such as the minimum wage, and health.