Abstract

The suggestion that inhalers might on average leave a greater length of cigarette unsmoked was supported in a study of miners and ex-miners aged 35 to 64 years living in the Rhondda Fach. Non-inhalers, detected in an earlier random sample survey, were matched with inhalers, for age, radiological category of pneumoconiosis, and number of cigarettes smoked daily. Cigarette ends were collected for one day from all the men. The ends were measured by one observer who knew nothing about the smoking habits of the men submitting them. In each ten-year age group, the length of unsmoked cigarette was slightly shorter in non-inhalers than in inhalers, and the difference of 1·28 mm. was just significant (p = 0·05). The biological implications of this small difference are discussed.