Occupational exposure and the risk of Barrett's esophagus: a case-control study

Our plain-English summary of Occupational exposure and the risk of Barrett's esophagus: a case-control study, by Z. Qureshi, D. Ramsey, J.R. Kramer, et al (Digestive Diseases and Sciences, 2013).

The study

• Authors: Z. Qureshi, D. Ramsey, J.R. Kramer, L. Whitehead, H.B. El-Serag
• Journal: Digestive Diseases and Sciences
• Published: 2013;58(7):1967-75
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Case-control studies in the United States and Europe have linked occupational exposure to volatile sulfur compounds, solvents, and pesticide to increased risk of esophageal adenocarcinoma. However, the association between occupational exposures and the risk of Barrett's esophagus (BE) is unclear given the absence of studies in this area.

Methods: This is a case-control study in patients undergoing endoscopy who were either referred directly or were eligible for screening colonoscopy and recruited from primary care clinics. All participants completed a survey on (1) self-reported occupational exposures to asbestos, metal dust, organic solvents, and pesticides, and (2) self reported longest held job and job-related activities. The latter were assigned by an industrial hygienist who was blinded to the case and control status into one of 99 standard occupational categories used by the US Department of Labor. Each occupational category was then assigned an expected level of exposure to the same four classes of agents in addition to radiation. We compared the self-reported exposure and the expected occupational exposure based on the self-reported occupation between cases with definitive BE and controls without BE. We examined the associations adjusting for age, sex, race, and patient recruitment source in a multivariable logistic regression analysis.

Results: We examined 226 cases of definitive BE and 1,424 controls without BE. There was a greater proportion of patients with self-reported asbestos exposure in cases than controls (16.2 % vs. 12.0 %; p = 0.08) but no significant differences in metal dust, organic solvents, or pesticides. The multivariate model did not show an independent association between self-reported asbestos exposure and BE. For the calculated occupational exposure, there were no significant differences between cases and controls for asbestos (29.6 % vs. 27.5 %; p = 0.5), metal dust, organic solvents, pesticides, or radiation exposure. Among commonly reported occupation, there were significantly greater proportion of retail sales workers in BE cases than controls (10.8 % vs. 4.9 %; p = 0.01).

Conclusions: Exposure to asbestos and sedentary jobs may be risk factors for Barrett's esophagus. Further studies are needed to confirm this finding.

In plain English

This case–control study asked whether workplace exposures were linked to Barrett's esophagus. The authors compared 226 veterans with biopsy-confirmed Barrett's esophagus and 1,424 without it. Participants, mostly men, were recruited from 2008 at the Michael E. DeBakey VA Medical Center, Houston. Before endoscopy, participants reported exposure to asbestos, metal dust, organic solvents or pesticides (over 8 hours weekly for at least a year). An industrial hygienist coded each person's longest-held job into an occupational category, and the researchers assigned each category estimated exposure levels. Self-reported asbestos exposure was 16.2% in cases versus 12.0% in controls (p = 0.08), which the authors called a trend. After adjustment, the odds ratio was 1.11 (95% CI 0.73–1.70). Job-based asbestos estimates showed no association (adjusted odds ratio 0.99, 95% CI 0.71–1.38). Among those in the 20 most common occupations, retail sales work was more common in cases (17 of 158, 10.8%) than controls (50 of 1,025, 4.9%). The authors concluded that asbestos exposure and sedentary jobs may be risk factors needing further study. They noted that self-reports were not externally validated and that the design cannot establish cause.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case–control study, with cases and controls selected from two cross-sectional studies at one VA medical center
• Who was studied: Veterans at the Michael E. DeBakey VA Medical Center in Houston, Texas. Some were scheduled for elective upper endoscopy (from February 2008). Others were eligible for screening colonoscopy and attended primary care clinics (September 2008 to December 2010). The study compared 226 cases with definitive (biopsy-confirmed) Barrett's esophagus and 1,424 controls without Barrett's esophagus. Mean age was about 61, and most were men (97.3% of cases, 91.6% of controls).
• Exposure: Self-reported occupational exposure to asbestos (fiber type not specified), metal dust, organic solvents and pesticides for more than 8 hours per week over 1 year or longer. In addition, a Certified Industrial Hygienist, blinded to case status, coded each person's longest-held job into a standard occupational category. The researchers then assigned each occupational code an estimated degree of exposure (0–3 scale) to these agents plus radiation.
• Main results:
  • Self-reported asbestos exposure was reported by 16.2% of cases versus 12.0% of controls (p = 0.08), described as a trend toward association. Table 2 gives 36 (15.9%) of 226 cases and 169 (11.9%) of 1,424 controls, with an unadjusted odds ratio of 1.41 (95% CI 0.96–2.09).
  • After adjustment, the association between self-reported asbestos exposure and Barrett's esophagus was weaker: adjusted odds ratio 1.11 (95% CI 0.73–1.70, p = 0.62).
  • Self-reported exposure to metal dust, organic solvents or pesticides was not associated with Barrett's esophagus.
  • Job-based estimated asbestos exposure (any level, 1 to 3) applied to 67 (29.6%) of 226 cases and 392 (27.5%) of 1,424 controls. The adjusted odds ratio was 0.99 (95% CI 0.71–1.38, p = 0.96). Estimated exposures to metals, solvents, pesticides and radiation also showed no significant associations.
  • Among participants in the 20 most common occupations (158 cases and 1,025 controls), retail sales work was the only occupation significantly more common in cases. It applied to 17 (10.8%) of 158 cases versus 50 (4.9%) of 1,025 controls (relative proportion 2.21, p = 0.01).
• The authors' conclusion: The authors concluded there was a possible association between self-reported asbestos exposure, sedentary jobs and increased risk of Barrett's esophagus. They said the asbestos association was seen only in unadjusted analyses and that future studies need to confirm these associations.
• Limitations the authors state:
  • As a case–control study, it cannot support causal inferences.
  • It was a community-based rather than industry-based study, with no quantitative exposure data.
  • Exposures were self-reported without external validation, so misclassification from faulty recall was possible.
  • Only the longest-held job was recorded, so some exposures may have been missed.
  • Participants were veterans, mostly low-income men, so generalizability to other groups is unknown.
  • Numbers in each occupation group were small, and the retail-worker association was tenuous.
  • Self-reported and job-based asbestos estimates gave inconsistent results.

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Case-Control Study, Adenocarcinoma, Endoscopy, Asbestos Exposure.

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