Lung function and incidence of chronic obstructive pulmonary disease after improved cooking fuels and kitchen ventilation: a 9-year prospective cohort study

PLoS Med. 2014 Mar 25;11(3):e1001621. doi: 10.1371/journal.pmed.1001621. eCollection 2014 Mar.


Background: Biomass smoke is associated with the risk of chronic obstructive pulmonary disease (COPD), but few studies have elaborated approaches to reduce the risk of COPD from biomass burning. The purpose of this study was to determine whether improved cooking fuels and ventilation have effects on pulmonary function and the incidence of COPD.

Methods and findings: A 9-y prospective cohort study was conducted among 996 eligible participants aged at least 40 y from November 1, 2002, through November 30, 2011, in 12 villages in southern China. Interventions were implemented starting in 2002 to improve kitchen ventilation (by providing support and instruction for improving biomass stoves or installing exhaust fans) and to promote the use of clean fuels (i.e., biogas) instead of biomass for cooking (by providing support and instruction for installing household biogas digesters); questionnaire interviews and spirometry tests were performed in 2005, 2008, and 2011. That the interventions improved air quality was confirmed via measurements of indoor air pollutants (i.e., SO₂, CO, CO₂, NO₂, and particulate matter with an aerodynamic diameter of 10 µm or less) in a randomly selected subset of the participants' homes. Annual declines in lung function and COPD incidence were compared between those who took up one, both, or neither of the interventions. Use of clean fuels and improved ventilation were associated with a reduced decline in forced expiratory volume in 1 s (FEV₁): decline in FEV₁ was reduced by 12 ml/y (95% CI, 4 to 20 ml/y) and 13 ml/y (95% CI, 4 to 23 ml/y) in those who used clean fuels and improved ventilation, respectively, compared to those who took up neither intervention, after adjustment for confounders. The combined improvements of use of clean fuels and improved ventilation had the greatest favorable effects on the decline in FEV₁, with a slowing of 16 ml/y (95% CI, 9 to 23 ml/y). The longer the duration of improved fuel use and ventilation, the greater the benefits in slowing the decline of FEV₁ (p<0.05). The reduction in the risk of COPD was unequivocal after the fuel and ventilation improvements, with an odds ratio of 0.28 (95% CI, 0.11 to 0.73) for both improvements.

Conclusions: Replacing biomass with biogas for cooking and improving kitchen ventilation are associated with a reduced decline in FEV₁ and risk of COPD.

Trial registration: Chinese Clinical Trial Register ChiCTR-OCH-12002398.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Air Pollutants / adverse effects*
  • Air Pollution, Indoor / adverse effects*
  • China / epidemiology
  • Cooking*
  • Female
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Particulate Matter / adverse effects
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / chemically induced
  • Pulmonary Disease, Chronic Obstructive / epidemiology*
  • Respiratory Function Tests
  • Ventilation / standards*


  • Air Pollutants
  • Particulate Matter

Associated data

  • ChiCTR/OCH-12002398

Grants and funding

Supported by Chinese Central Government Key Research Projects of the 10th National 5-year Development Plan Grants 2001BA703B03(A) (P.R.), the National Key Technology R&D Program of the 12th National Five-year Development Plan 2012BAI05B01 (P.R.), and Special Fund for Health-scientific Research in the Public Benefit of Ministry of Health (201002008). The funders had no role in design, collection, analysis, interpretation of data, writing of the report, and in the decision to submit the article for publication.