Tobacco smoking among chrysotile asbestos workers in Asbest in the Russian Federation

Our plain-English summary of Tobacco smoking among chrysotile asbestos workers in Asbest in the Russian Federation, by A. Olsson, E.V. Kovalevskiy, M. Talibov, et al (Occupational and Environmental Medicine, 2020).

The study

• Authors: A. Olsson, E.V. Kovalevskiy, M. Talibov, M. Moissonnier, G. Byrnes, L. Bouaoun, S.J. Schonfeld, E. Feletto, S.V. Kashanskiy, E. Ostroumova, H. Kromhout, I.V. Bukhtiyarov, J. Schüz
• Journal: Occupational and Environmental Medicine
• Published: 2020;77(9):623-627
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: A historical cohort study of cancer mortality is being conducted among workers in a chrysotile mine and its enrichment factories in the town of Asbest, Russian Federation. Because individual-level information on tobacco use is not available for Asbest Chrysotile Cohort members, a cross-sectional survey of smoking behaviours was conducted among active and retired workers.

Methods: Self-administered questionnaires were completed by active workers during meetings organised by occupational safety personnel. Retired workers completed questionnaires during meetings of the Veterans Council or were interviewed via telephone or in person. Of the respondents, 46% could be linked to the Asbest Chrysotile Cohort. Among those, logistic regression models were used to assess associations between smoking and cumulative dust exposure.

Results: Among men, smoking prevalence was high and relatively consistent across birth decades (average, 66%), and was similar in workers across all levels of cumulative dust exposure (p trend, 0.44). Among women, the prevalence increased from <10% in those born before 1960 to 30% in those born after 1980, and smoking was associated with exposure to dust versus not exposed to dust (p value, 0.006), but did not vary appreciably across workers in different cumulative dust exposure categories (p trend, 0.29).

Conclusions: Our study suggests that cross-sectional surveys may be a useful tool for understanding the potential health impact from smoking in occupational cohorts, including possible confounding by smoking. This survey showed that adjustment at the age group level among women is needed to reduce residual confounding and account for smoking patterns, which have changed substantially over time.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

In plain English

The authors surveyed smoking habits among active and retired workers of JSC Uralasbest, which runs a chrysotile asbestos mine and enrichment factories in Asbest, Russian Federation, because a separate cancer study of these workers lacked individual smoking information. From January to June 2017, 7425 people (3692 men and 3733 women) returned usable questionnaires. Of these, 66% of men and 9% of women had ever smoked. Among women, ever-smoking rose from under 10% in those born before 1960 to 30% in those born after 1980. For 4583 respondents linked to cohort records of estimated cumulative occupational dust exposure, men's smoking did not vary with dust level (p for trend 0.44). Dust-exposed women smoked more often than unexposed women (7.1% to 7.5% versus 3%, p 0.006), but among exposed women smoking did not vary appreciably by dust level (p 0.29). The authors concluded that confounding by smoking may not be a major issue in the cancer analyses, but that age-group adjustment is needed for women. They noted possible cautious answering at workplace meetings, recall bias, and a survivor effect in the oldest groups.

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: Cross-sectional questionnaire survey of smoking behaviour, with part of the respondents linked to an existing historical cohort study (the Asbest Chrysotile Cohort) for dust exposure estimates
• Who was studied: Active and retired workers of JSC Uralasbest (chrysotile mine and enrichment factories), Asbest, Sverdlovsk Region, Russian Federation. Of 8090 completed questionnaires, 665 were excluded, leaving 7425 respondents (3692 men, 3733 women; response rate 74%; 40% active, 60% retired). 4583 respondents could be linked to the cohort's exposure data.
• Exposure: Cumulative occupational dust exposure (mg/m3-years) at a chrysotile asbestos mine and enrichment factories. It was estimated from company dust measurements through a job exposure matrix and grouped as non-exposed or by tercile (under 49.8, 49.8 to 97.3, over 97.3).
• Main results:
  • Ever-smoking prevalence was 66% among men and 9% among women (all 7425 respondents)
  • Among men, smoking prevalence was highest (over 70%) in those born 1961 to 1980 and slightly lower in earlier and later birth decades (p trend 0.00015)
  • Among women, ever-smoking increased by birth decade, from under 10% in women born before 1960 to 30% in those born after 1980 (p trend less than 0.0001)
  • Most male ever-smokers (over 70% of men born after 1950) reported more than 10 cigarettes per day, whereas women generally reported 10 or fewer
  • Among linked men, smoking did not vary with cumulative dust exposure. Birth-year-adjusted ORs versus non-exposed were 1.01 (0.64 to 1.58), 0.99 (0.62 to 1.54) and 0.90 (0.56 to 1.43) across terciles; p for trend 0.44; p non-exposed versus exposed 0.91.
  • Among linked women, 3% of non-exposed versus 7.1% to 7.5% of dust-exposed women were ever-smokers (p 0.006). Adjusted ORs were 2.11 (1.09 to 4.49), 2.57 (1.33 to 5.47) and 2.92 (1.53 to 6.17) across terciles; overall p for trend 0.002.
  • Among dust-exposed women only, smoking did not trend upward with exposure level (p 0.29)
  • Restricted to heavy smokers (more than 10 cigarettes per day) among men, no association between dust exposure and smoking was found (p 0.23). Women heavy smokers were too few to analyse (n=17).
  • Analyses by work area (mine only, enrichment factories only, both) gave results similar to the overall results but less precise
• The authors' conclusion: The authors concluded that smoking did not appear to be associated with levels of cumulative dust exposure, so confounding by smoking may not be a major issue in the cancer mortality analyses. They added that adjustment at the age-group level is needed for women, whose smoking patterns changed substantially over time.
• Limitations the authors state:
  • Questionnaires filled in at mandatory workplace meetings may have led some workers to give cautious answers for fear of negative consequences from their employer
  • Only 17% of invited active workers gave their names, which was needed for linkage to cohort exposure data
  • Retrospective reporting of smoking may be subject to recall bias
  • Smokers may be under-represented in the oldest age groups because smokers were more likely to have died before the survey (survivor effect)
  • Women who smoked were more often interviewed at home than never-smokers (p 0.009)
  • About 60% of respondents did not answer the current smoking question, so analyses used ever-smoking status
  • Self-reported work histories were not detailed enough for linkage, so the dust analyses were limited to respondents identifiable by name and date of birth

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile, Cohort Study, Confounding.

Related studies

• Cancer mortality in chrysotile miners and millers, Russian Federation: main results (Asbest Chrysotile Cohort-Study) — J. Schüz, E. Kovalevskiy, et al. (2024)
• Occupational cohort study of current and former workers exposed to chrysotile in mine and processing facilities in Asbest, the Russian Federation: Cohort profile of the Asbest Chrysotile Cohort study — J. Schüz, I. Bukhtiyarov, et al. (2020)
• Comparison of Two Information Sources for Cause-of-Death Follow-up in the Russian Federation: The Asbest Chrysotile Cohort Study — J. Schüz, E. Kovalevskiy, et al. (2020)
• A comparison of parallel dust and fibre measurements of airborne chrysotile asbestos in a large mine and processing factories in the Russian Federation — E. Feletto, S.J. Schonfeld, et al. (2017)
• Developing a company-specific job exposure matrix for the Asbest Chrysotile Cohort Study — E. Feletto, E.V. Kovalevskiy, et al. (2022)
• A retrospective cohort study of cancer mortality in employees of a Russian chrysotile asbestos mine and mills: study rationale and key features — J. Schüz, S.J. Schonfeld, et al. (2013)

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