The relationship between the geographic distribution of lung cancer incidence and cigarette smoking in Allegheny County, Pennsylvania.

The results of the Third National Cancer Survey have shown substantial variations in lung cancer incidence rates for white males within Allegheny County, Pennsylvania. To explain these differences, two areas showing over a twofold difference in the 1970 age-adjusted incidence rates (127.7 compared to 59.0 per 100,00) were studied in greater detail. Estimates of smoking experience by age were determined in the two areas by survey sampling methods of white males 35 years of age and older. The results show the high risk area had a significantly greater proportion of males currently smoking and who had ever smoked cigarettes compared to the low risk area. Males in the high risk area also began smoking over four years earlier, and proportionally fewer men smoked filter cigarettes. Calculations of Lung cancer risk based on these results and a model of risk from the prospective and retrospective studies showed that almost all of the observed difference in risk between areas was attributable to cigarettes.