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The causes and consequences of seasonal variation in COPD exacerbations.

Donaldson GC, Wedzicha JA - Int J Chron Obstruct Pulmon Dis (2014)

Bottom Line: The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure.Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels.The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

View Article: PubMed Central - PubMed

Affiliation: Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.

ABSTRACT
The time of year when patients experience exacerbations of chronic obstructive pulmonary disease is a much-overlooked feature of the disease. The higher incidence of exacerbations in winter has important consequences for patients in terms of increased morbidity and mortality. The seasonality also imposes a considerable burden on already-overloaded health care services, with both primary care consultations and hospital admissions increasing in number. The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure. The precise causes of the seasonality are unknown, but thought to be partly due to the increased prevalence of respiratory viral infections circulating in cold, damp conditions. Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels. The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

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Related in: MedlinePlus

Time-series analysis showing the time courses of respiratory mortality following a cold day.Notes: M RES describes the increase in mortality per 1°C fall in temperature. The y-axis is the regression coefficients of mortality on temperature on days before and after day 0. The horizontal line is the means of values at lag −30 to −16 days. *Peak value and significantly different from zero, P<0.001. Reproduced from J Epidemiol Community Health, Early increases in ischaemic heart disease mortality dissociated from and later changes associated with respira tory mortality after cold weather in south east England, Donaldson GC, Keatinge WR, 51(6),643–648, copyright 1997, with permission from BMJ Publishing Group Ltd.40Abbreviation: M RES, respiratory disease mortality.
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f4-copd-9-1101: Time-series analysis showing the time courses of respiratory mortality following a cold day.Notes: M RES describes the increase in mortality per 1°C fall in temperature. The y-axis is the regression coefficients of mortality on temperature on days before and after day 0. The horizontal line is the means of values at lag −30 to −16 days. *Peak value and significantly different from zero, P<0.001. Reproduced from J Epidemiol Community Health, Early increases in ischaemic heart disease mortality dissociated from and later changes associated with respira tory mortality after cold weather in south east England, Donaldson GC, Keatinge WR, 51(6),643–648, copyright 1997, with permission from BMJ Publishing Group Ltd.40Abbreviation: M RES, respiratory disease mortality.

Mentions: Deaths from COPD increase significantly during the cold weather experienced in winter, but this is generally mentioned as an adjunct to studies into the effects of atmospheric pollution.39,40 Few studies have specifically examined excess winter COPD mortality. Figure 3 shows clear seasonality in COPD deaths, which are consistently higher in winter and greater in older age-groups. An important difference between the effects of atmospheric pollutants and cold weather is that pollutants are associated with an immediate increase in COPD mortality,39 whereas temperature appears to have a delayed effect. Figure 4 shows that respiratory disease (ICD-9 460–519) peaks 12 days after a cold day.41 This difference in the delay-to-peak effect can be explained. Atmospheric pollutants cause bronchoconstriction and increased mucus production. This might be sufficient to tip the balance in already-seriously ill individuals, whereas cold might increase the likelihood of infection, which once established takes time to progress and cause death.


The causes and consequences of seasonal variation in COPD exacerbations.

Donaldson GC, Wedzicha JA - Int J Chron Obstruct Pulmon Dis (2014)

Time-series analysis showing the time courses of respiratory mortality following a cold day.Notes: M RES describes the increase in mortality per 1°C fall in temperature. The y-axis is the regression coefficients of mortality on temperature on days before and after day 0. The horizontal line is the means of values at lag −30 to −16 days. *Peak value and significantly different from zero, P<0.001. Reproduced from J Epidemiol Community Health, Early increases in ischaemic heart disease mortality dissociated from and later changes associated with respira tory mortality after cold weather in south east England, Donaldson GC, Keatinge WR, 51(6),643–648, copyright 1997, with permission from BMJ Publishing Group Ltd.40Abbreviation: M RES, respiratory disease mortality.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199860&req=5

f4-copd-9-1101: Time-series analysis showing the time courses of respiratory mortality following a cold day.Notes: M RES describes the increase in mortality per 1°C fall in temperature. The y-axis is the regression coefficients of mortality on temperature on days before and after day 0. The horizontal line is the means of values at lag −30 to −16 days. *Peak value and significantly different from zero, P<0.001. Reproduced from J Epidemiol Community Health, Early increases in ischaemic heart disease mortality dissociated from and later changes associated with respira tory mortality after cold weather in south east England, Donaldson GC, Keatinge WR, 51(6),643–648, copyright 1997, with permission from BMJ Publishing Group Ltd.40Abbreviation: M RES, respiratory disease mortality.
Mentions: Deaths from COPD increase significantly during the cold weather experienced in winter, but this is generally mentioned as an adjunct to studies into the effects of atmospheric pollution.39,40 Few studies have specifically examined excess winter COPD mortality. Figure 3 shows clear seasonality in COPD deaths, which are consistently higher in winter and greater in older age-groups. An important difference between the effects of atmospheric pollutants and cold weather is that pollutants are associated with an immediate increase in COPD mortality,39 whereas temperature appears to have a delayed effect. Figure 4 shows that respiratory disease (ICD-9 460–519) peaks 12 days after a cold day.41 This difference in the delay-to-peak effect can be explained. Atmospheric pollutants cause bronchoconstriction and increased mucus production. This might be sufficient to tip the balance in already-seriously ill individuals, whereas cold might increase the likelihood of infection, which once established takes time to progress and cause death.

Bottom Line: The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure.Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels.The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

View Article: PubMed Central - PubMed

Affiliation: Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.

ABSTRACT
The time of year when patients experience exacerbations of chronic obstructive pulmonary disease is a much-overlooked feature of the disease. The higher incidence of exacerbations in winter has important consequences for patients in terms of increased morbidity and mortality. The seasonality also imposes a considerable burden on already-overloaded health care services, with both primary care consultations and hospital admissions increasing in number. The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure. The precise causes of the seasonality are unknown, but thought to be partly due to the increased prevalence of respiratory viral infections circulating in cold, damp conditions. Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels. The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

Show MeSH
Related in: MedlinePlus