Cigarette smoker's bronchitis: the effect of relighting.

Male volunteers for mass radiography examination aged 40 or more were questioned about their sputum production, smoking habits, and, when applicable, their method of smoking cigarettes.Of 5,438 cigarette smokers 1,051 (19%) claimed that when smoking a cigarette they usually extinguished it at some stage and later relit it to smoke again. Anyone who admitted to producing sputum from his chest on most days of the year or on most days for a minimum of three months of the year for at least the last two years was classed, in the absence of other causative disease, as a chronic bronchitic. Such chronic bronchitics totalled 1,864 (34%).The rate of chronic bronchitis among relighters (39.7%) was higher than the rate (32.9%) among the remaining cigarette smokers. The difference was of high statistical significance (P<0.001), and the same pattern was maintained when age and consumption were standardized. After allowing for a trend towards lower social class and a preference for plain as opposed to filter cigarettes the rate of chronic bronchitis among relighters was about 15% greater than that of the remaining cigarette smokers.