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Original research
Lung health and exposure to air pollution in Malawian children (CAPS): a cross-sectional study
  1. Sarah Rylance1,2,
  2. Rebecca Nightingale1,
  3. Andrew Naunje2,
  4. Frank Mbalume2,
  5. Chris Jewell3,
  6. John R Balmes4,
  7. Jonathan Grigg5,
  8. Kevin Mortimer1,6
  1. 1 Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
  2. 2 Lung Health Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
  3. 3 CHICAS, University of Lancaster, Lancaster, UK
  4. 4 Environmental Health Sciences Division, University of California Berkeley, Berkeley, California, USA
  5. 5 Centre for Child Health, Queen Mary University London, London, UK
  6. 6 Aintree University Hospitals NHS Foundation Trust, Liverpool, UK
  1. Correspondence to Dr Kevin Mortimer, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK; kevin.mortimer{at}


Background Non-communicable lung disease and exposure to air pollution are major problems in sub-Saharan Africa. A high burden of chronic respiratory symptoms, spirometric abnormalities and air pollution exposures has been found in Malawian adults; whether the same would be true in children is unknown.

Methods This cross-sectional study of children aged 6–8 years, in rural Malawi, included households from communities participating in the Cooking and Pneumonia Study (CAPS), a trial of cleaner-burning biomass-fuelled cookstoves. We assessed; chronic respiratory symptoms, anthropometry, spirometric abnormalities (using Global Lung Initiative equations) and personal carbon monoxide (CO) exposure. Prevalence estimates were calculated, and multivariable analyses were done.

Results We recruited 804 children (mean age 7.1 years, 51.9% female), including 476 (260 intervention; 216 control) from CAPS households. Chronic respiratory symptoms (mainly cough (8.0%) and wheeze (7.1%)) were reported by 16.6% of children. Average height-for-age and weight-for-age z-scores were −1.04 and −1.10, respectively. Spirometric abnormalities (7.1% low forced vital capacity (FVC); 6.3% obstruction) were seen in 13.0% of children. Maximum CO exposure and carboxyhaemoglobin levels (COHb) exceeded WHO guidelines in 50.1% and 68.5% of children, respectively. Children from CAPS intervention households had lower COHb (median 3.50% vs 4.85%, p=0.006) and higher FVC z-scores (−0.22 vs −0.44, p=0.05) than controls.

Conclusion The substantial burden of chronic respiratory symptoms, abnormal spirometry and air pollution exposures in children in rural Malawi is concerning; effective prevention and control strategies are needed. Our finding of potential benefit in CAPS intervention households calls for further research into clean-air interventions to maximise healthy lung development in children.

  • paediatric lung disaese
  • asthma epidemiology
  • paediatric asthma
  • lung physiology

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  • Contributors Design: KM, JG, SR. Acquisition of data: SR, RN, AN, FM, KM. Analysis of data: SR, RN, CJ, JG, KM. Interpretation of data: SR, RN, CJ, JRB, JG, KM. Writing the manuscript, approval of the version to be published and agreement to be accountable for all aspects of the work: All authors.

  • Funding This work was funded by a Research Grant from the Medical Research Foundation (Ref: MRF-021-0001-RG-MORTI), a New Investigator Research Grant from the Medical Research Council (Ref: MR/L002515/1), a Joint Global Health Trials Grant from the Medical Research Council, UK Department for International Development and Wellcome Trust (Ref: MR/K006533/1) and the Medical Research Council Doctoral Training Programme at the Liverpool School of Tropical Medicine and University of Lancaster (Ref: MR/N013514/1). Additional support was provided by the NIHR Global Health Research Unit on Lung Health and TB in Africa at LSTM—'IMPALA'. In relation to IMPALA (grant number 16/136/35) specifically: IMPALA was commissioned by the National Institute of Health Research using Official Development Assistance (ODA) funding. The views expressed in this publication are those of the author(s) and not necessarily those of the National Institute for Health Research or the Department of Health.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Ethical approval was given by the College of Medicine Research Ethics Committee in Malawi (reference P.07/16/1994) and Liverpool School of Tropical Medicine Research Ethics Committee in the UK (reference 16-040).

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

  • Data availability statement Data are available upon reasonable request.

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