Weekly returns from the Royal College of General Practitioners research unit for acute respiratory illnesses in general practice in the United Kingdom show appreciable variation in attack rates for acute bronchitis, from a peak in January to a trough in August. In 1983, for example, it varied from 171.4 per 100 000 to 34.5 per 100 000. This pattern is identical for all years from 1976 to 1983. Attack rates are highest in the extremes of life and lowest in the 15-44 age group. As many cases of asthma are misdiagnosed as acute bronchitis, further analysis of these data will be difficult until the exact diagnostic criteria for acute bronchitis used by these general practitioners are established.
