Proportion of lung cancers in males, due to occupation, in different areas of the USA.

Occupational data from 5 case-control studies in the United States involving 2,973 male cases and 3,210 controls were analyzed to estimate the percentage of lung cancer attributable to well-known and suspected lung carcinogens. The studies were conducted in areas heterogeneous in terms of industrial activities. The percentage of lung cancers attributable to occupations entailing potential exposure to well-recognized carcinogens ranged, by study area, from 3 to 17%. The further inclusion of occupational groups with suspect carcinogenic exposures changed these estimates very little. Exclusion of data derived from next-of-kin interviews influenced the estimates of attributable risks, but not in a systematic fashion. The estimates also varied according to ethnic group, smoking status and birth cohort, with higher values in non-whites, non-smokers and among members of more recent birth cohorts. Possible errors in exposure classification, which may make these estimates conservative, are discussed.