Thunderstorm-associated asthma in an inland town in south-eastern Australia. Who is at risk?

The aim of the study was to characterize patients at risk of asthma exacerb ation during spring thunderstorms and identify potential measures to amelio rate the impact of those events. A case-control study was conducted among patients aged 7-60 yrs, who attend ed Wagga Hospital (NSW: Australia) for asthma during the period of 1 June 1 997 to 31 October 1997. One hundred and eighty-three patients who attended on 30 and 31 October 1997 were the cases and the remaining 121 patients wer e the controls. Questionnaire data were obtained from 148 (81%) eases and 9 1 (75%) controls. One hundred and thirty-eight (95%) cases who attended during the thundersto rm gave a history of hayfever prior to the event compared to 66 (74%) contr ols who attended at other times (odds ratio (OR) 6.01, 95% confidence inter val (CI) 2.55-14.15); 111 (96%) cases were allergic to rye grass pollen com pared to 47 (64%) controls (OR 23.6, 95% CI 6.6-84.3), Among subjects with a prior diagnosis of asthma (64% cases and 82% controls), controls (56%) we re more likely to be taking inhaled steroids at time of the thunderstorm th an cases (27%, OR 0.3, 95% CI 0.16-0.57). History of hayfever and allergy to rye grass are strong predictors for asth ma exacerbation during thunderstorms in spring. The lower rate of inhaled s teroid use in thunderstorm cases suggests that this treatment may be effect ive in preventing severe attacks during thunderstorms.