In a study reported in JAMA Oncology, Zhang et al found that U.S. counties with greater deprivation as measured by residential racial and economic segregation using the Index of Concentration at the Extremes (ICE) had higher cancer mortality rates vs less deprived counties.
Study Details
The study used county-level sociodemographic data from the 2015–2019 American Community Survey linked with 2015–2019 county-level mortality data for 3,110 counties. Racial and economic segregation measured by ICE was categorized into quintiles (Q), with Q1 representing the most deprived and Q5 representing the most privileged counties.
Associations of county quintiles with cancer mortality were assessed for all cancers and for the 13 cancer types representing the top 10 causes of cancer deaths in males or females (lung and broncheal; colon and rectal; pancreatic; liver and intrahepatic bile duct; leukemia; esophageal; urinary bladder; non-Hodgkin lymphoma; brain and other nervous system; prostate; breast; ovarian, and uterine corpus).
Key Findings
The age-adjusted mortality rates for all cancers combined per 100,000 population were 179.8 in Q1, 177.3 in Q2, 167.6 in Q3, 159.6 in Q4, and 146.1 in Q5 counties (P < .001 for trend).
Compared with Q5 counties, adjusted mortality rate ratios were 1.22 (95% confidence interval [CI] = 1.20–1.24) for Q1, 1.17 (95% CI = 1.15–1.19) for Q2, 1.10 (95% CI = 1.09–1.12) for Q3, and 1.06 (95% CI = 1.04–1.08) for Q4 counties (P < .001 for trend).
In an analysis of the 13 cancer types representing the top 10 causes of cancer deaths, Q1 counties had significantly higher adjusted rate ratios for mortality vs Q5 counties for 12 cancer types (excluding ovarian cancer) that ranged from 1.49 for lung and broncheal cancer to 1.06 for brain and other nervous system cancer. Adjusted rate ratios across quintiles had significant P values for trend for 12 of the 13 cancer types.
The investigators concluded, “The findings of this ecological study suggest that residential racial and economic segregation is associated with higher cancer mortality at the county level, highlighting opportunities for geographically targeted cancer prevention and control efforts.”
Lu Zhang, PhD, of the Department of Public Health Sciences, Clemson University, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was supported by a Clemson University College of Behavioral, Social, and Health Sciences Research Innovation Faculty Fellowship. For full disclosures of the study authors, visit jamanetwork.com.
