COPD - Background in the US

1
COPD - Background in the US

• Chronic obstructive pulmonary disease (COPD)
  includes chronic bronchitis, emphysema,
  bronchiectasis, and chronic airway obstruction.
  
• Estimated prevalence of 8.5 in the U.S.
• In 1999 COPD was the fourth leading cause of
  death in US (gt 124,000 deaths)

2
Occupational burden of COPD

• American Thoracic Society statement (2003)
  estimated 15 of COPD is caused by occupational
  exposures
• Specific agents studied to date
• silica, coal dust
• grain dust, wood dust, cement dust
• cadmium, welding fumes
• possibly isocyanates

3
COPD in construction workers

• Glencross et al. 1997 found that sheet metal
  workers followed over a 10-year period sustained
  significantly accelerated loss of FEV1 if they
  were exposed to asbestos and smoked.
• Using data from the NHANES III for 1988-1994,
  workers in construction trades have been shown to
  be at increased risk of COPD based on PFT data
  Hnizdo et al., 2002.

4
COPD in construction workers

• Oliver (2006) found that tunnel construction
  workers exposed to respirable crystalline silica
  and cement dust are at increased risk for airway
  disease. Extent of risk varied by trade and work
  activity.

5
Impact of total dust in constructionBakke 2002
Appl Occ Env Hyg

• Longitudinal accelerated decline in lung function
• Exposure to dust and gases from diesel exhaust,
  blasting, drilling and rock transport in tunnel
  work enhances the risk for accelerated decline in
  FEV1, respiratory symptoms, and COPD in tunnel
  workers compared with other heavy construction
  workers

6
Exposures to total dust in constructionBakke
2002 Appl Occ Env Hyg

• Among construction workers performing tunneling
  operations
• shotcreting operators 6.8 mg/m3
• tunnel boring machine workers 6.2 mg/m3
• shaft drilling workers 6.1 mg/m3
• outdoor concrete workers 1.0 mg/m3
• electricians 1.4 mg/m3
• support workers 1.9 mg/m3

7
Exposure assessment in US construction
(Rappaport 2003)

• Median values for respirable dust and silica
  (mg/m3 )
• Painters 13.5 total / 1.28 silica
• Laborers 2.46 total / 0.350 silica
• Bricklayers 2.13 total / 3.20 silica
• Operating engineers total 0.720 / 0.075 silica

151 personal measurements were analyzed from 80
workers on 36 construction sites
8
Questions

• Can we separate effects of different components
  of construction dust?
• Is most of the COPD due to specific agents, such
  as silica, diesel exhaust and welding fume? Or
  is there a combined impact of other nuisance
  dusts?
• Focus on epidemiology or controls?