title: Lung function and incidence of chronic obstructive pulmonary disease after improved cooking fuels and kitchen ventilation: a 9-year prospective cohort study.
abstract: 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.
  
  
  RESULTS
  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.
  
  
  BACKGROUND
  Chinese Clinical Trial Register ChiCTR-OCH-12002398.
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Yumin
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Zou
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Shuyun
authors.initials: S
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Zhuxiang
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Fang
authors.initials: F
authors.lastname: He
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Zou
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Qiuping
authors.initials: Q
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Wenxi
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Yiling
authors.initials: Y
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Deng
authors.affiliation: First Municipal People Hospital of Shaoguan, Shaoguan, Guangdong, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang
authors.affiliation: First Municipal People Hospital of Shaoguan, Shaoguan, Guangdong, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Qiu
authors.affiliation: Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Shiliang
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Jingping
authors.initials: J
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Nanshan
authors.initials: N
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Pixin
authors.initials: P
authors.lastname: Ran
mesh_terms: D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects*; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D002681:China / Q000453:epidemiology; D003296:Cooking; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000139:chemically induced / Q000453:epidemiology*; D012129:Respiratory Function Tests; D014691:Ventilation / Q000592:standards*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter