Influence of smoking on serum carcinoembryonic antigen levels in subjects who underwent multiphasic health testing and services.

We quantified the effect of smoking on serum carcinoembryonic antigen (CEA) levels in 1341 subjects who underwent the multiphasic health testing and services in our center. Four hundred and sixty seven of them were smokers and the rest were nonsmokers. In males subjects, serum CEA levels were significantly higher in smokers (3.11 +/- 1.8 ng/ml) than in nonsmokers (2.14 +/- 1.8 ng/ml) (mean +/- SD; p < 0.01). For females, however, the levels had no significant differences between smokers (2.11 +/- 0.91 ng/ml) and nonsmokers (1.87 +2- 1.3 ng/ml). The CEA-positive subjects were 44, of whom 32 were male custom heavy smokers, and only 2 of them had gastrointestinal cancer. We concluded that the serum CEA level was influenced by smoking especially in males and its clinical significance for detection of carcinoma was doubtful.