Lung health and exposure to household air pollution in rural Malawi

Across Africa around 700 million people use biomass fuel (animal or plant material) to provide energy for cooking, heating and lighting. Women and young children experience high levels of smoke exposure when meals are cooked over open fires inside homes due to partial combustion of fuel and poor ventilation. Household air pollution from open fires is a major threat to health, ranking 4th in the recently updated World Health Organization (WHO) comparative risk assessment for the global burden of disease. WHO estimates around 4 million premature deaths are caused by household air pollution worldwide every year. A substantial proportion of these deaths is attributed to lung disease with pneumonia in young children and chronic obstructive pulmonary disease (COPD) in adult women dominating the picture. Other adverse health effects associated with biomass smoke exposure include stillbirth, low birth weight, cardiovascular disease and lung cancer.

In Malawi, where at least 95% of households depend on biomass as their main source of fuel and household air pollution levels are high, biomass smoke exposure is likely to be responsible for a substantial burden of pneumonia in young children and COPD in adults. Effective strategies for reducing both biomass fuel consumption and smoke exposure include improved stoves, ventilation, cleaner fuels and behaviour modification but are out of reach for the majority of the population due to a wide range of largely poverty-related factors. The Global Alliance for Clean Cookstoves was launched in 2010 to tackle this energy poverty issue through public private partnerships. A central aim of the Alliance is for 100 million homes to adopt clean and efficient stoves and fuels by 2020. However, there is very limited evidence to assess the potential benefits of such an approach.

The proposed research will be integrated with the Cookstoves And Pneumonia Study (CAPS) which is a £2.7 million investment from the Joint Global Health Trials Scheme in a village level cluster randomised controlled trial of an advanced cookstove intervention to prevent pneumonia in children under 5 years old in Malawi.

The proposed research will determine:
1) the association between exposure to household air pollution (carbon monoxide) and the development of pneumonia in children under the age of 5 in rural Malawi.
2) the prevalence and determinants of obstructive lung disease in adults in rural Malawi.
3) the extent to which exposure to household air pollution (carbon monoxide and particulate matter) explains the rate of decline in lung function in adults in rural Malawi.

This research is needed now to deliver relevant and timely evidence for communities and policy makers about the adverse health effects of exposure to household air pollution in Malawi and the potential for biomass smoke exposure reduction strategies to impact on the incidence of pneumonia in young children and the development and progression of COPD in adults. The results of this research will be relevant to local policy makers in Malawi who will have new data to guide decisions about prioritising funding for biomass smoke exposure reduction strategies for improving lung health; to regional commercial, non-governmental (NGO) and governmental organisations in sub Saharan Africa manufacturing and distributing cookstove solutions with uncertain health benefits; and to international decision and policy makers (e.g. DFID, WHO and Global Alliance for Clean Cookstoves) by providing new evidence about the health impacts of reducing biomass smoke exposure of broadly generalisable relevance to areas of the world where biomass fuel use is common.

Design:
1) An exposure-incidence study will be conducted within CAPS to determine the association between exposure to household air pollution (carbon monoxide [CO]) and pneumonia in children under the age of 5 in rural Malawi.
2) A cross-sectional study will be conducted to determine the prevalence and determinants of obstructive lung disease in adults in rural Malawi.
3) A prospective cohort study will be conducted within CAPS to determine the extent to which exposure to CO and particulate matter (PM2.5) explains the rate of decline in lung function in adults in rural Malawi.
Study population:
Exposure-incidence study - Children up to 5 years old included in CAPS
Cross-sectional and cohort studies - Non-institutionalised adults aged 18 and above
Exposures:
CO (Lascar CO monitors) and particulate matter (UCB particle monitors) exposures from biomass smoke
Outcomes:
Exposure-incidence study - Pneumonia in children under 5 years of aged diagnosed by blinded physicians or medical officers using the WHO Integrated Management of Childhood Illness (IMCI) pneumonia assessment protocol
Cross-sectional and cohort studies - Post bronchodilator spirometry in adults
Sample size and potential power:
Exposure-incidence study - With 2000 children this study will have 90% power to detect a minimum mean difference between the controls and cases of 6.53 (40%) ppm CO.
Cross-sectional and cohort study - With 2000 adults these studies will provide an estimate of prevalence of acceptable precision (e.g. with an estimated prevalence of 15% the estimated 95% CI for each gender would be 15% +/- 4%) and have 90% power to detect a correlation between particulate matter exposure and change in FEV1 level of 0.102 (or greater) in both age group combined and 0.144 (or greater) in each age group separately.
Consumer involvement: Villagers, local stove producers and community leaders have been involved with the development of this work.

Research participants: The proposed research will be integrated with the Cookstoves And Pneumonia Study (CAPS) which is a £2.7 million investment from the Joint Global Health Trials Scheme in a village level cluster randomised controlled trial of an advanced cookstoves intervention to prevent pneumonia in children under 5 years old in Malawi. The benefits from participation in this broader project include a quarterly allocation of maize, access to a mobile phone, access to antibiotics for pneumonia if indicated but unavailable at the local health facilities and two advanced cookstoves per household either at the beginning or end of the trial.
Local staff: A number of local people will be employed directly through this grant with many other local people involved indirectly. The training and experience gained should lead to improved work opportunities in the future. In addition there will be immediate financial benefits for individuals receiving a salary. Such financial benefits typically extend widely beyond these individuals to families and home villages.
Women and children living in poverty in developing countries: Should clear exposure-response relationships be seen between biomass smoke exposure (carbon monoxide and particulate matter) and pneumonia in children and decline in lung function in adults, these findings will be relevant across populations of people who cook using open fires living in the developing world well beyond the immediate trial setting. The benefits of reducing biomass smoke exposure could extend beyond health effects to economic, quality of life and well-being effects.
Local, national and international policy and decision makers: High quality evidence about the health and impacts possible with reductions in biomass smoke exposure is needed to inform policy and decision makers across commercial, health, development and community sectors at local, national and international levels. The results of this research will be relevant to local policy makers in Malawi who will have new data to guide decisions about prioritising funding for biomass smoke exposure reduction strategies for improving lung health; to regional commercial, non-governmental (NGO) and governmental organisations in sub Saharan Africa manufacturing and distributing cookstove solutions with uncertain health benefits; and to international decision and policy makers (e.g. DFID, WHO and Global Alliance for Clean Cookstoves) by contributing new evidence about the health impacts of reducing biomass smoke exposure of broadly generalisable relevance to areas of the world where biomass fuel use is common.
Public sector: I will work clinically at CAPS trial health centres in Malawi in place of my current NHS commitments to support local clinical services, research and teaching activities. The teaching will help maintain knowledge and skills and will hopefully have positive impacts on the management of adults and children with lung disease in Malawi.
Business: The new scientific knowledge including exposure-response data from this research could be exploited by businesses locally and internationally developing biomass smoke exposure reduction interventions. This could contribute to wealth creation and economic prosperity in individual developing countries.
Third sector: NGOs implementing cookstove programmes are expected to benefit from new knowledge about exposure-response effects of biomass smoke exposure reduction strategies that could be used to guide future activities.
Other: LSTM, MLW and COM have public engagement programmes that contribute to increasing public awareness and understanding of science, economic and societal issues which I will contribute to with the results of this research.
Environment and climate change: The widespread adoption of technologies that translate into reduced biomass use and smoke emissions will put less pressure of forests and could contribute to environmental sustainability and protection.