Article Text

Original article
Cross-sectional associations between air pollution and chronic bronchitis: an ESCAPE meta-analysis across five cohorts
  1. Yutong Cai1,
  2. Tamara Schikowski2,3,4,
  3. Martin Adam2,3,
  4. Anna Buschka4,
  5. Anne-Elie Carsin5,
  6. Benedicte Jacquemin5,6,7,
  7. Alessandro Marcon8,
  8. Margaux Sanchez6,7,
  9. Andrea Vierkötter4,
  10. Zaina Al-Kanaani1,
  11. Rob Beelen9,
  12. Matthias Birk10,
  13. Bert Brunekreef9,
  14. Marta Cirach5,
  15. Françoise Clavel-Chapelon7,11,
  16. Christophe Declercq12,,
  17. Kees de Hoogh1,2,3,
  18. Audrey de Nazelle5,13,
  19. Regina E Ducret-Stich2,3,
  20. Virginia Valeria Ferretti14,
  21. Bertil Forsberg15,
  22. Margaret W Gerbase16,
  23. Rebecca Hardy17,
  24. Joachim Heinrich10,
  25. Gerard Hoek9,
  26. Debbie Jarvis1,18,
  27. Dirk Keidel2,3,
  28. Diana Kuh17,
  29. Mark J Nieuwenhuijsen5,
  30. Martina S Ragettli2,3,
  31. Andrea Ranzi19,
  32. Thierry Rochat16,
  33. Christian Schindler2,3,
  34. Dorothea Sugiri4,
  35. Sofia Temam6,7,
  36. Ming-Yi Tsai2,3,
  37. Raphaëlle Varraso6,7,
  38. Francine Kauffmann6,7,
  39. Ursula Krämer4,
  40. Jordi Sunyer5,
  41. Nino Künzli2,3,
  42. Nicole Probst-Hensch2,3,
  43. Anna L Hansell1,20
  1. 1Department of Epidemiology & Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
  2. 2Swiss Tropical and Public Health Institute, Basel, Switzerland
  3. 3University of Basel, Basel, Switzerland
  4. 4Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
  5. 5Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain
  6. 6INSERM, CESP Centre for research in Epidemiology and Population Health, U1018, Respiratory and Environmental epidemiology team, Villejuif, France.
  7. 7Université Paris Sud 11, UMRS 1018, F-94807, Villejuif, France
  8. 8Unit of Epidemiology and Medical Statistics, Department of Public Health and Community Medicine, University of Verona, Verona, Italy
  9. 9Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
  10. 10German Research Centre for Environmental Health, Institutes of Epidemiology I and II, Neuherberg, Germany
  11. 11INSERM, CESP Centre for research in Epidemiology and Population Health, U1018, Nutrition, Hormones, and Women's Health team, Villejuif, France
  12. 12French Institute for Public Health Surveillance, Saint-Maurice, France
  13. 13Centre for Environmental Policy, Imperial College London, London, UK
  14. 14Section of Biostatistics and Clinical Epidemiology, Department of Public Health, Neuroscience, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy
  15. 15Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umea University, Umea, Sweden
  16. 16Division of Pulmonary Medicine, University Hospitals of Geneva, Geneva, Switzerland
  17. 17MRC Unit for Lifelong Health and Ageing at UCL, Institute of Epidemiology and Health Care, University College London, London, UK
  18. 18Respiratory Epidemiology and Public Health Group, National Heart and Lung Institute, Imperial College London, London, UK
  19. 19Environmental Health Reference Centre, Regional Agency for Environmental Prevention of Emilia Romagna, Modena, Italy
  20. 20Directorate of Public Health and Primary Care, Imperial College Healthcare NHS Trust, London, UK
  1. Correspondence to Dr Anna Hansell, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK; a.hansell{at}


Background This study aimed to assess associations of outdoor air pollution on prevalence of chronic bronchitis symptoms in adults in five cohort studies (Asthma-E3N, ECRHS, NSHD, SALIA, SAPALDIA) participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) project.

Methods Annual average particulate matter (PM10, PM2.5, PMabsorbance, PMcoarse), NO2, nitrogen oxides (NOx) and road traffic measures modelled from ESCAPE measurement campaigns 2008–2011 were assigned to home address at most recent assessments (1998–2011). Symptoms examined were chronic bronchitis (cough and phlegm for ≥3 months of the year for ≥2 years), chronic cough (with/without phlegm) and chronic phlegm (with/without cough). Cohort-specific cross-sectional multivariable logistic regression analyses were conducted using common confounder sets (age, sex, smoking, interview season, education), followed by meta-analysis.

Results 15 279 and 10 537 participants respectively were included in the main NO2 and PM analyses at assessments in 1998–2011. Overall, there were no statistically significant associations with any air pollutant or traffic exposure. Sensitivity analyses including in asthmatics only, females only or using back-extrapolated NO2 and PM10 for assessments in 1985–2002 (ECRHS, NSHD, SALIA, SAPALDIA) did not alter conclusions. In never-smokers, all associations were positive, but reached statistical significance only for chronic phlegm with PMcoarse OR 1.31 (1.05 to 1.64) per 5 µg/m3 increase and PM10 with similar effect size. Sensitivity analyses of older cohorts showed increased risk of chronic cough with PM2.5abs (black carbon) exposures.

Conclusions Results do not show consistent associations between chronic bronchitis symptoms and current traffic-related air pollution in adult European populations.

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