Smoke intake among smokers is higher in lower socioeconomic groups

Objective-To analyse socioeconomic differences in serum thiocyanate concentrations among current smokers, and whether such differences persist after adjustment for the number of cigarettes smoked. Setting-General population of six districts of the Czech Republic in 1992. Participants-451 male and 282 female current smokers. Main outcome measure-Serum concentration of thiocyanate. Results-There was a clear educational gradient in serum thiocyanate among male smokers; car ownership and crowding were not related to thiocyanate. Age adjusted mean concentrations in men with primary, vocational, secondary, and university education were 168.6, 158.2, 148.2, and 141.8 mu mol/l, respectively (p for trend 0.032). Adjustment for the average daily number of cigarettes explained a part of this gradient. Socioeconomic differences in serum thiocyanate were not seen in women. Conclusion-The strong gradient in men suggests that smokers from lower socioeconomic groups have a preference for higher smoke intake and so may be more nicotine dependent. This finding, if confirmed, would have important implications for anti-smoking programmes.