Skip to main content

Main menu

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • Authors/reviewers
    • Instructions for authors
    • Submit a manuscript
    • Open access
    • COVID-19 submission information
    • Peer reviewer login
  • Alerts
  • Podcasts
  • Subscriptions
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

User menu

  • Log in
  • Subscribe
  • Contact Us
  • My Cart

Search

  • Advanced search
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

Login

European Respiratory Society

Advanced Search

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • Authors/reviewers
    • Instructions for authors
    • Submit a manuscript
    • Open access
    • COVID-19 submission information
    • Peer reviewer login
  • Alerts
  • Podcasts
  • Subscriptions

Job strain and COPD exacerbations: an individual-participant meta-analysis

Katriina Heikkilä, Ida E.H. Madsen, Solja T. Nyberg, Eleonor I. Fransson, Kirsi Ahola, Lars Alfredsson, Jakob B. Bjorner, Marianne Borritz, Hermann Burr, Anders Knutsson, Markku Koskenvuo, Aki Koskinen, Martin L. Nielsen, Maria Nordin, Krista Pahkin, Jaana Pentti, Reiner Rugulies, Paula Salo, Martin J. Shipley, Sakari B. Suominen, Töres Theorell, Ari Väänänen, Jussi Vahtera, Marianna Virtanen, Peter J.M. Westerholm, G. David Batty, Archana Singh-Manoux, Mika Kivimäki for the IPD-Work Consortium
European Respiratory Journal 2014 44: 247-251; DOI: 10.1183/09031936.00205113
Katriina Heikkilä
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: katriina.heikkila@ttl.fi
Ida E.H. Madsen
2National Research Centre for the Working Environment, Copenhagen
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Solja T. Nyberg
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Eleonor I. Fransson
3Institute of Environmental Medicine, Karolinska Institutet, Stockholm
4School of Health Sciences, Jönköping University, Jönköping
5Stress Research Institute, Stockholm University, Stockholm
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Kirsi Ahola
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Lars Alfredsson
3Institute of Environmental Medicine, Karolinska Institutet, Stockholm
6Centre for Occupational and Environmental Medicine, Stockhom County Council, Stockhom
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jakob B. Bjorner
2National Research Centre for the Working Environment, Copenhagen
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Marianne Borritz
7Dept of Occupational and Environmental Medicine, Bispebjerg University Hospital, Copenhagen
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Hermann Burr
8Federal Institute for Occupational Safety and Health (BAuA), Berlin, Germany
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Anders Knutsson
9Dept of Health Sciences, Mid Sweden University, Sundsvall
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Markku Koskenvuo
10Dept of Public Health, University of Helsinki, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Aki Koskinen
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Martin L. Nielsen
7Dept of Occupational and Environmental Medicine, Bispebjerg University Hospital, Copenhagen
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Maria Nordin
11Dept of Psychology, Umeå University, Umeå
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Krista Pahkin
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jaana Pentti
12Finnish Institute of Occupational Health, Turku
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Reiner Rugulies
2National Research Centre for the Working Environment, Copenhagen
13Dept of Public Health and Dept of Psychology, University of Copenhagen, Copenhagen, Denmark
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Paula Salo
12Finnish Institute of Occupational Health, Turku
14Dept of Psychology, University of Turku, Turku
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Martin J. Shipley
15Dept of Epidemiology and Public Health, University College London, London
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Sakari B. Suominen
16Folkhälsan Research Center, Helsinki
17Dept of Public Health, University of Turku, Turku, Finland
18Nordic School of Public Health, Gothenburg
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Töres Theorell
5Stress Research Institute, Stockholm University, Stockholm
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Ari Väänänen
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jussi Vahtera
12Finnish Institute of Occupational Health, Turku
17Dept of Public Health, University of Turku, Turku, Finland
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Marianna Virtanen
1Finnish Institute of Occupational Health, Helsinki
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Peter J.M. Westerholm
19Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
G. David Batty
15Dept of Epidemiology and Public Health, University College London, London
20Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Archana Singh-Manoux
15Dept of Epidemiology and Public Health, University College London, London
21Inserm U1018, Centre for Research in Epidemiology and Population Health, Villejuif, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Mika Kivimäki
1Finnish Institute of Occupational Health, Helsinki
15Dept of Epidemiology and Public Health, University College London, London
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

To the Editor:

Chronic obstructive pulmonary disease (COPD) is a major cause of mortality and disability worldwide [1]. The clinical course of COPD is characterised by exacerbations, which can be minor and manageable at home or in primary care, or severe, leading to hospitalisation or even death. Known causes of exacerbations include tobacco smoke, air pollution, dusts and fumes, and respiratory infections [1], [2]. One less well understood risk factor is stress, which could plausibly lead to COPD exacerbations as it can trigger inflammation [3], [4] and is associated with increased smoking [5], which are both implicated in COPD pathology [2]. Work is an important source of stress in the age groups in which COPD is typically diagnosed [1], [6]. However, we are not aware of previous investigations of work-related stress and the risk of COPD exacerbations.

In this study, we examined the associations between job strain (the most widely studied conceptualisation of work-related stress) and severe COPD exacerbations using individual-level data from 10 prospective cohort studies from the Individual Participant Data Meta-analysis in Working Populations (IPD-Work) Consortium [7]. Job strain is defined as a combination of high demands (excessive amounts of work) and low control (having little influence on what tasks to do and how to carry them out) at work.

We ascertained job strain from the participants’ responses to questions on demands and control aspects of their work at study baseline. The responses were scored and for each participant, and mean scores were calculated for job-demand items and job-control items. Based on these, participants’ job demands and job control were defined as high or low. A combination of high demands (a job demand score above the study-specific median) and low control (job control score below the study-specific median) was defined as high strain and all other combinations as no strain. Job strain was validated and harmonised across the studies [7] and modelled as a binary exposure (high strain versus no strain).

Severe COPD exacerbations were ascertained from national hospitalisation and death registers and defined as International Classification of Diseases version 9 codes 491, 492 and 496, or version 10 codes J41, J42, J43 and J44. Our analyses were adjusted for harmonised age, sex, socioeconomic position, body mass index (BMI), tobacco smoking and alcohol intake.

We modelled the study-specific associations between job strain and COPD exacerbations using Cox regression. The Schoenfeld test suggested the proportional hazards assumption to be valid. Study-specific estimates were pooled in random effects meta-analyses and heterogeneity among these quantified using the I2-statistic. All statistical analyses were conducted using Stata 11 (Stata Corporation Ltd, College Station, TX, USA), apart from study-specific analyses in the Danish studies, which were conducted using SAS 9.2 (SAS Institute Inc., Cary, NC, USA).

Our analyses were based on 92 428 males and females (median age at baseline: 42 years), of whom 451 experienced a COPD exacerbation leading to hospitalisation (n=431) or death (n=20) during the follow-up (table 1). The median length of follow-up was 10 years, ranging from 2 to 23 years, and the mean±sd age at first severe COPD exacerbation was 60±9 years. Participants with job strain at baseline had a 32% higher risk of a severe COPD exacerbation (hazard ratio (HR) 1.32, 95% CI 1.04–1.68) than those with no strain in the age and sex-adjusted analyses (table 1). However, with additional adjustment for BMI, alcohol intake, smoking and socioeconomic position, this association attenuated to the null (HR 1.10, 95% CI 0.86–1.41).

View this table:
  • View inline
  • View popup
Table 1– Participant characteristics and associations between job strain (compared with no strain) and the risk of severe chronic obstructive pulmonary disease (COPD) exacerbations

When we stratified our analyses by baseline smoking status, there was no robust evidence for an association between job strain and the risk of COPD exacerbations among baseline smokers or baseline never-smokers after adjustment for potential confounders. Among baseline ex-smokers, job strain (compared with no strain) was associated with a 2.11-fold risk of a severe exacerbation (95% CI 1.03–4.31), independently of age, sex, socioeconomic position, BMI and alcohol intake (24 539 ex-smokers, including 63 cases of severe COPD exacerbation, 15 among participants with and 48 among those without job strain). All findings were similar in the analyses with the job strain model quadrants (passive job, active job and high strain compared with low strain) as the exposure as well as in sensitivity analyses with all asthma cases excluded.

In our meta-analyses, job strain was not associated with the risk of severe COPD exacerbations, independently of age, sex, socioeconomic position, BMI, smoking and alcohol intake. We found no association between job strain and severe COPD exacerbations among baseline never-smokers or baseline smokers but, among baseline ex-smokers, job strain was associated with an approximately two-fold increased risk of a severe exacerbation. The last finding should be interpreted as hypothesis generating, as it was based on small numbers and could be a chance finding. Baseline ex-smokers with COPD may have a more advanced disease than the COPD cases in the other smoking categories and our findings may also reflect the high risk of exacerbation at advanced stages of COPD (with the disease process causing both stress and exacerbations).

An important strength of our meta-analysis was that we used a large set of prospectively collected individual-level data. Of the 10 studies, five were population-based and another five were workplace-based but included participants from across the socioeconomic range (table 1). Thus, our findings are likely generalisable to the northern European workforce. We used a validated and harmonised exposure, job strain [7], and register-based COPD outcomes, which have good coverage and which are generally not prone to recall or other biases [8]–[10]. In addition to in-patient data, the hospitalisation registers covered outpatient appointments onwards from the mid-1990s in the Finnish and Danish studies [11] and from 2003 in the UK study [12].

It is a limitation of our study that a single baseline measurement of job strain may have been too imprecise an indicator of the exposure, which may have diluted our association estimates. Further research with repeated measurements of job strain over time would clarify this issue. Another limitation is that we had no data on disease severity or lung function at baseline. Other unmeasured confounders that might have influenced our estimates and should be controlled for in future studies include occupational exposures, concurrent illnesses, social support and physical activity. Finally, as our outcomes were severe COPD exacerbations, our findings are not necessarily generalisable to mild exacerbations.

We adjusted our analyses for smoking and alcohol intake but these could plausibly be on the causal pathway between job strain and COPD exacerbations. However, previous analyses of the IPD-Work Consortium data provided no conclusive evidence for longitudinal associations of job strain with smoking or alcohol intake, though job strain was associated with increasing smoking intensity. Further research would help to understand the direction of these associations, for if smoking and alcohol were mediators, job strain might be associated with COPD exacerbations via these risk factors.

In conclusion, our meta-analyses suggest that job strain is not associated with severe COPD exacerbations, though imprecise exposure or residual confounding may have influenced our results. This investigation should therefore be considered a hypothesis-generating study to encourage further research in this area. Importantly, associations between repeated measurements of job strain and indicators of COPD severity (e.g. lung function tests) would merit further study.

Footnotes

  • Support statement: The IPD-Work Consortium supported by the European Union New OSH ERA research programme (funded by the Finnish Work Environment Fund, the Swedish Research Council for Working Life and Social Research, and the Danish National Research Centre for the Working Environment), the Academy of Finland (132944) and the BUPA Foundation (22094477). M. Kivimäki is supported by the UK Medical Research Council (K013351), the US National Institutes of Health (R01HL036310 and R01AG034454), and a professorial fellowship from the UK Economic and Social Research Council. Details of funding for each constituent study are provided on the study websites. The funding bodies had no role in the study design, data collection or analysis, decision to publish the findings, or preparation of the manuscript.

  • Conflict of interest: Disclosures can be found alongside the online version of this article at www.erj.ersjournals.com

  • Received September 10, 2013.
  • Accepted February 3, 2014.
  • © ERS 2014

ERJ Open articles are open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 3.0.

References

  1. ↵
    Global Initiative for Chronic Obstructive Lung DiseaseGlobal strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease. www.goldcopd.org/uploads/users/files/GOLD_Report_2013_Feb20.pdf Date last accessed: November 8, 2013. Date last updated: 2013
  2. ↵
    1. Bhalla DK,
    2. Hirata F,
    3. Rishi AK,
    4. et al
    . Cigarette smoke, inflammation, and lung injury: a mechanistic perspective. J Toxicol Environ Health 2009; 12: 45–64.
    OpenUrlCrossRef
  3. ↵
    1. Slavich GM,
    2. Way BM,
    3. Eisenberger NI,
    4. et al
    . Neural sensitivity to social rejection is associated with inflammatory responses to social stress. Proc Natl Acad Sci USA 2010; 107: 14817–14822.
    OpenUrlAbstract/FREE Full Text
  4. ↵
    1. Steptoe A,
    2. Hamer M,
    3. Chida Y
    . The effects of acute psychological stress on circulating inflammatory factors in humans: a review and meta-analysis. Brain Behav Immun 2007; 21: 901–912.
    OpenUrlCrossRefPubMed
  5. ↵
    1. Heikkilä K,
    2. Nyberg ST,
    3. Fransson EI,
    4. et al
    . Job strain and tobacco smoking: an individual-participant data meta-analysis of 166 130 adults in 15 European studies. PLoS ONE 2012; 7: e35463.
    OpenUrlCrossRefPubMed
  6. ↵
    1. Milczarek M,
    2. Schneider EE,
    3. Rial González E
    . OSH in Figures: Stress at Work – Facts and Figures. Luxembourg, European Agency for Safety and Health at Work, 2009.
  7. ↵
    1. Fransson EI,
    2. Heikkila K,
    3. Nyberg ST,
    4. et al
    . Job strain as a risk factor for leisure-time physical inactivity: an individual-participant meta-analysis of up to 170,000 men and women: the IPD-Work Consortium. Am J Epidemiol 2012; 176: 1078–1089.
    OpenUrlAbstract/FREE Full Text
  8. ↵
    1. Inghammar M,
    2. Engstrom G,
    3. Lofdahl CG,
    4. et al
    . Validation of a COPD diagnosis from the Swedish Inpatient Registry. Scand J Public Health 2012; 40: 773–776.
    OpenUrlAbstract/FREE Full Text
    1. Sund R
    . Quality of the Finnish Hospital Discharge Register: a systematic review. Scand J Public Health 2012; 40: 505–515.
    OpenUrlAbstract/FREE Full Text
  9. ↵
    1. Thomsen RW,
    2. Lange P,
    3. Hellquist B,
    4. et al
    . Validity and underrecording of diagnosis of COPD in the Danish National Patient Registry. Respir Med 2011; 105: 1063–1068.
    OpenUrlCrossRefPubMed
  10. ↵
    1. Lynge E,
    2. Sandegaard JL,
    3. Rebolj M
    . The Danish National Patient Register. Scand J Public Health 2011; 39: 30–33.
    OpenUrlAbstract/FREE Full Text
  11. ↵
    Health and Social Care Information Centre. Hospital Episode Statistics. 2013. www.hesonline.nhs.uk Date last accessed: November 8, 2013
View Abstract
PreviousNext
Back to top
View this article with LENS
Vol 44 Issue 1 Table of Contents
European Respiratory Journal: 44 (1)
  • Table of Contents
  • Table of Contents (PDF)
  • About the Cover
  • Index by author
Email

Thank you for your interest in spreading the word on European Respiratory Society .

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Job strain and COPD exacerbations: an individual-participant meta-analysis
(Your Name) has sent you a message from European Respiratory Society
(Your Name) thought you would like to see the European Respiratory Society web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Print
Citation Tools
Job strain and COPD exacerbations: an individual-participant meta-analysis
Katriina Heikkilä, Ida E.H. Madsen, Solja T. Nyberg, Eleonor I. Fransson, Kirsi Ahola, Lars Alfredsson, Jakob B. Bjorner, Marianne Borritz, Hermann Burr, Anders Knutsson, Markku Koskenvuo, Aki Koskinen, Martin L. Nielsen, Maria Nordin, Krista Pahkin, Jaana Pentti, Reiner Rugulies, Paula Salo, Martin J. Shipley, Sakari B. Suominen, Töres Theorell, Ari Väänänen, Jussi Vahtera, Marianna Virtanen, Peter J.M. Westerholm, G. David Batty, Archana Singh-Manoux, Mika Kivimäki
European Respiratory Journal Jul 2014, 44 (1) 247-251; DOI: 10.1183/09031936.00205113

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

Share
Job strain and COPD exacerbations: an individual-participant meta-analysis
Katriina Heikkilä, Ida E.H. Madsen, Solja T. Nyberg, Eleonor I. Fransson, Kirsi Ahola, Lars Alfredsson, Jakob B. Bjorner, Marianne Borritz, Hermann Burr, Anders Knutsson, Markku Koskenvuo, Aki Koskinen, Martin L. Nielsen, Maria Nordin, Krista Pahkin, Jaana Pentti, Reiner Rugulies, Paula Salo, Martin J. Shipley, Sakari B. Suominen, Töres Theorell, Ari Väänänen, Jussi Vahtera, Marianna Virtanen, Peter J.M. Westerholm, G. David Batty, Archana Singh-Manoux, Mika Kivimäki
European Respiratory Journal Jul 2014, 44 (1) 247-251; DOI: 10.1183/09031936.00205113
del.icio.us logo Digg logo Reddit logo Technorati logo Twitter logo CiteULike logo Connotea logo Facebook logo Google logo Mendeley logo
Full Text (PDF)

Jump To

  • Article
    • Footnotes
    • References
  • Figures & Data
  • Info & Metrics
  • PDF
  • Tweet Widget
  • Facebook Like
  • Google Plus One

More in this TOC Section

Agora

  • Airway immune responses to COVID-19 vaccination in COPD patients
  • Wider access to rifapentine-based regimens is needed for TB care globally
  • Screening for PVOD in heterozygous EIF2AK4 variant carriers
Show more Agora

Research letters

  • Impact of depression and anxiety on exacerbation risk in bronchiectasis
  • Respiratory management of drowning-associated ARF
  • Mitochondrial DNA as biomarker of survival in RA-ILD
Show more Research letters

Related Articles

Navigate

  • Home
  • Current issue
  • Archive

About the ERJ

  • Journal information
  • Editorial board
  • Reviewers
  • Press
  • Permissions and reprints
  • Advertising

The European Respiratory Society

  • Society home
  • myERS
  • Privacy policy
  • Accessibility

ERS publications

  • European Respiratory Journal
  • ERJ Open Research
  • European Respiratory Review
  • Breathe
  • ERS books online
  • ERS Bookshop

Help

  • Feedback

For authors

  • Instructions for authors
  • Publication ethics and malpractice
  • Submit a manuscript

For readers

  • Alerts
  • Subjects
  • Podcasts
  • RSS

Subscriptions

  • Accessing the ERS publications

Contact us

European Respiratory Society
442 Glossop Road
Sheffield S10 2PX
United Kingdom
Tel: +44 114 2672860
Email: journals@ersnet.org

ISSN

Print ISSN:  0903-1936
Online ISSN: 1399-3003

Copyright © 2023 by the European Respiratory Society