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Retrospective Exposure Assessment for Occupational Disease of an Individual Worker Using an Exposure Database and
Derrick A Chung1, Rui Rain Yang2, Dave K Verma3
1a Workplace Safety and Insurance Board (WSIB) , Toronto , Ontario , Canada.
Journal of Occupational and Environmental Hygiene
|August 8, 2015
Summary
This study presents a method for estimating historical occupational exposures using trend analysis on large air monitoring databases. It demonstrates how temporal trends can efficiently assess worker exposure to contaminants like asbestos, even with limited historical data.
Area of Science:
- Occupational Health & Safety
- Environmental Science
- Biostatistics
Background:
- Retrospective exposure assessment is crucial for diagnosing occupational diseases.
- Estimating historical occupational exposures often relies on limited or incomplete data.
- Large air monitoring databases offer potential for robust exposure assessment.
Observation:
- A methodology was developed for retrospective exposure assessment using trend analysis on large exposure databases.
- The Medical Surveillance (MESU) asbestos dataset was used to illustrate data cleaning, analysis, and trend calculation.
- Left-censored data analysis methods, including maximum likelihood estimation (MLE), Kaplan Meier (KM), and simple substitution, were employed.
Findings:
- Trend analysis, specifically using the JoinPoint Regression Program to calculate the annual percentage change (APC), was effective in estimating historical exposure levels.
- The MLE method yielded annual mean fiber levels 44% lower than KM and substitution methods for asbestos exposure.
- APC values for asbestos exposure were -6.5% (MLE) and -7.7% (KM and substitution), indicating decreasing trends.
Implications:
- Temporal trend analysis of exposure databases provides an efficient method for estimating historical contaminant levels.
- This approach enhances the ability to assess occupational disease risk when historical exposure data is scarce.
- The methodology is applicable to various occupational settings requiring retrospective exposure assessment.
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