Global climate change parallels health risks
Impact of Climate Change and Environmental Hazards on Allergic Disease
Symposium presented Saturday, February 25, 2023
Moderator
Cem Akin, MD, PhD
Professor of Internal Medicine, Division of Allergy and Clinical Immunology, University of Michigan, Ann Arbor
Presenters
Rachel L. Miller, MD
Deputy Editor, The Journal of Allergy and Clinical Immunology
Urban Chemical Exposures and Epigenetics of Allergic Disease
Lisa A. Miller, PhD
Professor of Anatomy, UC Davis School of Veterinary Medicine
Climate Change, Wildfire Smoke Exposure, and Immune Dysregulation in Asthma
Cezmi Akdis, MD
Director, Swiss Institute of Allergy and Asthma Research, Davos, and Professor, Zurich University Medical Faculty
Environmental Factors in Skin Barrier Dysfunction
Climate and environmental changes are outpacing the evolution of the human immune system.
The health consequences of climate change are far-reaching. Experts addressed 3 areas of concern: chemical exposure and asthma, the changing nature of wildfire smoke, and the effects of toxic synthetic chemicals on epithelial integrity.
Asthma risk with exposure to chemicals in consumer products
Approximately 40% of asthma cases are determined by genetics, but the remaining 60% are likely caused by environmental exposures, said Rachel L. Miller, MD, who serves as deputy editor of The Journal of Allergy and Clinical Immunology. These can include air pollution, but also chemicals such as phthalates and environmental phenols, which are used in many consumer products associated with manufacturing and food processing.
It is proposed that these chemicals can induce or exacerbate asthma because of their increased production of greenhouse gases. Further, they can cause endocrine disruption that promotes airway hypersensitivity, overall heightened allergic sensitization, and epigenetic regulation of immune-modulating genes.
Dr. Miller urged minimal exposure to these environmental chemicals, especially phthalates. “Don’t microwave food in plastic containers, don’t use plastic bags, don’t wear vinyl clothing,” she advised. She called for more legislative action, noting that although the US Food and Drug Administration has banned bisphenol A in baby bottles and sippy cups, more can be done, such as controlling environmentally dangerous chemicals in food packaging.
Wildfire smoke exposure: toxic plumes, microbe distribution
How can climate change promote the development of allergy and asthma? Ozone is formed by chemical reactions between oxides of nitrogen and volatile organic compounds that react in the presence of sunlight. This causes extreme weather, which alters and prolongs pollen production, resulting in increased exposure and severity of allergens.
Extreme wildfire events are increasing. “It’s not that there are more of them,” said Lisa A. Miller, PhD. “It’s that they are more severe when they do occur.” Wildfires enhance microbe dispersion which leads to more allergens; accordingly, recent wildfires have created half of the pollution in the western United States, explained Dr. Miller, who is professor of anatomy, UC Davis School of Veterinary Medicine.
Wildfire smoke is a significant concern beyond biomass. People may assume that smoke from wildfires is comparable to smoke from a fireplace and less destructive than combustible products released by cars. While there are similarities, there are some major differences. According to Dr. Miller, the main issue is that wildfires of today do not just burn wood; they burn buildings, including homes and businesses. The wildfire is not burning just biomass, but also manmade products, producing toxic plumes of smoke that can be carried hundreds of miles away from the original site.
Wildfire events can cause unnatural distribution of microbes, specifically fungi, which are known to be allergenic. Dr. Miller observed that there is much still to learn about the chemical makeup of wildfire smoke and how it influences the immune and respiratory systems, but wildfires and climate change clearly contribute to allergic sensitization and asthma.
Toxins in household products and epithelial barrier damage
Cezmi Akdis, MD, shared his concerns about severe health consequences of climate change, characterizing them as a global environmental and health crisis. The cause is human exposure to toxic substances that have caused epithelial barrier damage, microbial dysbiosis, and immune system activation.
This started in the 1960s, said Dr. Akdis, who is director of the Swiss Institute of Allergy and professor at Zurich University Medical Faculty. That decade saw the start of 350,000 new chemical substances being introduced into human lives, many of them pollutants that have not been clearly described. Some of the chemicals that cause the most problems are detergent surfactants, including sodium lauryl sulfate. This chemical is found in detergents, shampoos, household cleaners, toothpaste, cosmetics, and skin cleansers. It has been extracted from house dust, pillows, and bed sheets, and it has effects on skin and the airway and induces eosinophilic airway inflammation.
There are others, added Dr. Akdis. Alcohol ethoxylate is found in dishwasher rinse aids and may not be fully rinsed off dishes. Emulsifiers in packaged food that are used to extend shelf life have been shown to be toxic. Nanoplastics cause diseases of the epithelial barrier, gut barrier defects, and microbial dysbiosis.
Selected references
Akdis CA. Does the epithelial barrier hypothesis explain the increase in allergy, autoimmunity and other chronic conditions? Nat Rev Immunol 2021;21(11):739-751.
doi: 10.1038/s41577-021-00538-7
Black C, Tesfaigzi Y, Bassein JA, Miller LA. Wildfire smoke exposure and human health: Significant gaps in research for a growing public health issue. Environ Toxicol Pharmacol 2017;55:186-195. doi: 10.1016/j.etap.2017.08.022
Rappaport SM. Genetic factors are not the major causes of chronic diseases. PLoS One 2016;11(4):e0154387. doi: 10.1371/journal.pone.0154387
Wang M, Tan G, Eljaszewicz A, et al. Laundry detergents and detergent residue after rinsing directly disrupt tight junction barrier integrity in human bronchial epithelial cells. J Allergy Clin Immunol 2019;143(5):1892-1903. doi: 10.1016/j.jaci.2018.11.016
Wu M, Wang S, Weng Q, et al. Prenatal and postnatal exposure to bisphenol A and asthma: a systematic review and meta-analysis. J Thorac Dis 2021;13(3):1684-1696. doi: 10.21037/jtd-20-1550
Disclosures
There were no relevant faculty disclosures.