Date of Award

January 2015

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Jonathan Borak

Second Advisor

Brian Leaderer

Abstract

Several publications have proposed a workplace risk of lung cancer in petroleum refineries, with asbestos as the potential agent. To examine the associations between petroleum refinery work and lung cancer related to occupational asbestos exposure, in addition to smoking and other concurrent occupational exposures, a systematic review and stratified meta-analysis was employed. Cochrane-Mantel-Haenszel statistics were used to combine SMR/SIR data separately for all male and female refinery workers, as well as SMR/SIR and RR/OR measurements for the subset of male maintenance workers, who were exposed to higher levels. Of 219 studies identified in the literature search, 78 studies were selected for critical review, of which 28 were used for meta-analysis. Only three studies reported estimates adjusted for smoking, the strongest risk factor of lung cancer, and of those none found a statistically significant increase for lung cancer risk. Males in cohorts consisting of all refinery workers, which included both blue and white collar workers, had a summary estimate of 0.80 (95% CI: 0.75-0.85) when compared to population controls, all female refinery workers had a summary estimate of 1.27 (95% CI: 0.86-1.87) when compared to population controls. Male maintenance workers exhibited a summary estimate of 0.88 (95% CI: 0.74-1.05) with population controls, and a summary estimate of 1.62 (95% CI: 1.30-2.03) when internally compared to other refinery workers. Subsequent sensitivity and meta-regression analyses showed generational effects, outlying studies, and significant differences between corporate and government/academic studies and between race-adjusted and non-race-adjusted studies. The present study found a lack of methodological consistency, but that overall the present literature did not provide evidence for an association between refinery work and increased lung cancer risk. Accurate quantification of lung cancer risk for refinery workers will depend on addressing these issues, particularly the contribution of smoking to lung cancer risk in this population.

Comments

This is an Open Access Thesis.

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