Veracity of disability claimants' self-reports of current smoking status. Comparison of carboxyhemoglobin levels from disability claimant and reference population.

Carboxyhemoglobin level (%COHB) obtained during pulmonary function testing was used as a measure of recent tobacco smoking among persons claiming to be nonsmokers and ex-smokers. Asbestos disability applicants and reference routine clinical patients had similar mean %COHB (2.09 +/- 1.34 and 1.99 +/- 0.88, respectively) and proportions with abnormally elevated %COHB (35 and 46 percent, respectively, had %COHB greater than 2 percent). However, comparisons of persons claiming to be ex-smokers and nonsmokers showed that the ex-smokers had higher mean %COHB (p less than 0.001 by analysis of variance) and proportions with elevated %COHB. This study suggests that disability applicants and routine clinical patients do not differ in veracity of self-stated smoking information, but many persons claiming to be ex-smokers are actually not.