Lung cancer risk among bricklayers in a pooled analysis of case-control studies

Our plain-English summary of Lung cancer risk among bricklayers in a pooled analysis of case-control studies, by D. Consonni, S. De Matteis, A.C. Pesatori, et al (International Journal of Cancer, 2015).

The study

• Authors: D. Consonni, S. De Matteis, A.C. Pesatori, P.A. Bertazzi, A.C. Olsson, H. Kromhout, S. Peters, R.C. Vermeulen, B. Pesch, T. Brüning, B. Kendzia, T. Behrens, I. Stücker, F. Guida, H.E. Wichmann, I. Brüske, M.T. Landi, N.E. Caporaso, P. Gustavsson, N. Plato, L.A. Tse, I.T. Yu, K.H. Jöckel, W. Ahrens, H. Pohlabeln, F. Merletti, L. Richiardi, L. Simonato, F. Forastiere, J. Siemiatycki, M.É. Parent, A. Tardón, P. Boffetta, D. Zaridze, Y. Chen, J.K. Field, A. 't Mannetje, N. Pearce, J. McLaughlin, P. Demers, J. Lissowska, N. Szeszenia-Dabrowska, V. Bencko, L. Foretova, V. Janout, P. Rudnai, E. Fabiánová, R. Stanescu Dumitru, H.B. Bueno-de-Mesquita, J. Schüz, K. Straif
• Journal: International Journal of Cancer
• Published: 2015;136(2):360-71
• Cited by: 31 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Bricklayers may be exposed to several lung carcinogens, including crystalline silica and asbestos. Previous studies that analyzed lung cancer risk among these workers had several study design limitations. We examined lung cancer risk among bricklayers within SYNERGY, a large international pooled analysis of case-control studies on lung cancer and the joint effects of occupational carcinogens. For men ever employed as bricklayers we estimated odds ratios (OR) and 95% confidence intervals (CI) adjusted for study center, age, lifetime smoking history and employment in occupations with exposures to known or suspected lung carcinogens. Among 15,608 cases and 18,531 controls, there were 695 cases and 469 controls who had ever worked as bricklayers (OR: 1.47; 95% CI: 1.28-1.68). In studies using population controls the OR was 1.55 (95% CI: 1.32-1.81, 540/349 cases/controls), while it was 1.24 (95% CI: 0.93-1.64, 155/120 cases/controls) in hospital-based studies. There was a clear positive trend with length of employment (p < 0.001). The relative risk was higher for squamous (OR: 1.68, 95% CI: 1.42-1.98, 309 cases) and small cell carcinomas (OR: 1.78, 95% CI: 1.44-2.20, 140 cases), than for adenocarcinoma (OR: 1.17, 95% CI: 0.95-1.43, 150 cases) (p-homogeneity: 0.0007). ORs were still elevated after additional adjustment for education and in analyses using blue collar workers as referents. This study provided robust evidence of increased lung cancer risk in bricklayers. Although non-causal explanations cannot be completely ruled out, the association is plausible in view of the potential for exposure to several carcinogens, notably crystalline silica and to a lesser extent asbestos.

© 2014 UICC.

In plain English

This pooled analysis combined case-control studies from 13 European countries, Canada, Hong Kong and New Zealand (the SYNERGY project). It included 34,139 men (15,608 with lung cancer and 18,531 controls) recruited in 1985–2010. Men ever employed as bricklayers were compared with other men, adjusting for study center, age, lifetime smoking and employment in other jobs linked to lung cancer. Ever working as a bricklayer was associated with higher odds of lung cancer (OR 1.47, 95% CI 1.28–1.68; 695 cases, 469 controls). Risk rose with years worked as a bricklayer, with some decrease after 40 years. The association was stronger for squamous cell carcinoma (OR 1.68, 95% CI 1.42–1.98) and small cell carcinoma (OR 1.78, 95% CI 1.44–2.20) than for adenocarcinoma (OR 1.17, 95% CI 0.95–1.43). In studies using hospital or mixed controls it was weaker (OR 1.24, 95% CI 0.93–1.64), with no clear trend by years worked. The authors concluded that, although non-causal explanations cannot be completely ruled out, the association is plausible given potential exposure to several carcinogens, notably crystalline silica. They wrote that asbestos exposure in construction was most probably intermittent, occurring during specific tasks.

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: Pooled analysis of case-control studies (SYNERGY project): 16 population- or hospital-based case-control studies plus one cohort-nested case-control study
• Who was studied: 34,139 men (15,608 lung cancer cases and 18,531 controls) recruited in 1985–2010 in 13 European countries, Canada, Hong Kong and New Zealand. Women were excluded because only 6 had ever worked as bricklayers.
• Exposure: Ever employment as a bricklayer, taken from lifetime job histories, and length of that employment. Individual exposures were not measured. The authors discussed crystalline silica (quartz dust) as the main potential exposure and asbestos as intermittent, occurring during specific tasks.
• Main results:
  • All men: ever bricklayers versus never bricklayers, OR 1.47 (95% CI 1.28–1.68), adjusted for center, age, smoking and other high-risk jobs (695 cases, 469 controls ever bricklayers)
  • With additional adjustment for education the OR was 1.32 (95% CI 1.14–1.52). Using other blue collar workers as the reference group it was 1.37 (95% CI 1.19–1.57).
  • Lung cancer risk rose with length of employment as a bricklayer (trend p less than 0.001), with some decrease after 40 years
  • By cancer type: squamous cell carcinoma OR 1.68 (95% CI 1.42–1.98, 309 cases); small cell carcinoma OR 1.78 (95% CI 1.44–2.20, 140 cases); adenocarcinoma OR 1.17 (95% CI 0.95–1.43, 150 cases); p for homogeneity 0.0007
  • In the eight studies with population controls: OR 1.55 (95% CI 1.32–1.81; 540 cases and 349 controls ever bricklayers), with a clear positive trend by length of employment
  • In the seven studies with hospital or mixed controls: OR 1.24 (95% CI 0.93–1.64; 155 cases and 120 controls ever bricklayers), with no clear trend by length of employment
  • Among never cigarette smokers, the OR for bricklayers was 1.46 (95% CI 0.82–2.60), based on 15 cases and 107 controls who had been bricklayers
  • When bricklayers were combined with less specific codes (other bricklayers, stonemasons and tile setters; housebuilders; other construction workers), the OR was 1.34 (95% CI 1.21–1.48; 1,304 cases and 997 controls)
• The authors' conclusion: The authors concluded that lung cancer risk was increased among bricklayers, rising with length of employment. Although non-causal explanations cannot be completely ruled out, they judged the association plausible given potential exposure to several carcinogens, notably crystalline silica.
• Limitations the authors state:
  • Some non-differential misclassification of jobs is unavoidable, most likely biasing results towards no effect
  • Job coding of bricklayers may have differed across study centers
  • Few bricklayers had never smoked, so results for never smokers were imprecise
  • The higher risks for smoking-related cancer types could reflect residual confounding by smoking. The authors argued the length-of-employment trend supports a true association.
  • Response rates were lower for controls than for cases and varied widely across studies
  • The analysis was restricted to men

Topics

The National Library of Medicine indexes this study under subjects our site covers: Construction, Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Meta-Analysis, Crystalline, Odds Ratio, confidence interval, Relative Risk, Carcinoma, Adenocarcinoma.

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