Thunderstorm outflows preceding epidemics of asthma during spring and summer.

Guy Marks, John Colquhoun, Seaham Girgis, Hjelmroos Koski, Andrew Treloar, Peter Hansen, Sara Downs, Nicholas Car

Research output: Contribution to journalArticle

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Abstract

BACKGROUND A study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism. METHODS A case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations. RESULTS Thunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4'12 fold increase in the ambient concentration of grass pollen grains. CONCLUSIONS These findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.
Original languageEnglish
Pages (from-to)468-471
Number of pages4
JournalThorax
Volume56
Issue number6
DOIs
Publication statusPublished - 2001

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Asthma
Pollen
Air
South Australia
Weather
Poaceae
Case-Control Studies
Hospital Emergency Service
Odds Ratio
Outcome Assessment (Health Care)
Confidence Intervals

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Marks, G., Colquhoun, J., Girgis, S., Koski, H., Treloar, A., Hansen, P., ... Car, N. (2001). Thunderstorm outflows preceding epidemics of asthma during spring and summer. Thorax, 56(6), 468-471. https://doi.org/10.1136/thorax.56.6.468
Marks, Guy ; Colquhoun, John ; Girgis, Seaham ; Koski, Hjelmroos ; Treloar, Andrew ; Hansen, Peter ; Downs, Sara ; Car, Nicholas. / Thunderstorm outflows preceding epidemics of asthma during spring and summer. In: Thorax. 2001 ; Vol. 56, No. 6. pp. 468-471.
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abstract = "BACKGROUND A study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism. METHODS A case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations. RESULTS Thunderstorm outflows were detected on 33{\%} of epidemic days and only 3{\%} of control days (odds ratio 15.0, 95{\%} confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4'12 fold increase in the ambient concentration of grass pollen grains. CONCLUSIONS These findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.",
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Marks, G, Colquhoun, J, Girgis, S, Koski, H, Treloar, A, Hansen, P, Downs, S & Car, N 2001, 'Thunderstorm outflows preceding epidemics of asthma during spring and summer.', Thorax, vol. 56, no. 6, pp. 468-471. https://doi.org/10.1136/thorax.56.6.468

Thunderstorm outflows preceding epidemics of asthma during spring and summer. / Marks, Guy; Colquhoun, John; Girgis, Seaham; Koski, Hjelmroos; Treloar, Andrew; Hansen, Peter; Downs, Sara; Car, Nicholas.

In: Thorax, Vol. 56, No. 6, 2001, p. 468-471.

Research output: Contribution to journalArticle

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T1 - Thunderstorm outflows preceding epidemics of asthma during spring and summer.

AU - Marks, Guy

AU - Colquhoun, John

AU - Girgis, Seaham

AU - Koski, Hjelmroos

AU - Treloar, Andrew

AU - Hansen, Peter

AU - Downs, Sara

AU - Car, Nicholas

N1 - Imported on 12 Apr 2017 - DigiTool details were: Journal title (773t) = Thorax. ISSNs: 0040-6376;

PY - 2001

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N2 - BACKGROUND A study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism. METHODS A case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations. RESULTS Thunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4'12 fold increase in the ambient concentration of grass pollen grains. CONCLUSIONS These findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.

AB - BACKGROUND A study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism. METHODS A case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations. RESULTS Thunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4'12 fold increase in the ambient concentration of grass pollen grains. CONCLUSIONS These findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.

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DO - 10.1136/thorax.56.6.468

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JO - Thorax

JF - Thorax

SN - 0040-6376

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Marks G, Colquhoun J, Girgis S, Koski H, Treloar A, Hansen P et al. Thunderstorm outflows preceding epidemics of asthma during spring and summer. Thorax. 2001;56(6):468-471. https://doi.org/10.1136/thorax.56.6.468