Thorax 65:221-228 doi:10.1136/thx.2009.124644
  • Chronic obstructive pulmonary disease

COPD and chronic bronchitis risk of indoor air pollution from solid fuel: a systematic review and meta-analysis

  1. Jon G Ayres1
  1. 1Institute of Occupational and Environmental Medicine, School of Population and Health Sciences, University of Birmingham, Birmingham, UK
  2. 2Division of Applied Health Sciences, University of Aberdeen, Population Health Sciences, School of Medicine, Foresterhill, Aberdeen, UK
  1. Correspondence to Mr Om P Kurmi, Institute of Occupational and Environmental Medicine, School of Population and Health Sciences, University of Birmingham, Birmingham B15 2TT, UK; o.kurmi{at}
  • Received 4 August 2009
  • Accepted 11 December 2009


Background Over half the world is exposed daily to the smoke from combustion of solid fuels. Chronic obstructive pulmonary disease (COPD) is one of the main contributors to the global burden of disease and can be caused by biomass smoke exposure. However, studies of biomass exposure and COPD show a wide range of effect sizes. The aim of this systematic review was to quantify the impact of biomass smoke on the development of COPD and define reasons for differences in the reported effect sizes.

Methods A systematic review was conducted of studies with sufficient statistical power to calculate the health risk of COPD from the use of solid fuel, which followed standardised criteria for the diagnosis of COPD and which dealt with confounding factors. The results were pooled by fuel type and country to produce summary estimates using a random effects model. Publication bias was also estimated.

Results There were positive associations between the use of solid fuels and COPD (OR=2.80, 95% CI 1.85 to 4.0) and chronic bronchitis (OR=2.32, 95% CI 1.92 to 2.80). Pooled estimates for different types of fuel show that exposure to wood smoke while performing domestic work presents a greater risk of development of COPD and chronic bronchitis than other fuels.

Conclusion Despite heterogeneity across the selected studies, exposure to solid fuel smoke is consistently associated with COPD and chronic bronchitis. Efforts should be made to reduce exposure to solid fuel by using either cleaner fuel or relatively cleaner technology while performing domestic work.


  • Funding University of Birmingham.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.