Population density and cancer incidence differentials in New York State, 1978-82.

Patterns of cancer incidence within five population density quintiles in New York State, exclusive of New York City, were investigated between 1978 and 1982. Sex-specific, standardized incidence ratios were calculated within each population density quintile for all cancer cases combined and for site-specific cancers based on cancer incidence patterns exhibited by the general population of New York State, exclusive of New York City. Areas with the highest population density demonstrated a 13 percent excess of cancer cases among males and a seven percent excess among females. In contrast, areas with the lowest population density exhibited lower cancer incidence, among both males (12 percent less) and females (12 percent less). Males demonstrated a significant, direct linear relationship between increasing population density and all cancer sites combined, and for cancers of the oral cavity and pharynx, esophagus, stomach, colon, rectum, liver, pancreas, larynx, lung, bladder, brain, and nervous system, and for Hodgkin's disease and multiple myelomas. Among females, a significant, direct linear relationship was observed between increasing population density and all cancer sites combined, and for cancers of the buccal cavity and pharynx, esophagus, stomach, lung, breast, and kidney. Malignant melanomas of the skin, and in situ and invasive cancers of the cervix exhibited unusual incidence patterns across the population density quintiles. These data are most useful in generating hypotheses for further studies to define specific etiologic factors operating within population density groupings. Population density, as measured in this investigation, may represent a surrogate measure for other factors which are related to cancer morbidity.