Housing, Asthma, and Health

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Housing, Asthma, and Health

• Eric M. Roberts, MD PhD
• June 10, 2004

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Plan

• Asthma overview (brief!)
• Why we are concerned about
• Dampness and mold
• Dust
• Cockroaches
• Pesticides
• Other environmental health issues

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What happens in asthma

• Ongoing inflammation smaller air passages fill
  up with mucous
• Episodic constriction muscles around the airway
  clamp down (asthma attack)

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Asthma severity

• In most mild cases, its just inconvenient
• If worse, a person can be intermittently unable
  to work, attend school, or play
• Bad attacks can lead to hospitalization
• Nationwide, 4,000-5,000 people die from asthma
  each year 150-200 of them are children

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Whats going on?

• In asthma, the part of the immune system related
  to allergies is poorly controlled
• Sometimes an allergy to a specific substance is
  identified, sometimes its not
• For many housing issues, allergies are the main
  culprit in contributing to asthma (substances in
  the household are allergenic)
• The manifestations of this are in the lungs

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Whats going on?

• Anything affecting either the immune system or
  the lungs could contribute to asthma
• General consensus is that both genes and the
  environment contribute to asthma

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Mold What is it?

• Members of the Fungi kingdom
• Grows in practically any climate, indoors and
  outdoors
• Need moisture and food to grow, but not sunlight
• Microscopic spores can travel through the air and
  survive drying for long periods, then proliferate

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Mold Health Effects

• People prone to allergies (e.g. those with
  asthma) manufacture antibodies to mold in their
  blood
• Some toxins produced by molds induce inflammation
  in the body
• Glucans, which are components of the cell walls
  in molds, appear to disturb immune system
  regulation

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Mold Health Effects

• About 40 studies from several counties
  demonstrate dampness or mold exposure is
  associated with respiratory symptoms,
  particularly in children
• Some studies also document fatigue, headache, and
  other symptoms are associated with exposure
• Rare species of toxigenic mold are associated
  with more serious medical conditions

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Household dust mites What are they?

• Microscopic arthropods
• Environment must be humid enough for them to
  absorb water from the air before they can
  proliferate
• Household dust mites (HDM) are a very common
  household allergen, although less so in arid
  climates

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HDM Health Effects

• HDM are elicit strong allergic reactions in
  people who are sensitive
• This has been shown to make asthma worse many
  believe HDM even play a role in causing asthma
• Allergencity is believed to be the sole mechanism
  for this effect
• Problem Very few HDM reduction interventions in
  homes have been shown to be effective in reducing
  asthma symptoms

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Cockroaches

• Congregate and multiply wherever there is food
  and moisture
• Feces cause strong allergic reactions in people
  with asthma
• Some believe exposure can lead to the development
  of asthma

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Pesticides

• Pesticides are, by definition, biologically
  active compounds
• Many both persist and spread beyond intended
  sites of use
• Metabolites of pesticides are found in most
  children, with higher levels in agricultural
  communities

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Pesticides

• They are poisonous to humans at high levels
• At low levels, animal studies have demonstrated
  many effects, including
• Growth disruption
• Abnormal brain development
• Hormonal dysregulation

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Pesticides

• No studies of long-term, low levels of pesticide
  exposures have been conducted in (human) children
• One recent study found that children who
  developed asthma were more likely to have been
  exposed to pesticides during infancy
• Possibly more important The mechanisms by which
  pesticides could effect brain development, both
  before and after birth, are very numerous and
  quite scary

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Other Environmental Health Issues

• Environmental tobacco smoke (ETS)
• Outgassing of volatile organic compounds
• Stress

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Other Environmental Health Issues

• Pollution from outdoor air
• Particulates from traffic, industry, and
  agricultural processes
• Ozone, nitrogen oxides, and sulfur oxides from
  traffic and industry
• Diesel exhaust
• Toxic releases from industry and incineration
  facilities