Effects of US state preemption laws on infant mortality.

Studies show that raising the minimum wage in a US state above the federal minimum wage can reduce infant mortality rates in those states. Some states have raised their minimum wage in recent decades, while many others did not, and have prohibited local authorities from doing so by enacting preemption laws. This study investigates how the recent emergence of state preemption laws that remove local authority to raise the minimum wage has affected infant mortality rates. Using county- and state- level data spanning 2001 through 2018, this study models infant mortality rates as a function of minimum wage levels, controlling for confounders. The estimated model, combined with information on the timing, location, and level of preempted minimum wages, is then used to estimate the number of infant deaths that occurred in 2018 that could be attributed to state preemption of local minimum wage increases. In the 9 largest (pop. > 250,000) metro counties most directly affected by state preemption, we estimate that in 2018, 25 infant deaths were attributable to preemption. This equates to a 5.4% reduction in these counties' infant mortality rate. When considering all large metro counties in preemption states, as many as 605 infant deaths could be attributed to preemption. State preemption laws that remove local authority to enact health-promoting legislation, such as minimum wage increases, are a significant threat to population health. The growing tide of these laws, particularly since 2010, may be contributing to recent troubling trends in US life expectancy.