Association between household air pollution and nasopharyngeal pneumococcal carriage in Malawian infants (MSCAPE): a nested, prospective, observational study.

BACKGROUND: Household air pollution from solid fuels increases the risk of childhood pneumonia. Nasopharyngeal carriage of Streptococcus pneumoniae is a necessary step in the development of pneumococcal pneumonia. We aimed to assess the association between exposure to household air pollution and the prevalence and density of S pneumoniae carriage among children. METHODS: The Malawi Streptococcus pneumoniae Carriage and Air Pollution Exposure study was a nested, prospective, observational study of children participating in the cluster randomised controlled Cooking and Pneumonia Study (CAPS) in the Karonga Health and Demographic Surveillance System (HDSS) area in northern Malawi. CAPS compared the effects of a cleaner burning biomass-fuelled cookstove (intervention group) with traditional open-fire cooking (control group) on the incidence of pneumonia in children. Eligible children aged 6 weeks or 6 months (those recruited a 6 weeks were also followed up at age 6 months) were identified by the Karonga HDSS centre. Nasopharyngeal swabs were taken to detect S pneumoniae, and infant exposure to particulate matter with a diameter of ≤2·5 µm (PM2·5) exposure was assessed by use of a MicroPEM device. The primary outcome was the prevalence of nasopharyngeal S pneumoniae carriage in all children aged 6 months, assessed in all children with valid data on PM2·5. The effects of the intervention stoves (intention-to-treat analysis) and PM2·5 (adjusted exposure-response analysis) on the prevalence of S pneumoniae carriage were also assessed in the study children. FINDINGS: Between Nov 15, 2015, and Nov 2, 2017, 485 children were recruited (240 from the intervention group and 245 from the control group). Of all 450 children with available data at age 6 months, 387 (86% [95% CI 82-89]) were positive for S pneumoniae. Geometric mean PM2·5 exposure was 60·3 µg/m3 (95% CI 55·8-65·3) in S pneumoniae-positive children and 47·0 µg/m3 (38·3-57·7) in S pneumoniae-negative children (p=0·044). In the intention-to-treat analysis, a non-significant increase in the risk of S pneumoniae carriage was observed in intervention group children compared with control group children (odds ratio 1·36 [95% CI 0·95-1·94]; p=0·093). In the exposure-response analysis, a significant association between PM2·5 exposure and S pneumoniae carriage was observed; a one unit increase in decile of PM2·5 was found to significantly increase the risk of S pneumoniae carriage by 10% (1·10 [1·01-1·20]; p=0·035), after adjustment for age, sex, 13-valent pneumococcal conjugate vaccination status, season, current use of antibiotics, and MicroPEM run-time. INTERPRETATION: Despite the absence of effect from the intervention cookstove, household air pollution exposure was significantly associated with the prevalence of nasopharyngeal S pneumoniae carriage. These results provide empirical evidence for the potential mechanistic association between exposure to household air pollution and childhood pneumonia. FUNDING: Bill & Melinda Gates Foundation.

How is Respect and Social Inclusion Conceptualised by Older Adults in an Aspiring Age-Friendly City? A Photovoice Study in the North-West of England.

The World Health Organisation (WHO) Global Age-Friendly Cities (AFC) Guide classifies key characteristics of an AFC according to eight domains. Whilst much age-friendly practice and research have focused on domains of the physical environment, those related to the social environment have received less attention. Using a Photovoice methodology within a Community-Based Participatory Research approach, our study draws on photographs, interviews and focus groups among 26 older Liverpool residents (60+ years) to explore how the city promotes respect and social inclusion (a core WHO AFC domain). Being involved in this photovoice study allowed older adults across four contrasting neighbourhoods to communicate their perspectives directly to Liverpool's policymakers, service providers and third sector organisations. This paper provides novel insights into how: (i) respect and social inclusion are shaped by aspects of both physical and social environment, and (ii) the accessibility, affordability and sociability of physical spaces and wider social processes (e.g., neighbourhood fragmentation) contributed to or hindered participants' health, wellbeing, intergenerational relationships and feelings of inclusion and connection. Our findings suggest that respect and social inclusion are relevant across all eight domains of the WHO AFC Guide. It is core to an AFC and should be reflected in both city-based policies and evaluations.

Barriers and Facilitators to the Adoption and Sustained Use of Cleaner Fuels in Southwest Cameroon: Situating 'Lay' Knowledge within Evidence-Based Policy and Practice.

Approximately four million people die each year in low- and middle-income countries from household air pollution (HAP) due to inefficient cooking with solid fuels. Liquid Petroleum Gas (LPG) offers a clean energy option in the transition towards renewable energy. This qualitative study explored lay knowledge of barriers and facilitators to scaling up clean fuels in Cameroon, informed by Quinn et al.'s Logic Model. The model has five domains and we focused on the user and community needs domain, reporting the findings of 28 semi-structured interviews (SSIs) and four focus group discussions (FGDs) that explored the reasons behind fuel use choices. The findings suggest that affordability, safety, convenience, and awareness of health issues are all important influences on decision making to the adoption and sustained use of LPG, with affordability being the most critical issue. We also found the ability of clean fuels to meet cooking needs to be central to decision-making, rather than an aspect of convenience, as the logic model suggests. Local communities provide important insights into the barriers and facilitators to using clean fuels. We adapt Quinn et al.'s logic model accordingly, giving more weight to lay knowledge so that it is better positioned to inform policy development.

Using photovoice methods as a community-based participatory research tool to advance uptake of clean cooking and improve health: The LPG adoption in Cameroon evaluation studies.

Each year up to 2.6 million people die prematurely from household air pollution (HAP) due to cooking with polluting fuels such as wood and charcoal, particularly in low and middle-income countries (LMICs). The World Health Organisation recommends scaling the adoption of clean fuels to improve maternal and child health. Liquefied Petroleum Gas (LPG) represents a scalable clean fuel that provides health and environmental benefits when used for household energy in LMICs. In Cameroon, over 70% of people rely on biomass for cooking, and the Government aims to increase LPG use from <20% to 58% by 2030. Supporting households make this transition requires involvement of multiple stakeholders and an understanding of perspectives from the community's perspective. We used visual participatory methods 'Photovoice' to explore households' perceptions of factors influencing the uptake of LPG for cooking in South-West Cameroon. Two groups of participants from rural (n = 7) and peri-urban (n = 8) areas photographed subjects they identified as preventing and facilitating LPG uptake in their communities. Subsequently, individual interviews (n = 15) and group discussions (n = 5) explored participants' reflections on the photographs. Thematic analysis was conducted using NVivo 10 software. The main barriers identified included difficulty in affording the initial LPG equipment and ongoing refills, scarcity of LPG retail shops and refills, and safety concerns. Facilitators included (i) increasing awareness of the benefits of LPG (e.g. health), (ii) increasing retail outlet density in rural areas, (iii) addressing safety concerns (e.g. replacing damaged cylinders), and (iv) reducing the price of LPG refills. Participants presented their photos at a public exhibition, which generated discussions with key stakeholders (e.g. government ministries) about how best to assist communities in this transition. Photovoice was found to be an innovative and effective approach for exploring how to advance equitable access to LPG from a community perspective and successfully engage with key stakeholders.

Correction to: Household Determinants of Liquified Petroleum Gas (LPG) as a Cooking Fuel in South West Cameroon.

Household Determinants of Liquified Petroleum Gas (LPG) as a Cooking Fuel in South West Cameroon.

Household Determinants of Liquified Petroleum Gas (LPG) as a Cooking Fuel in South West Cameroon.

Currently 70% of the population in Cameroon are reliant on solid fuel for cooking (90% in rural communities) and the associated household air pollution contributes to significant mortality and morbidity in the country. To address the problems of energy security, deforestation and pollution the government has developed a strategy (Masterplan) to increase use of liquified petroleum gas (LPG) as a cooking fuel from 12% to 58% by 2030. As a clean fuel scaled adoption of LPG has the potential to make significant positive impacts on population health. The LPG Adoption in Cameroon Evaluation (LACE) studies are assessing in the community (i) barriers and enablers for and (ii) local interventions to support, adoption and sustained use of LPG. A census survey conducted for LACE in rural and peri-urban regions of SW Cameroon provided an opportunity to investigate current fuel use patterns and factors associated with primary and exclusive use of LPG. A cross-sectional survey of 1577 households (1334 peri-urban and 243 rural) was conducted in March 2016 using standardised fuel use and household socio-demographic questions, administered by trained fieldworkers. Wood (40.7%) and LPG (51.1%) were the most frequently reported fuels, although the dominant fuels in rural and peri-urban communities were wood (81%) and LPG (58%) respectively. Fuel stacking was observed for the majority of LPG using households (91% of peri-urban and 99% of rural households). In rural homes, a higher level of education, access to sanitation and piped water and household wealth (income and asset ownership) were all significantly associated with LPG use (p < 0.05). In peri-urban homes, younger age, access to sanitation and piped water and increasing education were significantly associated with both any and exclusive use of LPG (p < 0.05). However, whilst household wealth was related to any LPG use, there was no relationship with exclusive use. Results from this census survey of a relatively well-established LPG market with lower levels of poverty and high levels of education than Cameroon as a whole, find LPG usage well below target levels set by the Cameroon government (58% by 2030). Fuel stacking is an issue for the majority of LPG using households. Whilst, as observed here, education, household wealth and socio-economic status are well recognised predictors of adoption and sustained use of clean modern fuels, it is important to consider factors across the whole LPG eco-system when developing policies to support their scaled expansion. A comprehensive approach is therefore required to ensure implementation of the Cameroon LPG Masterplan achieves its aspirational adoption target within its stated timeframe.

The Government-led initiative for LPG scale-up in Cameroon: programme development and initial evaluation.

In 2016, the government of Cameroon, a central African country heavily reliant on wood fuel for cooking, published a Masterplan for increasing primary use of LPG from 20% to 58% of households by 2035. Developed via a multi-sectoral committee with support from the Global LPG Partnership, the plan envisages a 400 million Euro investment program to 2030, focused on increasing LPG cylinder numbers, key infrastructure, and enhanced regulation. This case study describes the Masterplan process and investment proposals and draws on community studies and stakeholder interviews to identify factors likely to impact on the planned expansion of LPG use.

An analysis of efforts to scale up clean household energy for cooking around the world.

Approximately 3 billion people, most of whom live in Asia, Africa, and the Americas, rely on solid fuels (i.e. wood, crop wastes, dung, charcoal) and kerosene for their cooking needs. Exposure to household air pollution from burning these fuels is estimated to account for approximately 3 million premature deaths a year. Cleaner fuels - such as liquefied petroleum gas, biogas, electricity, and certain compressed biomass fuels - have the potential to alleviate much of this significant health burden. A wide variety of clean cooking intervention programs are being implemented around the world, but very few of these efforts have been analyzed to enable global learning. The Clean Cooking Implementation Science Network (ISN), supported by the U.S. National Institutes of Health (NIH) and partners, identified the need to augment the publicly available literature concerning what has worked well and in what context. The ISN has supported the development of a systematic set of case studies, contained in this Special Issue, examining clean cooking program rollouts in a variety of low- and middle-income settings around the world. We used the RE-AIM (reach, effectiveness, adaptation, implementation, maintenance) framework to coordinate and evaluate the case studies. This paper describes the clean cooking case studies project, introduces the individual studies contained herein, and proposes a general conceptual model to support future planning and evaluation of household energy programs.

The prevalence of and factors associated with tobacco smoking behavior among long-distance drivers in Lagos, Nigeria.

BACKGROUND: Factors associated with tobacco smoking are useful in designing tobacco control programs. OBJECTIVES: To estimate the prevalence of and factors associated with tobacco smoking among long-distance drivers. METHODS: This was a cross-sectional study. Stratified cluster sampling approach was used to select drivers based on if they received annual health screening (AHS) or not (non AHS). We used a structured questionnaire to obtain information and weighted the resulting observations to derive population based estimates. Association between tobacco smoking and socio-demographic factors was explored in multivariate models. RESULTS: 414 male drivers, mean age 43.6 (standard error 0.6) years. Population weighted prevalence of current smoking was 18.9% (95% CI: 14.3-23.4) of all drivers, 6.5% (95% CI: 2.6-10.4) of AHS drivers and 19.5 (95% CI: 14.7-24.2) of non AHS drivers (p<0.001). In multivariate models, having close friends that smoked (OR= 6.36, 95% CI= 2.49 - 16.20) cargo driving (OR= 2.58, 95% CI= 1.29 - 5.15) and lower education levels (OR for post-secondary education vs. primary education or less= 0.17, 95% CI= 0.04 - 0.81) were associated with current smoking. CONCLUSION: Prevalence of tobacco smoking is higher among non AHS compared to AHS drivers. Having close friends that smoked, cargo driving, and lower education levels were associated with current smoking.

Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: a systematic review and modelling study.

BACKGROUND: We have previously estimated that respiratory syncytial virus (RSV) was associated with 22% of all episodes of (severe) acute lower respiratory infection (ALRI) resulting in 55 000 to 199 000 deaths in children younger than 5 years in 2005. In the past 5 years, major research activity on RSV has yielded substantial new data from developing countries. With a considerably expanded dataset from a large international collaboration, we aimed to estimate the global incidence, hospital admission rate, and mortality from RSV-ALRI episodes in young children in 2015. METHODS: We estimated the incidence and hospital admission rate of RSV-associated ALRI (RSV-ALRI) in children younger than 5 years stratified by age and World Bank income regions from a systematic review of studies published between Jan 1, 1995, and Dec 31, 2016, and unpublished data from 76 high quality population-based studies. We estimated the RSV-ALRI incidence for 132 developing countries using a risk factor-based model and 2015 population estimates. We estimated the in-hospital RSV-ALRI mortality by combining in-hospital case fatality ratios with hospital admission estimates from hospital-based (published and unpublished) studies. We also estimated overall RSV-ALRI mortality by identifying studies reporting monthly data for ALRI mortality in the community and RSV activity. FINDINGS: We estimated that globally in 2015, 33·1 million (uncertainty range [UR] 21·6-50·3) episodes of RSV-ALRI, resulted in about 3·2 million (2·7-3·8) hospital admissions, and 59 600 (48 000-74 500) in-hospital deaths in children younger than 5 years. In children younger than 6 months, 1·4 million (UR 1·2-1·7) hospital admissions, and 27 300 (UR 20 700-36 200) in-hospital deaths were due to RSV-ALRI. We also estimated that the overall RSV-ALRI mortality could be as high as 118 200 (UR 94 600-149 400). Incidence and mortality varied substantially from year to year in any given population. INTERPRETATION: Globally, RSV is a common cause of childhood ALRI and a major cause of hospital admissions in young children, resulting in a substantial burden on health-care services. About 45% of hospital admissions and in-hospital deaths due to RSV-ALRI occur in children younger than 6 months. An effective maternal RSV vaccine or monoclonal antibody could have a substantial effect on disease burden in this age group. FUNDING: The Bill & Melinda Gates Foundation.

Real-life effectiveness of 'improved' stoves and clean fuels in reducing PM2.5 and CO: Systematic review and meta-analysis.

BACKGROUND: 2.8 billion people cook with solid fuels, resulting in almost 3 million premature deaths from household air pollution (HAP). To date, no systematic assessment of impacts on HAP of 'improved' stove and clean fuel interventions has been conducted. OBJECTIVE: This systematic review synthesizes evidence for changes in kitchen and personal PM2.5 and carbon monoxide (CO) following introduction of 'improved' solid fuel stoves and cleaner fuels in low- and middle-income countries (LMIC). METHODS: Searches of published and unpublished literature were conducted through databases and specialist websites. Eligible studies reported mean (24 or 48h) small particulate matter (majority PM2.5) and/or CO. Eligible interventions were solid fuel stoves (with/without chimneys, advanced combustion), clean fuels (liquefied petroleum gas, biogas, ethanol, electricity, solar) and mixed. Data extraction and quality appraisal were undertaken using standardized forms, and publication bias assessed. Baseline and post-intervention values and percentage changes were tabulated and weighted averages calculated. Meta-analyses of absolute changes in PM and CO were conducted. RESULTS: Most of the 42 included studies (112 estimates) addressed solid fuel stoves. Large reductions in pooled kitchen PM2.5 (ranging from 41% (29-50%) for advanced combustion stoves to 83% (64-94%) for ethanol stoves), and CO (ranging from 39% (11-55%) for solid fuel stoves without chimneys to 82% (75-95%) for ethanol stoves. Reductions in personal exposure of 55% (19-87%) and 52% (-7-69%) for PM2.5 and CO respectively, were observed for solid fuel stoves with chimneys. For the majority of interventions, post-intervention kitchen PM2.5 levels remained well above WHO air quality guideline (AQG) limit values, although most met the AQG limit value for CO. Subgroup and sensitivity analyses did not substantially alter findings; publication bias was evident for chimney stove interventions but this was restricted to before-and-after studies. CONCLUSIONS: In everyday use in LMIC, neither 'improved' solid fuel stoves nor clean fuels (probably due to neighbourhood contamination) achieve PM2.5 concentrations close to 24-hour AQG limit values. Household energy policy should prioritise community-wide use of clean fuels.

Collecting standardised urban health indicator data at an individual level for adults living in urban areas: methodology from EURO-URHIS 2.

Background: An aim of the EURO-URHIS 2 project was to collect standardised data on urban health indicators (UHIs) relevant to the health of adults resident in European urban areas. This article details development of the survey instruments and methodologies to meet this aim. 32 urban areas from 11 countries conducted the adult surveys. Using a participatory approach, a standardised adult UHI survey questionnaire was developed mainly comprised of previously validated questions, followed by translation and back-translation. An evidence-based survey methodology with extensive training was employed to ensure standardised data collection. Comprehensive UK piloting ensured face validity and investigated the potential for response bias in the surveys. Each urban area distributed 800 questionnaires to age-sex stratified random samples of adults following the survey protocols. Piloting revealed lower response rates in younger males from more deprived areas. Almost 19500 adult UHI questionnaires were returned and entered from participating urban areas. Response rates were generally low but varied across Europe. The participatory approach in development of survey questionnaires and methods using an evidence-based approach and extensive training of partners has ensured comparable UHI data across heterogeneous European contexts. The data provide unique information on health and determinants of health in adults living in European urban areas that could be used to inform urban health policymaking. However, piloting has revealed a concern that non-response bias could lead to under-representation of younger males from more deprived areas. This could affect the generalisability of findings from the adult surveys given the low response rates.

A cleaner burning biomass-fuelled cookstove intervention to prevent pneumonia in children under 5 years old in rural Malawi (the Cooking and Pneumonia Study): a cluster randomised controlled trial.

BACKGROUND: WHO estimates exposure to air pollution from cooking with solid fuels is associated with over 4 million premature deaths worldwide every year including half a million children under the age of 5 years from pneumonia. We hypothesised that replacing open fires with cleaner burning biomass-fuelled cookstoves would reduce pneumonia incidence in young children. METHODS: We did a community-level open cluster randomised controlled trial to compare the effects of a cleaner burning biomass-fuelled cookstove intervention to continuation of open fire cooking on pneumonia in children living in two rural districts, Chikhwawa and Karonga, of Malawi. Clusters were randomly allocated to intervention and control groups using a computer-generated randomisation schedule with stratification by site, distance from health centre, and size of cluster. Within clusters, households with a child under the age of 4·5 years were eligible. Intervention households received two biomass-fuelled cookstoves and a solar panel. The primary outcome was WHO Integrated Management of Childhood Illness (IMCI)-defined pneumonia episodes in children under 5 years of age. Efficacy and safety analyses were by intention to treat. The trial is registered with ISRCTN, number ISRCTN59448623. FINDINGS: We enrolled 10 750 children from 8626 households across 150 clusters between Dec 9, 2013, and Feb 28, 2016. 10 543 children from 8470 households contributed 15 991 child-years of follow-up data to the intention-to-treat analysis. The IMCI pneumonia incidence rate in the intervention group was 15·76 (95% CI 14·89-16·63) per 100 child-years and in the control group 15·58 (95% CI 14·72-16·45) per 100 child-years, with an intervention versus control incidence rate ratio (IRR) of 1·01 (95% CI 0·91-1·13; p=0·80). Cooking-related serious adverse events (burns) were seen in 19 children; nine in the intervention and ten (one death) in the control group (IRR 0·91 [95% CI 0·37-2·23]; p=0·83). INTERPRETATION: We found no evidence that an intervention comprising cleaner burning biomass-fuelled cookstoves reduced the risk of pneumonia in young children in rural Malawi. Effective strategies to reduce the adverse health effects of household air pollution are needed. FUNDING: Medical Research Council, UK Department for International Development, and Wellcome Trust.

Assessment of traditional and improved stove use on household air pollution and personal exposures in rural western Kenya.

BACKGROUND: Over 40% of the world's population relies on solid fuels for heating and cooking. Use of improved biomass cookstoves (ICS) has the potential to reduce household air pollution (HAP). OBJECTIVES: As part of an evaluation to identify ICS for use in Kenya, we collected indoor air and personal air samples to assess differences between traditional cookstoves (TCS) and ICS. METHODS: We conducted a cross-over study in 2012 in two Kenyan villages; up to six different ICS were installed in 45 households during six two-week periods. Forty-eight hour kitchen measurements of fine particulate matter (PM2.5) and carbon monoxide (CO) were collected for the TCS and ICS. Concurrent personal CO measurements were conducted on the mother and one child in each household. We performed descriptive analysis and compared paired measurements between baseline (TCS only) and each ICS. RESULTS: The geometric mean of 48-hour baseline PM2.5 and CO concentrations in the kitchen was 586µg/m3 (95% CI: 460, 747) and 4.9ppm (95% CI: 4.3, 5.5), respectively. For each ICS, the geometric mean kitchen air pollutant concentration was lower than the TCS: median reductions were 38.8% (95% CI: 29.5, 45.2) for PM2.5 and 27.1% (95% CI: 17.4, 40.3) for CO, with statistically significant relationships for four ICS. We also observed a reduction in personal exposures to CO with ICS use. CONCLUSIONS: We observed a reduction in mean 48-hour PM2.5 and CO concentrations compared to the TCS; however, concentrations for both pollutants were still consistently higher than WHO air quality guidelines. Our findings illustrate that ICS tested in real-world settings can reduce exposures to HAP, but implementation of cleaner fuels and related stove technologies may also be necessary to optimize public health benefits.

The prevalence of and factors associated with tobacco smoking behavior among long-distance drivers in Lagos, Nigeria.

BACKGROUND: Factors associated with tobacco smoking are useful in designing tobacco control programs. OBJECTIVES: To estimate the prevalence of and factors associated with tobacco smoking among long-distance drivers. METHODS: A cross-sectional study. Stratified cluster sampling approach was used to select drivers based on if they received annual health screening (AHS) or not (non-AHS). We used a structured questionnaire to obtain information and weighted the resulting observations to derive population based estimates. Association between tobacco smoking and socio-demographic factors was explored in multivariate models. RESULTS: A total of 414 male drivers, with a mean age of 43.6 (standard error 0.6) years were studied. Population weighted prevalence of current smoking was 18.9% (95% CI: 14.3-23.4) all drivers, 6.5% (95% CI: 2.6-10.4) of AHS drivers and 19.5 (95% CI: 14.7-24.2) of non-AHS drivers (p<0.001). In multivariate models, having close friends that smoked (OR= 6.36, 95% CI= 2.49 - 16.20) cargo driving (OR= 2.58, 95% CI= 1.29 - 5.15) and lower education levels (OR for post-secondary education vs. Primary education or less= 0.17, 95% CI= 0.04 - 0.81) were associated with current smoking. CONCLUSION: Prevalence of tobacco smoking is higher among non-AHS compared to AHS drivers. Having close friends that smoked, cargo driving, and lower education levels were associated with current smoking.

Household Air Pollution and Acute Lower Respiratory Infections in Adults: A Systematic Review.

INTRODUCTION: Household air pollution from solid fuel burning kills over 4 million people every year including half a million children from acute lower respiratory infections. Although biologically plausible, it is not clear whether household air pollution is also associated with acute lower respiratory infections in adults. We systematically reviewed the literature on household air pollution and acute lower respiratory infection in adults to identify knowledge gaps and research opportunities. METHODS: Ten bibliographic databases were searched to identify studies of household air pollution and adult acute lower respiratory infection. Data were extracted from eligible studies using standardised forms. RESULTS: From 4617 titles, 513 abstracts and 72 full-text articles were reviewed. Eight studies met the inclusion criteria of which 2 found a significant adjusted increased risk of acute lower respiratory infection, 2 identified a univariate association whilst 4 found no significant association. Study quality was generally limited. Heterogeneity in methods and findings precluded meta-analysis. DISCUSSION: A systematic review of the literature found limited evidence for an association between household air pollution and risk of acute lower respiratory infection in adults. Additional research, with carefully defined exposure and outcome measures, is required to complete the risk profile caused by household air pollution in adults. REGISTRATION NUMBER: CRD42015028042.

Effectiveness of Six Improved Cookstoves in Reducing Household Air Pollution and Their Acceptability in Rural Western Kenya.

BACKGROUND: Household air pollution (HAP) from biomass fuel burning is linked to poor health outcomes. Improved biomass cookstoves (ICS) have the potential to improve HAP. OBJECTIVES: A pre-/post- intervention study assessed the impact of six ICS on indoor air quality and acceptability of ICS to local users in rural Western Kenya. METHODS: We measured mean personal and kitchen level concentrations of particulate matter <2.5µm in diameter (PM2.5, µg/m3) and carbon monoxide (CO, ppm) during the 48-hour period of each ICS use in 45 households. We compared these levels to those observed with traditional 3-stone fire (TSF) use. We assessed ICS acceptability through interviews and focus groups. We evaluated association of stove type, fuel use, and factors related to cooking practices with mean kitchen PM2.5 and CO using multivariable regression. RESULTS: Stove type, exclusive ICS use (vs. concurrent TSF use), and the amount of fuel used were independently associated with kitchen PM2.5 and CO levels. Reductions (95%CI) in mean PM2.5 compared to TSF, ranged by ICS from 11.9% (-2.8-24.5) to 42.3% (32.3-50.8). Reductions in kitchen CO compared to TSF, ranged by ICS from -5.8% (-21.9-8.2) to 34.5% (23.2-44.1). Mean kitchen PM2.5 ranged from 319µg/m3 to 518µg/m3 by ICS. Women thought ICS were easy to use, more efficient, produced less smoke, and cooked faster, compared to TSF. Women also reported limitations for each ICS. CONCLUSIONS: We documented reductions in HAP from ICS compared to TSF. The PM2.5 levels with ICS use were still considerably higher than WHO indoor air quality guidelines. Achieving maximal potential of ICS requires adherence to more exclusive use and addressing user reported ICS limitations.

Lung function in woodsmoke-exposed Guatemalan children following a chimney stove intervention.

RATIONALE: Household air pollution (HAP) from solid fuel combustion is a major contributor to the global burden of disease, with considerable impact from respiratory infections in children. The impact of HAP on lung function is unknown. OBJECTIVES: The Childhood Exposure to Respirable Particulate Matter (CRECER) prospective cohort study followed Guatemalan children who participated in the Randomised Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) trial of a chimney stove intervention to determine the effect of early childhood HAP exposure on growth of lung function. METHODS: RESPIRE households with pregnant women or infant children were randomised to receive a chimney stove at the beginning or at the end of the 18-month trial. During CRECER, a subset of these children, as well as children from households with newly installed stoves, were followed with spirometry beginning at age 5. Biomass smoke exposure was measured using personal carbon monoxide tubes. Two-stage regression models were employed to analyse associations with lung function growth. MEASUREMENTS AND MAIN RESULTS: Longitudinal peak expiratory flow (PEF) and FEV1 data were available for 443 and 437 children, respectively, aged 5-8 (mean follow-up 1.3 years). Decreases in PEF growth of 173 mL/min/year (95% CI -341 to -7) and FEV1 of 44 mL/year (95% CI -91 to 4) were observed with stove installation at 18 months compared with stove installation at birth in analyses adjusted for multiple covariates. No statistically significant associations were observed between personal HAP exposure and lung function. CONCLUSIONS: A significant decrease in PEF growth and a large non-significant decrease in FEV1 growth were observed with later stove installation. Additional studies including longer follow-up and cleaner stoves or fuels are needed.