ASTHMA AND THUNDERSTORMS - DESCRIPTION OF AN EPIDEMIC IN GENERAL-PRACTICE IN BRITAIN USING DATA FROM A DOCTORS DEPUTIZING SERVICE IN THE UK

Objective-To describe the areas affected and the scale of an epidemic of thunderstorm associated asthma on the night of 24/25 June 1994 and to explore the spatial and temporal relationship between the thunderst orm and the associated epidemic. Setting-The 29 offices of a deputisin g service for general practitioners' (GP) out of hours calls (Healthca ll). At the time of the storm the deputising service provided out of h ours cover for about 8500 out of about 30000 GPs in England, Scotland, and Wales. Methods-Patients who phoned the Healthcall offices to requ est a home visit were categorised as ''asthma'' or ''other causes'' ba sed on their presenting complaint. The number of calls on the night of 24/25 June 1994 was compared in areas affected by thunderstorms and a reas not affected by thunderstorms and with the night of 17/18 June 19 94, when there were no thunderstorms. Results-A large area of the sout h and east of England was affected by an epidemic of asthma closely re lated both temporally and spatially with the thunderstorms on 24/25 Ju ne 1994. The pooled Mantel-Haenszel estimate for the risk of asthma in thunderstorm affected areas compared with the control night was 6.36 (95% confidence interval 4.97, 8.32) compared with a value of 1.01 (0. 80, 1.27) for those not exposed. Extrapolation suggests about 1500 ext ra patients were likely to have requested a visit from a GP that night because of epidemic asthma. Conclusions-Under certain circumstances t hunderstorms are associated with asthma and can affect many patients. Deputising services are a useful source of data for the investigation of epidemics in primary care.