Smoking and health: the association between smoking behaviour, total mortality, and cardiorespiratory disease in west central Scotland.

The relationship of smoking to total mortality and to the prevalence of cardiorespiratory symptoms has been studied in three prospective surveys in west central Scotland in which 18 786 people attended a multiphasic screening examination. The prevalence of respiratory symptoms, and to a lesser extent cardiovascular symptoms, increased with the number of cigarettes smoked, with inhalation, and with a younger age of starting to smoke. A lower prevalence of respiratory symptoms in both sexes was observed in smokers of filter cigarettes than in smokers of plain cigarettes, and in those who smoked cigarettes with lower tar levels, irrespective of whether these were filtered or plain. In general, the relationships found between smoking and mortality were similar to those reported by other workers. Current cigarette smokers had a death rate from all causes which was twice that of those who had never smoked. No difference was found between the mortality rates of smokers of plain and filter cigarettes.