Spatially Continuous Maps of Disease Risk: An Analysis of Mortality Disparities in the United States

In the U.S., race and education have proven to be critical determinants of health outcomes inequalities, influenced by both location and time. Lung cancer (primarily linked to smoking), along with drug overdoses, alcohol poisoning, and suicide, emerge as important contributors to mortality risk. The purpose of this study is to enhance the understanding of geographic disparities in mortality related to lung cancer and external causes of death in the U.S. This study focuses on a finer geographic scale while examining the components of variation in mortality rates, stratifying by both education and race.

This study used an aggregated spatial model and Bayesian inference to create continuous maps of risk. The study analyzes mortality counts from 1999 to 2015. This approach not only allows one to analyze and combine data sources at different spatial resolutions in a shorter time, but also facilitates standardized comparisons across age, sex, education, and spatial location.

Education emerged as the primary source of variation in both types of mortality, with growing disparities since 1999. Spatially, mortality risk varies more among the less educated and less among the more educated. Lung cancer rates have declined for the most educated but stayed steady for the less educated, while external causes of death rates rose for the less educated but remain unchanged for the more educated ones. Racial differences are significant for external causes of death but minimal for lung cancer.

These findings highlight the need to go beyond education as a simple predictor variable in mortality studies, while also accounting for the differences in the nature of spatial variation. While the impact of education on mortality rates is unsurprising, the fact that Black Americans on average encounter inferior socioeconomic conditions compared to White Americans, may explain why this group is usually recognized at higher risk. This investigation suggests that addressing racial disparities in education levels could help to reduce tobacco-related mortality discrepancies effectively.