Life Cycle Sessions: Prevention of Environmental Impact on Asthma
Welcome to part 3 in the Life Cycle Sessions series, providing an overview of research presented at Asthma Canada’s Breathe Easy: The Life Cycle of Asthma conference in Toronto, Ontario, on October 21, 2017. Sequential reading not required—click for part 1 on asthma (mis)diagnosis, Life Cycle Sessions: Diagnosis… Revisited and part 2 on children and asthma, Life Cycle Sessions: They'll grow out of it... or will they?
The first research project I assisted with was recruiting lower income families to a University of Alberta research study about how lower-income families navigate the realities of asthma. A core part of the U of A research focused on educating parents and families about environmental challenges within the home and how to avoid triggers common to high-density or more affordable community housing: dampness, mold, and other allergens.
In his presentation, Environmental exposure in asthma: Opportunities for prevention, Dr. Tim Takaro started by exploring the Breathe Easy Homes project of Seattle’s High Point neighborhood.1 Breathe Easy Homes expanded upon the High Point homes project’s air quality features (learn more), by including air filters, fresh air circulation, and heat recovery to improve air quality, allergen reducing flooring (linoleum, recycled content vinyl and low-pile carpet in stairs and halls, to prevent falls and reduce allergens), reduced off-gassing in wood surfaces—trim and cabinets, inclusion of vacuums with HEPA filters, special doormats and best practices for construction and cleaning including additional "dry out time” in the construction process, protecting construction materials from weather (both to prevent mold growth), protecting ductwork to minimize dust spreading, and cleaning with non-allergenic, low/non-toxic cleaners, and promoting evaporation of off-gassing from necessary areas and products.2
A Case Study: The impact of Breathe Easy Homes and environment management
Dr. Takaro told the story of David, a fifteen-year-old who grew up in the High Point neighborhood. David had begun struggling with severe asthma, and his disease prevented him from playing basketball as he wanted to.1 Within two years of moving into a Breathe Easy home, alongside 34 other families, David’s mom reported to the study team that they still kept his medicine on hand, but he rarely had to use his inhalers anymore—reporting David had since achieved his goal of making the basketball team.1 Essentially, David’s asthma went into remission, a significant factor was likely that he was not exposed to the triggers he had been exposed to in his previous living environment.
Defining the environment and precautions
Now, here’s something interesting I learned from Dr. Takaro. In the context of asthma, environment, is everything except genetics. Environment is the physical environment, but also psychosocial factors and microbial influences that affect a person’s health and, in this situation, their asthma.1 One aspect of the previous talk that Dr. Takaro built on was that of the CHILD Study’s environmental research, in which samples were collected from a child’s living environment, including allergens, tobacco smoke, endotoxins, dampness, mould, semivolatile organic compounds (off-gassing from new carpet, cabinets, etc.), as well as outdoor air pollution (specifically particulate matter 2.5), and assessing traffic nearby 1. As well, Dr. Takaro noted that the CHILD Study also looked at “exposure mapping” for other areas a child is frequently in—grandparents homes, school, or daycare.2
By measuring what types of asthma triggers were within a child’s living or care environments, the study team could make a plan for intervention 1—Breathe Easy homes are one such intervention to improve asthma control. Pets were also part of the assessment, however, factors involved with pets and their influence on asthma—such as individual genetics of animals, as I’ve written on before, and when a child first was exposed to a pet—can have massive impact on their individual sensitivity.1 Dr. Takaro noted it is also often hard to determine what may be triggering someone’s asthma in the home, because there are so many potential allergens and irritants they may be exposed to at once.1 Of all environmental factors, dust mite exposure is the only allergen that has been been demonstrated in numerous studies to be causal of asthma.1
Back to the Hygiene Hypothesis
There is some indication that certain factors may be associated with lower risk of developing asthma, or have some “protective” factor, known as the hygiene hypothesis—essentially, over sterilization leads to under-development of the immune system, and hyper-responsiveness/reactivity—a la asthma and allergies. As Dr. Takaro said… “Let them eat dirt!”1
I gleefully texted a mom I know whose children regularly hide and find random “floor food” of less-perishable natures (cookies, wagon wheels) and eat it, saying: “I am pretty sure your children are mitigating their asthma/allergy risk: ‘Overcrowding, unhygenic conditions, and larger family size are associated with lower asthma prevalence in early life’.”
This is a family of six, with two children who were born premature, and so far, nobody has asthma or allergies. And hey, if it works, bring on the floor food—even mom’s best efforts sweeping three-plus times a day and washing the floor daily isn’t a match for four boys, the middle two of whom would probably be Easter egg hiding experts with how they can re-hide pieces of the same donut four times… And seriously, her general acceptance of floor food makes me less wary every time a kid drops a Rice Krispy Treat or an apple onto the couch to eat later..!
If the hygiene hypothesis stands, well, I’ve got my fingers crossed these kids aren’t getting asthma either way!
Practicalities: Take-home messages
Eat dirt! Just kidding. Well, maybe not really… Here are Dr. Takaro’s final thoughts on the role of the environment and asthma:
- CHILD Study related research notes that use of chemical cleaning products may increase asthma risk (via impact to the infant’s gut micro-biome and impact on immune system development).3
- While not always preventable, the intestinal micro-biome, early life infection and antibiotic exposures, and c-section birth, all are correlated with higher risk of asthma.4
- Family history: children with a first degree relative who has asthma, or two first degree relatives with IgE mediated allergy, are more likely to develop asthma 1
- Exposure to cleaners or air pollution prior to asthma diagnosis, or perfumes, pets, etc. after diagnosis, impacts asthma.2
- Keeping humidity in the home below 50% reduces mould and house dust mites.1
- “Carpeting doesn’t make sense in general”, plush carpeting is bad if you have asthma.1
- Avoid fragrances, cosmetics and cleaning products that contain phthalates. Avoid allergens.1
- Assess school environment: heat or air conditioning—clean air is important in schools as children spend so much time there!1
While managing all environmental factors in the home and out can be difficult, keeping an eye on the things Dr. Takaro listed can help people with asthma to breathe easier at home and in the community. While not everyone is going to live in a Breathe Easy Home, hopefully these are some tips you can take with you for your next home renovation or move, so you can find a more asthma-friendly environment for you and your family!
What impact does your living environment have on your asthma? Discuss in the comments!
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