TABLE E-1 Exposure Information on Epidemiologic Studies Involving Exposure to TCE or PCE

Reference

Study Design, Exposure, Outcomes

Exposure Assessment

Exposure Metrics

Comments

Aschengrau et al. 2003

Population-based case-control

Relative dose of PCE estimated by algorithm with variables for residential history, water flow (geometry, load on water-distribution system), pipe characteristics (such as pipe diameter, age); inputs determined from maps from local water suppliers or state DEPs

Ever vs never exposed (served by private well for entire Cape Cod residence)

Nine latency periods examined (0, 5, 7, 9, 11, 13, 15, 17, 19 years)

Cape Cod, MA

Cumulative exposure for each latency period: sum of RDDs for each residence (mass of TCE entering home in tap water over time at each address); categorized as never, low (up to and including median RDD), high RDD (above 50th, 75th, or 99th percentile)

PCE from inner vinyl liner in cement pipes distributing tap water

Breast cancer

Blair et al. 2003

Cohort study of dry cleaners

Exposure score for jobs based on published monitoring studies of dry-cleaning industry; scores increased with proximity

Exposure score assigned on basis of jobs held (cleaners, high, score of 40; pressers, sewers, counter workers, score of 7; pickup workers, low, score of 0)

Adjustment for age, sex, calendar time

PCE used as solvent in dry cleaning

Cancers, other causes of death

Little or no exposure (score of 0) vs medium-high exposure (score of 7 or 40)

Boice et al. 2006

Cohort of rocket-engine testing-facility workers

All Rocketdyne workers employed on or after Jan. 1, 1948, for 6+ mo at SSFL, nearby facilities (for comparison group); identified from personnel files, work history cards; exposed were test-stand mechanics, inspectors, test-stand engineers, research engineers; personnel listings used to place test-stand mechanics at specific stands in calendar years; descriptive industrial-hygiene information to classify potential exposure to hydrazine, TCE, other chemicals; discussions with workers

Duration of employment (years) (SMR)

Adjustment for year of birth, year of hire

Hydrazine, TCE

Potential for exposure (flush engine parts or utility solvent use) (SMR)

All causes of death

Duration of employment (RR)

4 decades of employment (RR)

Years worked as test-stand mechanic (RR)

Years worked with any potential TCE exposure (less than 4 years vs at least 4 years) (RR)

Years worked with potential TCE exposure via engine cleaning, weighted by number of engine tests (less than 4 test-years vs at least 4 test-years )



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