Population density as an indicator of urban-rural differences in cancer incidence, upstate New York, 1968-1972.

This report presents cancer incidence data (1968-1972) for cities and towns in upstate New York (New York State exclusive of New York City) with various levels of urbanization as measured by population density. A direct association between population density and incidence was observed for a number of anatomic sites. A statistically significant linear trend of increasing incidence with increasing population density was observed among males and females for cancers of the buccal cavity and pharynx, esophagus, bronchus and lung, stomach and colon. For carcinomas of the liver, gallbladder, pancreas, bladder, larynx and rectum, this association was observed only among males, while, for malignant neoplasms of the brain and nervous system, only females demonstrated a statistically significant relationship between these two variables. The geographic distribution of incidence rates for the remaining sites appeared not to be related to population density. The most striking feature of these data, however, was the U-shaped pattern the authors observed for carcinomas of the uterine cervix. The observed geographic patterns tended to be consistent with data from previously published urban-rural studies and with the distribution of suspected etiologic factors.