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Understanding Asthma

Since 2001, the total number of people with asthma has increased from 7% to 8% in the U.S. As of 2009, approximately 10% of our children were diagnosed with asthma.1 As a parent, this is a huge and worrisome number.

So what is asthma?

Asthma affects the respiratory system, causing the airways to become narrow, which limits the amount of air we can breathe into our lungs.2 Sometimes this narrowing makes our cells produce more mucus, which further limits airflow. A person with asthma will wheeze, cough, and have chest tightness and shortness of breath. Sometimes asthma ends on its own, but often it requires treatment with medication through an inhaler to open the airways. Some asthma attacks can be severe and require emergency treatment. Although asthma appears to be a lifelong disease, it can be easily controlled by medications that prevent an attack or reduce symptoms, or by avoiding by things that may trigger an attack.

So what causes asthma?

Asthma is linked to a number of common household allergens and irritants, like pet fur and dander, dust, cigarette smoke, mold, and pollen.3 A number of other common pollutants found in the air can also cause asthma, such as ozone and car exhaust. Respiratory infections as an infant or in early childhood can also cause asthma. Asthma may also be genetic.

Well, what about hairspray and cleaning products?

Some research says that cleaning products may cause wheezing in young children. Another study even suggests that exposure before birth, or during pregnancy, may increase your kids' risk of wheezing.4 Unfortunately, most studies cannot link one individual chemical or product to the increase in wheezing or asthma-like symptoms. And although we can rely on animal research to get this kind of information, animals are frequently exposed to extremely high concentrations, which do not represent our everyday exposures. In contrast, regular cleaning reduces the presence of known allergens and irritants mentioned above, and has been shown to reduce allergy and asthma symptoms.

There are many sites on the internet that provide lists of chemicals and other items that supposedly cause asthma, but not all of these sites are reliable. If you are interested in seeing if a particular chemical might cause asthma, we recommend visiting the website of the Association of Occupational and Environmental Clinics that has a searchable database (http://www.aoecdata.org/ExpCodeLookup.aspx).

A final note on causation, new research suggests that being TOO clean may actually increase your child's risk of developing asthma. Huh? In fact, the modern world has greatly increased standards of hygiene and sanitation over the years, thereby reducing the rates of disease and increasing overall health.

That's great, right?

Maybe not!

This new research, referred to as the "Hygiene Hypothesis," suggests that because our better sanitation and hygiene has decreased the number of infections that our kids get, this has actually caused an increase in asthma. Why? Because infections allow our our immune systems to develop properly, and thus any reduction in childhood infections may actually make kids MORE at risk for allergy and asthma.3 Not surprisingly, the use of antibiotics in early childhood is also linked to childhood asthma and allergy problems,6 and maybe for the same reasons. We are not allowing our kids to get healthy from their own infections by themselves, which would strengthen their immune systems.

So what can we, as parents, do to reduce our child's risk?

So are kids getting asthma because of too many allergens, or household chemicals? Or because they are not getting exposed to enough dirt? There is no real answer… yet. In the meantime, the US EPA suggests that improving indoor air quality can drastically reduce asthma and allergy symptoms (http://www.epa.gov/iaq/pubs/careforyourair.html). For more ideas on how to improve the indoor air quality of your home, visit this site from the Canadian Lung Association: http://www.lung.ca/protect-protegez/pollution-pollution/indoor-interieur/home-chezvous_e.php).


Melissa Vincent, B.A., M.S.
Associate Environmental Scientist, Toxicologoy Excellence for Risk Assessment (TERA) www.tera.org

1. Please see http://www.cdc.gov/VitalSigns/Asthma/index.html.
2. Please see lungs (http://www.nhlbi.nih.gov/health/health-topics/topics/asthma/).
3. Please see (http://www.nhlbi.nih.gov/health/health-topics/topics/asthma/causes.html).
4. Henderson, J., Sherriff, A., Farrow, A., Ayres, J. G., 2008. Household chemicals, persistent wheezing and lung function: effect modification by atopy? Eur Respir J., 31, 547-54.

5. Sherriff, A., Farrow, A., Golding, J., 2005. Frequent use of chemical household products is associated with persistent wheezing in pre-school age children. Thorax. 60, 45-49.

Chen, P., Eggleston, P.A. 2001. Allergenic proteins are fragmented in low concentrations of sodium hypochlorite. Clin Exp Allergy 31:1086-1093.

Matsui, E., Kagey-Sobotka, A., Chichester, K., Eggleston, P.A. 2003. Allergic potency of recombinant Feld 1 is reduced by low concentrations of chlorine bleach. J Allergy Clin Immunol. 111:396-401

Nickmilder, M., Carbonnelle, S., Bernard, A., 2007. House cleaning with chlorine bleach and the risks of allergic and respiratory diseases in children. Pediatr Allergy Immunol 18:27-35.

Zock, J. P., Plana, E., Anto, J., Benke, G., Blanc, P., Carosso, A., Dahlman-Hoglund, A., Heinrich, J., Jarvis, D., Kromhout, H., 2009. Domestic use of hypochlorite bleach, atopic sensitization, and respiratory symptoms in adults. J Allergy Clin Immunol. In Press.

6. See also http://www.npr.org/blogs/health/2012/03/23/149232765/why-getting-grimy-as-a-child-can-make-for-a-healthier-life.