Proximity to Superfund Sites and Cancer Incidence in the South Atlantic United States

Public concern about environmental hazards can require health agencies to investigate patterns of cancer that seem unusual; however, measuring relationships between cancer incidence and sources of pollution can be challenging. We present ecological methods for examining cancer incidence rates and residential proximity to Superfund sites in the South Atlantic region of the U.S. We calculated population-weighted average residential proximity to Superfund sites with contaminants linked to colorectal and lung cancer for subcounty geographic areas. Using multilevel linear regression models, we estimated the relative percent change in expected 2014–2018 subcounty age-adjusted incidence rates of colorectal and lung cancers associated with increasing proximity, adjusted for the prevalence of other risk factors for cancers. We observed a 29.2% relative increase (95% confidence interval [CI] [15.0, 45.2]) in the expected subcounty age-adjusted colorectal cancer incidence rate for each one unit increase in Superfund proximity score, but no statistical association between subcounty age-adjusted lung cancer incidence rates and Superfund proximity (β = -1.9%, 95% CI [-5.3%, 1.6%]). Residential proximity to Superfund sites was associated with increased rates of colorectal cancer incidence but not lung cancer incidence. The methods presented in our analysis can be used and adapted by public health agencies to incorporate evaluation of environmental hazards into cancer surveillance practices.