Pilot study of factors associated with exacerbations in chronic bronchitis.

The factors associated with exacerbations of chronic bronchitis were investigated in a pilot study of 23 male patients over a period of 29 months. There were 63 exacerbations-56 were fully investigated and in seven only serological studies were possible. Evidence of the presence of an infective agent was sought in the early stages of the exacerbations and during relative quiescence. Significantly more potential pathogens, both bacterial (pneumococci and Haemophilus influenzae) and viral and mycoplasmal, were found during exacerbations than in quiescent periods. It was not possible to demonstrate that atmospheric pollution or low temperature influenced exacerbations, but the data are insufficient to exclude a small effect.It is emphasized that the value of future work on these lines would be increased if agreement could be reached on the definition of an exacerbation.