Comparisons between individual- and area-level measures of socioeconomic status among childhood cancer patients: A report from the Children's Oncology Group (COG)

Observational studies often utilize area-level socioeconomic status (aSES) data when individual-level (iSES) data are unavailable. However, correlations between iSES and aSES in pediatric cancer populations are not well-described. We explored correlations between aSES and iSES in childhood cancer cases co-enrolled on Children's Oncology Group registry and epidemiology protocols (n = 1379) in the United States. We created four composite measures of iSES using maternal questionnaire data for household poverty, educational attainment, occupation, and housing type for comparison with Yost and Social Vulnerability Index (SVI) socio-economic domain at the census tract (CT)- and ZIP code (ZIP)-level. CT- and ZIP- aSES were weakly to moderately correlated with iSES (ρ_SVI=0.46, 0.36, respectively); results were similar across the four composite models (range ρ_SVI=0.43–0.48 [CT-aSES], 0.34–0.36 [ZIP-aSES]). When stratifying by race and ethnicity, the highest correlations were among non-Hispanic Black and Hispanic cases, with CT-level correlations stronger than ZIP-level. Correlations were dramatically lower for all rural cases (ρ_SVI range=-0.10–0.25), particularly non-Hispanic White (ρ_SVI range=-0.15–0.23); sample size was insufficient to evaluate other subgroups. We found varying levels of correlation between aSES and iSES, dependent upon geographic resolution of aSES measure, with CT-aSES generally being more strongly correlated with iSES than ZIP-aSES, and varying by race, ethnicity, and urbanicity.