Ambient pollen concentrations and emergency department visits for asthma and wheeze

Abstract

Background Previous studies report associations between aeroallergen exposure and asthma exacerbations. Aeroallergen burdens and asthma prevalence are increasing worldwide and are projected to increase further with climate change, highlighting the importance of understanding population-level relationships between ambient pollen concentrations and asthma. Objective To examine short-term associations between ambient concentrations of various pollen taxa and emergency department (ED) visits for asthma and wheeze in the Atlanta metropolitan area between 1993 and 2004. Methods We assessed associations between the three-day moving average (lag 0-1-2) of Betulaceae (except Alnus), Cupressaceae, Quercus, Pinaceae (except Tsuga), Poaceae, and Ambrosia pollen concentrations and daily asthma and wheeze ED visit counts, controlling for covarying pollen taxa and ambient pollutant concentrations. Results We observed a 2–3% increase in asthma and wheeze ED visits per standard deviation increase in Quercus and Poaceae pollen and a 10–15% increased risk on days with the highest concentrations (comparing the top 5% of days to the lowest 50% of days). A standard deviation increase in Cupressaceae concentrations was associated with a 1% decrease in ED visits. The association for Quercus pollen was strongest for children age 5 to 17 years. Effects of Ambrosia pollen on asthma exacerbations were difficult to assess in this large-scale temporal analysis due to possible confounding by the steep increase in circulating rhinoviruses every September. Conclusion Poaceae and Quercus pollen contribute to asthma morbidity in Atlanta. Altered Quercus and Poaceae pollen production due to climate change could affect allergen-induced asthma morbidity in the southeastern United States.

Climate Change. A Global Threat to Cardiopulmonary Health

“…Experimental studies have found reduced lung function and increased pulmonary inflammation in subjects with asthma exposed to pollen (57,58). Numerous studies in temperate climates have found increases in asthma and wheeze-related ED visits in association with high pollen concentrations (59)(60)(61)(62). Some studies have linked asthma outbreaks to thunderstorms with peaks in allergen release (51,52,63).…”

Challenges for Allergy Diagnosis in Regions with Complex Pollen Exposures

“…In addition to grasses, other pollens, such as Oleaceae, Amaranthaceae, Cupressaceae, Asteraceae, and Urticaceae, play a significant clinical role [2,3]. In North America, there are pollen regions coincident with European ones with the added complexity of greater tree diversity and a high incidence of ragweed pollinosis [4,5]. Ragweed pollinosis was exported at the beginning of the twentieth century to central Europe and has steadily increased since then [6,7].…”

The Effect of Climate Change and Air Pollution on Allergenic Potential of Pollens

“…The mechanism which is leading to these consequences could be: a) because of higher temperature we could face a longer pollen seasons (it seems that if the pollen concentrations remain at high value for several consecutive days then people predisposed to allergic diseases and patients with asthma could develop a full allergic response) (Darrow et al, 2012); b) wet conditions and especially thunderstorms (which are increasing because of climate change) will produce a rupture of pollen grains and release smaller part of their content, these smaller parts are respirable particles (0.5-2 μm) and could go to lower airways and trigger an asthma attack (grass pollens, particularly, after rupture by osmotic shock will release a high quantity of paucimicronic allergenic particles) (D' Amato, 2011;D' Amato et al, 2013); c) wind speed (could trigger production and dissemination) and transition of cold fronts (cold air induce bronchoconstriction in asthmatic patients); because of environmental changes, land use and long transportation allergenic pollens could arrive in new areas and will induce new sensitizations in people with atopic predisposition who did not have prior allergies to that type of pollen (Cecchi et al, 2010).…”