Poverty and childhood cancer incidence in the United States.

This study examined socioeconomic differentials in cancer incidence rates during 2000-2005 among children aged 0-19 in the United States. The data on childhood cancers, which were classified by the International Classification of Childhood Cancer, Third Edition (ICCC-3), were obtained from the Surveillance, Epidemiology, and End Results program. The socioeconomic status of residential area at diagnosis was estimated by county-level poverty rate in Census 2000, i.e., percentage of persons in the county living below the national poverty thresholds. Counties were categorized as low-, medium-, and high-poverty areas when the poverty rates were <10, 10-19.99, and 20% or higher, respectively. The results showed that medium- and high-poverty counties had lower age-adjusted incidence rates than low-poverty counties for total childhood cancers combined, central nervous system neoplasms (ICCC group III), neuroblastoma (group IV), renal tumors (group VI), and other malignant epithelial neoplasms and malignant melanomas (group XI). When the data were stratified by race, these associations were observed among whites, but not blacks. For leukemia (group I), poor counties had higher incidence rates than affluent counties for whites, but lower rates for blacks. This ecologic study provides perspective on area socioeconomic variations in childhood cancer incidence that warrants further research.