Occupational Asthma: a US Overview and a Start on Understanding the Problem Here

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Occupational Asthma a US Overview and a Start on
Understanding the Problem Here George A. Conway,
MD,MPH Alaska Field Station National Institute
for Occupational Safety and Health
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Work-related Asthma

• WRA most commonly reported occupational disease
  in several countries.
• 15-23 of new-onset asthma cases in adults
  work-related.
• CA, MA, MI and NJ maintained WRA surveillance
  systems during 1993-1999 the following slides
  present findings from this data surveillance.

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SENSOR

• Sentinel Event Notification System for
  Occupational Risks
• NIOSH-funded and coordinated
• While scope of program includes other diseases
  and locales, work-related asthma (WRA)
  surveillance in CA, MA, MI, and NJ
• Case definition used
• A. HC professionals Dx c/w asthma and
• B. Assoc. between symptoms of asthma and work.

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Which sources did SENSOR States use most to
identify cases of WRA during 19931999?
Distribution and number of WRA cases for all four
SENSOR states by source of report, 1993-1999.
Reports from health care professionals were the
primary source for identifying WRA cases 88
were identified through physician reports.
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How were WRA cases distributed by occupation in
SENSOR States during 19931999?
Operators, fabricators and laborers accounted for
the largest proportion of WRA cases, followed by
managerial and professional specialty
occupations.
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How were cases of WRA distributed by industry in
SENSOR States during 19931999?
Manufacturing and services accounted for the
largest proportions of WRA cases (41.4 and
34.2, respectively).
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Which agents were most frequently associated with
WRA during 19931999?
During 19931999, the largest proportion of WRA
cases was associated with miscellaneous chemicals
(19.7). This category of agents includes many
exposures that are not easily classified (for
example, perfumes, odors, and glues).
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Hypersensitivity Pneumonitis

• Distinct Dx from asthma, but often inter-related
  and differentiation can be vague or difficult.
  Asthma can and does occur frequently in patients
  with HP.
• Hypersensitivity pneumonitis is a lung disease
  that is often related to occupation. This
  inflammation of the lungs is caused by repeated
  inhalation of foreign substances such as organic
  dust, fungus, or mold. Examples of this disease
  are farmers lung, mushroom workers lung, and
  bird fanciers disease.
• The annual number of deaths from this cause are
  increasing. An HP pt. may die from acute asthma.
• Prevention of one (generally by limiting pop.
  exposure) may prevent or reduce occurrence of the
  other.

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How did the pattern of mortality from
hypersensitivity pneumonitis change during
19791999?
The annual number of hypersensitivity pneumonitis
deaths generally increased during 19791999, from
fewer than 15 per year in 1979 to 57 in 1999.
Hypersensitivity pneumonitis was designated as
the underlying cause of death in at least half of
deaths associated with hypersensitivity
pneumonitis for every year except 1982.
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How did mortality rates for hypersensitivity
pneumonitis differ by State?
States with higher hypersensitivity pneumonitis
mortality rates during 19901999 were in the
upper Midwest, the northern Plains and Mountain
States, and New England. In the group of States
with the highest mortality from hypersensitivity
pneumonitis, rates ranged from three to five
times the U.S. rate of 0.2 per million.
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How is hypersensitivity pneumonitis mortality
distributed by sex and race?
Nearly 29 of hypersensitivity pneumonitis deaths
occurred in women during 19901999. White
residents accounted for 95.7 of hypersensitivity
pneumonitis deaths during this period.
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Crab Asthma in Alaska

• Crab Asthma Summary of NIOSH investigation (HHE)
  at the request of company management.
• Objectives
• Understand nature of respiratory illness in crab
  processing workers.
• Identify sources of exposure
• Identify relationships between crab processing
  exposures and respiratory health
• Develop strategies to prevent illness in crab
  processing workers.

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What was done

• Medical and environmental assessment done
• Medical
• Symptoms questionnaire
• PFTs
• Blood collection
• Environmental
• Air sampling
• Aerosolized protein
• Crab allergens
• Endotoxins
• Microscopic analysis
• Caveat Small population size

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Findings

• Data shows
• Development of new respiratory symptoms and
  asthma among workers during the six week season.
• Appeared to be work-related.
• Higher prevalence of sensitization to crab among
  new workers suggest that workers susceptible to
  respiratory illness related to crab processing
  may be more likely to succumb to the healthy
  worker effect.

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Crab Asthma findings, continued

• The agent causing respiratory symptoms was not
  fully characterized.
• Exposure assessment did not allow evaluation of
  dose-response relationships.

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Recommendations

• Medical screening for early detection of
  respiratory symptoms
• Worker education
• PPE
• Hazard identification
• MSDS
• Engineering controls
• Enclose spray generating tasks
• Ventilation modification
• Administrative controls
• Restrict personnel exposure to essential workers
• Prohibit smoking in facility and dormitories

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Recommendations

• PPE in exposure areas
• Respirators least effective
• Respirators trial use in symptomatic workers
• Impervious clothing
• Gloves
• Aprons
• Rain suits
• Footwear
• Face shields

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Work Related Asthma WorkgroupGoal 1 to
understand the extent of the problem of
occupational asthma in Alaska.

• Objectives
• Agree on surveillance case definition for
  occupational asthma.
• 2) Review all available germane data sources
  (e.g., workers' comp., death certificates), for
  frequency of occupational asthma illness death.
• 3) Check available denominator data, then
  calculate population-specific rates for this
  condition.

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Objectives, continued

• 4) Consider and plan for sentinel surveillance ,
  perhaps in known high-risk industries, e.g.,
  seafood processing, wood products manufacturing,
  mining, and building trades.
• 5) Consider/evaluate feasibility of assessing
  frequency of known problems in AK, e.g., crab
  asthma, and pulmonary manifestations of latex
  allergy.

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Goal 2 to plan for an appropriate and responsive
program to prevent occupational asthma in the
state.

• Objectives
• Organize and apply the findings of surveillance
  data analyses (above).
• 2) Disseminate these findings, particularly to
  potential stakeholders and at-risk workers.
• 3) Consult stakeholders and involve them in
  planning for interventions based on data.