FCEHA RESEARCH PROGRAM #2 (INDOOR AIR QUALITY)

Topic: Asthma and Exposure To Environmental Triggers Including Mold

Asthma is characterized by intermittent reversible airway obstruction, occurring as a result of chronic airway inflammation and hyperresponsiveness to a variety of stimuli. The precise pathogenic mechanisms for both the bronchospastic and inflammatory components that characterize asthma remain poorly understood. A variety of environmental exposures have been linked to increased risk of developing asthma and/or the exacerbation of asthma. Since children living in temperate climates spend an estimated 90% of their time indoors, that environment may play an important role.

Major indoor triggers of asthma include environmental tobacco smoke (ETS); irritants such as commercial products (paints, cleaning agents, pesticides, perfumes); components of building structures (sealants, plastics, adhesives, insulation materials); animal and insect allergens (such as dander and cockroach antigen); and molds. Although most agents that exacerbate asthma in children are inhaled, asthma may be exacerbated in some atopic individuals who touch (eg, latex) or ingest (eg, peanuts) certain products. Outdoor air pollution has also been associated with asthma exacerbations. Motor vehicle emissions contribute significantly to nitrogen oxides, hydrocarbons, diesel particles, and other airborne particulate matter. Asthma morbidity and deaths among children and young people have increased vastly during the last decade, especially in developed countries including USA. Among persons under the age of 20, the prevalence of asthma increased by 42% between 1980 and 1987.

Molds are most prominent in climates with increased ambient humidity, although some can grow in relatively dry areas. For instance, Alternaria spp is a common indoor mold in the arid climate of Arizona. Other species of common indoor mold—including Aspergillus, Penicillium, and Cladosporium—also require sufficient moisture for growth, and household areas with high humidity (e.g., basements, crawlspaces, ground floors, bathrooms, and areas with standing water such as air conditioner condensers) are where mold growth is most commonly found. Carpeting, ceilings, and paneled or hollow walls are also common reservoirs.

Epidemiologic studies have suggested an association between damp, moldy homes and asthma symptoms.

Some other potential health effects associated with mold exposure are the following: 1) allergic reactions, 2) cough, 3) skin and eye irritation, 4) other respiratory complaints, and 5) skin diseases. Some molds produce potentially toxic substances called mycotoxins, which may be pathogenic in animals and or humans and may give rise to liver or kidney cancers, immunosupression or damage to the nervous system.

Though long-term exposure to indoor mold growth may eventually become unhealthy to anyone, some groups may be affected sooner than others.

These are the following: 1) infants and children, 2) elderly, 3) individuals with pre-existing respiratory conditions, and 4) people with suppressed immune systems (for example, people with HIV, chemotherapy patients, organ transplant recipients)

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