Lung cancer mortality in World War I veterans with mustard-gas injury: 1919-1965.

A study of the mortality experience of three samples of World War I veterans totaling 7,151 U.S. white males was extended from 1956 through 1965 to learn whether a single exposure to mustard gas with respiratory injury was associated with increased risk of lung cancer in later life. Rosters of men born between 1889 and 1893 [2,718 exposed to mustard gas, 1,855 hospitalized with pneumonia in 1918, and 2,578 with wounds of the extremities (controls)] were traced via the Veterans Administration's death records. The 4,136 deaths reported were 95% of that expected. The conclusions of the original study were not altered by the additional 10 years of follow-up. Observed deaths from lung cancer numbered 69, or 2.5% for the mustard-gas group as compared to 33, or 1.8%, for the pneumonia group and 50, or 1.9%, for the controls. The risk of death from lung cancer among men gassed relative to that for the controls was estimated as 1.3, with 95% confidence limits of 0.9-1.9. These figures failed to make a strong case for a carcinogenic effect, apparently because a suffcient dose of mustard gas was not received,