Blue-collar work is a risk factor for developing IgG4-related disease of the biliary tract and pancreas

Our plain-English summary of Blue-collar work is a risk factor for developing IgG4-related disease of the biliary tract and pancreas, by L.M. Hubers, A.R. Schuurman, J. Buijs, et al (JHEP Reports, 2021).

The study

• Authors: L.M. Hubers, A.R. Schuurman, J. Buijs, N. Mostafavi, M.J. Bruno, R.C.H. Vermeulen, A. Huss, H.R. van Buuren, U. Beuers
• Journal: JHEP Reports
• Published: 2021;3(6):100385
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background & Aims: Immunoglobulin G4-related disease (IgG4-RD) of the biliary tract and pancreas is a fibroinflammatory disease of unknown origin with striking male predominance. We aimed to investigate whether blue-collar work and occupational contaminant exposure are risk factors for IgG4-RD of the biliary tract and pancreas.

Method: We performed an age-/sex-matched case-control study in the largest academic medical centers of the Netherlands. Occupational history was surveyed by questionnaires. The International Standard Classification of Occupations (ISCO88) was used to classify jobs. Job exposure matrices ALOHA and DOM were utilized to assess the years individuals were exposed to compounds. The disease control cohort consisted of patients from 6 equally sized groups. Conditional logistic regression was used to assess effects of blue-collar work and exposure to occupational contaminants on developing IgG4-RD of the biliary tract and pancreas.

Results: Overall, 101 patients with IgG4-RD of the biliary tract and pancreas were matched 1:3 to 303 controls. Patients with IgG4-RD had a lower level of education (p = 0.001). Individuals who at least once performed blue-collar work (>1 year), had higher odds of developing IgG4-RD than individuals that only performed white-collar work (odds ratio [OR] 3.66; CI 2.18-6.13; p <0.0001). Being ever exposed (>1 year) to industrial ALOHA (e.g. mineral dust; vapors-dust-gases-fumes) and DOM compounds (e.g. asbestos) resulted in higher odds of IgG4-RD (OR 2.14; 95% CI 1.26-3.16; p <0.001 and OR 2.95; 95% CI 1.78-4.90; p <0.001, respectively).

Conclusion: Blue-collar work is a risk factor for developing IgG4-RD of the biliary tract and pancreas putatively driven by exposure to selected industrial compounds; this may explain the striking male predominance among patients.

Lay Summary: Immunoglobulin G4-related disease (IgG4-RD) causes tumor-like lesions and typically affects middle-aged to elderly men. The background and cause of this disease remain relatively unknown. In this study, we identified blue-collar work as a risk factor for developing IgG4-RD of the biliary tract and pancreas, which may explain the striking male predominance among patients. Furthermore, these results suggest that toxic exposure to occupational contaminants may drive autoimmunity in IgG4-RD of the biliary tract and pancreas.

© 2021 The Author(s).

In plain English

This hospital-based case-control study asked whether blue-collar work and workplace exposures were linked to IgG4-related disease of the biliary tract and pancreas. At two Dutch academic medical centers, 101 patients with the disease were matched by age and sex to 303 patients with other digestive diseases. Job histories came from questionnaires. Exposures, including asbestos, were estimated from job titles using job exposure matrices. Of the cases, 68% had done blue-collar work for more than a year, compared with 39% of controls (odds ratio 3.66, 95% CI 2.18 to 6.13). Exposure for at least a year to compounds in the DOM matrix, which includes asbestos and other agents, was linked to higher odds than no such exposure (odds ratio 2.95, 95% CI 1.78 to 4.90). Among blue-collar workers, asbestos was one of several compounds linked to increased odds; the article text gives no separate figure for it. The authors concluded that blue-collar work is a risk factor, possibly driven by selected industrial compounds. They noted that the study was hospital-based and that specific exposures are hard to link directly to disease.

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: Age- and sex-matched hospital-based case-control study (1 case to 3 controls)
• Who was studied: 101 patients with IgG4-related cholangitis and/or autoimmune pancreatitis type 1 (IgG4-related disease of the biliary tract and pancreas), and 303 matched disease controls. The controls came from 6 equally sized groups of patients with other digestive diseases. All were seen at Amsterdam University Medical Centers and Erasmus Medical Center, Rotterdam, the Netherlands, and were included between June 2017 and December 2018.
• Exposure: Blue-collar versus white-collar work (ISCO88 classification; only jobs lasting more than 1 year were recorded), and years of occupational exposure estimated with two job exposure matrices. ALOHA covers mineral dust, biological dust, gases and fumes, solvents, pesticides, metals and other agents. DOM covers asbestos, chromium, diesel motor exhaust, nickel, polycyclic aromatic hydrocarbons, silica, animals, biological dust and endotoxin. Fiber types are not specified. Years exposed were counted regardless of exposure intensity.
• Main results:
  • 68% of cases (n = 69) had ever done a blue-collar job (counting only jobs lasting more than 1 year), compared with 39% of controls (n = 117). The odds ratio was 3.66 (95% CI 2.18 to 6.13).
  • Ever exposure for at least 1 year to any ALOHA compound was reported for 78% of cases and 62% of controls. Ever exposure for at least 1 year to any DOM compound (the matrix that includes asbestos) was reported for 73% of cases and 48% of controls.
  • Compared with people never exposed, people ever exposed (for at least 1 year) had higher odds of IgG4-related disease. The odds ratio was 2.14 (95% CI 1.26 to 3.16, p less than 0.001) for any ALOHA compound and 2.95 (95% CI 1.78 to 4.90, p less than 0.001) for any DOM compound.
  • Among blue-collar workers only, each 5 years of exposure was linked to higher odds of the disease. The odds ratio was 1.15 (95% CI 1.01 to 1.30, p = 0.03) for ALOHA compounds and 1.14 (95% CI 1.02 to 1.27, p = 0.03) for DOM compounds.
  • In a comparison limited to blue-collar workers, exposure to mineral dusts, to vapors, dusts, gases and fumes, and to asbestos was linked to increased odds of IgG4-related disease. No separate numbers for asbestos are given in the article text; they are in supplementary material.
  • Longer duration of blue-collar work showed only a trend toward higher odds that was not statistically significant (OR 1.11 per 5 years; CI 1 to 1.25; p = 0.06).
  • Cases had a lower level of education than controls.
• The authors' conclusion: The authors concluded that blue-collar work is a risk factor for IgG4-related disease of the biliary tract and pancreas, putatively driven by exposure to selected industrial compounds, and that this may explain the male predominance among patients.
• Limitations the authors state:
  • The study was hospital-based, not population-based.
  • Response rates differed between cases (84%) and controls (70%).
  • Job exposure matrices make it difficult to link specific exposures directly to disease.
  • In the post hoc analysis restricted to blue-collar workers, the case-control matching was broken.

Topics

Medical terms in this study, explained in our Lexicon: Case-Control Study, Academic Medical Center, Occupational History, Odds Ratio.

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