The Role of Climate Change and Asthma Severity

During a session at the 2018 AAAAI Annual Meeting speakers discussed the ways climate change impacts asthma. Prior to each presentation, the speakers were presented with an award.

Isabella Annesi-Maesano, MD, PhD, DSc, of INSERM in Paris, France, discussed chemical and biological pollutants. She was presented with the AAAAI Foundation and Phil and Barbara Lieberman and Friends Lecture: Investing Together in Our Future award.

The exposome includes three domains, she shared:

• External specific exposures: physical, chemical, and biological agents/stressors; these can include smoking, diet, drugs
• External non-specific exposures: social economic stressors, lifestyle, and behavior; these can include climate, mobility, green spaces
• Internal exposures: internal chemical environment resulting from external exposure determined by internal processes, including metabolic, inflammatory, presence of xenobiotics, gut microbiome, and aging

Air pollution impacts asthma disease development, disease severity, aggravation, symptoms, and intermediate phenotypes. Many studies have demonstrated a relationship between allergen exposure and exacerbations, but the relationship to disease development is still undetermined, as studies are ongoing.

Rapid urbanization is another component of pollution, as it increases the number of megacities and leads to traffic and more air pollution. In a 2012 study published by Haahtela et al in the World Health Organization Journal, the researchers describe how the loss of biodiversity and climate change are associated with various adverse health effects. They found that altered indigenous microbiota and the general microbial deprivation characterizing the lifestyle of urban people in affluent countries appear to be risk factors for immune dysregulation and impaired tolerance. The risk is further enhanced by physical inactivity and a western diet poor in fresh fruit and vegetables, which may act in synergy with dysbiosis of the gut flora.

In a 2011 study published by Ege et al in the New England Journal of Medicine, researchers found similar results: Children living on farms were exposed to a wider range of microbes than children in the reference group, and this exposure explains a substantial fraction of the inverse relation between asthma and growing up on a farm.

“We need to reduce greenhouse gas emission, control urban settings, do more research, and improve control,” he concluded.

Nelson Augusto Rosario, MD, PhD, FAAAAI, of the Federal University of Parana in Brazil, discussed the effect of climate change on pollen and respiratory allergic disease. He was the recipient of the inaugural AAAAI Foundation and Phillip E. Korenblat, MD, FAAAAI, Lectureship Investing Together in Our Future award.

He presented a survey of AAAAI members and their opinion on climate change and health: 41% said climate change is “moderately” relevant to direct patient care and 22% said it was “a great deal” relevant. In the publication of these results, the authors wrote, “AAAAI members are witnessing medical problems caused by climate change…They support physician leadership on environmental sustainability, advocacy by physicians and their associations, and education for themselves, patients, public, and undergraduate medical students.” When asked how members think their patients are being or will be affected by climate change, nearly two-thirds reported seeing “increased care for allergic sensitization and symptoms on exposure to plants or mold.”

There is an association between carbon dioxide in air and temperature, both of which are increasing. He noted “proof” that something is changing—bird migration. “Global warming is partly to blame for the fact that birds seem to migrate earlier and earlier with each year,” said Dr. Rosario.

Air pollution leads to an increase in heavy precipitation events, pollen season, reduction of colder days, and change in atmospheric circulation patterns, to name a few. For example, pollen season is starting earlier, which is due to increasing temperatures.

He discussed a 2013 report by Barnes et al published in the Journal of Allergy and Clinical Immunology, which called for improved government control on airborne pollutants to have cleaner air and reduce respiratory disease. The allergy community must adapt by anticipating the needs of patients and by adopting practices and research methods to meet changing environmental conditions.

Cooperative responses, including international cooperation, are required to effectively mitigate greenhouse gas emissions and address other climate change issues. This can be done through complementary actions across levels, including international cooperation.

“Global warming? More like global warning. We must do something,” he concluded.

Gennaro D’Amato, MD, FAAAAI, of the University of Naples in Italy and the World Allergy Organization, discussed triggers of severe and near-fatal asthma. He received the second AAAAI Foundation and Louis M. Mendelson, MD, FAAAAI, Lectureship: Investing Together in Our Future award.

Major changes involving the atmosphere and climate have a major impact on the biosphere and human environment. Climate change is correlated with allergens for several reasons:

• Increase and faster plant growth
• Increase in the amount of pollen produced by each plant
• Increase in the amount of allergenic proteins contained in pollen
• Increase in the start time of plant growth and pollen production and earlier and longer pollen seasons

Consider molecular aerobiology in addition to counting pollen for the assessment of exposure to airborne allergens, especially in clinical trials and epidemiologic studies, he advised.

Dr. D’Amato has conducted a great deal of research on and devoted a portion of his presentation to thunderstorm-related asthma. Significant events of thunderstorm-related asthma have been described since July 6, 1983, in Birmingham, England through as recent as November 21, 2016, in Melbourne, Australia. In the Melbourne thunderstorm, nine patients died from asthma attacks. Thunderstorm asthma is triggered by large storms that can cause significant breathing problems even for healthy people.

He wrote in an article in 2017 published in Epidemiologia E Prevenzione, “The main hypothesis explaining association between thunderstorms and asthma claims that thunderstorms can concentrate pollen grains at ground level; these grains may then release allergenic particles of respirable size in the atmosphere after their rupture by osmotic shock.”

The mechanisms of these events should be known by all physicians, he stressed. In his research, Dr. D’Amato has also found that patients without asthma symptoms, but affected by seasonal rhinitis, can also experience an asthma attack. He shared the evidence on thunderstorm-related epidemics of rhinitis and asthma exacerbations:

• The occurrence of epidemics is closely linked to thunderstorms in patients with pollen allergy
• The thunderstorm-related epidemics are limited to late spring and summer when there are high levels of airborne pollen grains
• There is a close temporal association between the arrival of the thunderstorm, a major rise in the concentration of pollen grains, and the onset of epidemics
• Patients with pollen allergy who stay indoors with windows closed during the thunderstorm are not involved
• There is a major risk for patients who are not receiving the correct antiasthma treatment, but patients with allergic rhinitis and without previous asthma can experience severe bronchoconstriction

Presentation 2101: Asthma and Allergic Disorders in an Environment of Continuous Climate Change