Unincorporation in counties as a political determinant of health: An exploration of five states.

Local government policies and practices shape the context of the places that can alter a population's life chances through socioeconomic factors, built environments, and healthcare access. County governments, one of the most ubiquitous U.S. political structures, impact health outcomes within their jurisdiction through multiple policy levers and pathways. By identifying which political determinants within counties are associated with variation in life expectancy and premature death, we can better intervene on modifiable factors. One overlooked political determinant from public health studies is the county's responsibility as the primary local government for approximately a third of the U.S. population and 93% of land in unincorporated areas. To conduct an ecological study and assess associations between county population health and county responsibility for unincorporated areas and populations, we created and tested two county indicators of unincorporation. Multilevel multivariable regression results showed that larger proportions of unincorporated land within a county are associated with lower average county life expectancy. More testing of the measurement is needed to understand the relationship between unincorporation, county government, and population health outcomes.