Ecologic correlates of cancer mortality patterns in an industrialized urban population

Cancer mortality data for the period 1968-80 were analyzed to examine whether the high cancer burden for the city of Philadelphia was "evenly" distributed spatially and, if not, whether this distribution could be associated with socioeconomic variables and air pollution. Areas with significantly higher-than-expected rates tended to cluster; lung cancer and non-lung cancers showed distinctive cluster patterns, which were evident only for males; female rates for any cancer or groups of cancers were almost uniformly distributed over the neighborhoods. Both the high lung cancer and the high non-lung cancer clusters were characterized by low socioeconomic status, but only the high lung cancer clusters exhibited high levels of air pollution. These neighborhood characteristics suggested that socioeconomic variables explain non-lung cancer mortality patterns; socioeconomic variables, together with air pollution, could be responsible for the observed lung cancer patterns. The uniform distribution of female lung cancer rates suggested that air pollution by itself cannot be a prominent factor in lung cancer mortality.