Socioeconomic Inequalities in Premature Cancer Mortality Among U.S. Counties During 1999 to 2018.

BACKGROUND

This study investigated socioeconomic inequalities in premature cancer mortality by cancer types, and evaluated the associations between socioeconomic status (SES) and premature cancer mortality by cancer types.

METHODS

Using multiple databases, cancer mortality was linked to SES and other county characteristics. The outcome measure was cancer mortality among adults ages 25-64 years in 3,028 U.S. counties, from 1999 to 2018. Socioeconomic inequalities in mortality were calculated as a concentration index (CI) by income (annual median household income), educational attainment (% with bachelor's degree or higher), and unemployment rate. A hierarchical linear mixed model and dominance analyses were used to investigate SES associated with county-level mortality. The analyses were also conducted by cancer types.

RESULTS

CIs of SES factors varied by cancer types. Low-SES counties showed increasing trends in mortality, while high-SES counties showed decreasing trends. Socioeconomic inequalities in mortality among high-SES counties were larger than those among low-SES counties. SES explained 25.73% of the mortality. County-level cancer mortality was associated with income, educational attainment, and unemployment rate, at -0.24 [95% (CI): -0.36 to -0.12], -0.68 (95% CI: -0.87 to -0.50), and 1.50 (95% CI: 0.92-2.07) deaths per 100,000 population with one-unit SES factors increase, respectively, after controlling for health care environment and population health.

CONCLUSIONS

SES acts as a key driver of premature cancer mortality, and socioeconomic inequalities differ by cancer types.

IMPACT

Focused efforts that target socioeconomic drivers of mortalities and inequalities are warranted for designing cancer-prevention implementation strategies and control programs and policies for socioeconomically underprivileged groups.