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Recent years have seen a proliferation of initiatives aimed at enhancing the age-friendliness of urban settings. The World Health Organization's (WHO) global Age-Friendly Cities (AFC) programme has been central to these. Cities seeking to become more age-friendly need reliable ways of assessing their efforts. This article describes an evidence-based evaluation tool for age-friendly initiatives whose development was informed by fieldwork in Liverpool/UK. The tool complements existing assessment frameworks, including those provided by WHO, by paying particular attention to the structures and processes underlying age-friendly initiatives. It reflects the complexity of age-friendliness by reconciling a focus on breadth with detail and depth, and it allows for a highly accessible visual presentation of findings. Using selected examples from Liverpool, the article illustrates how the evaluation tool can be applied to guide policy and practice with an age-friendly focus in different urban contexts. Pilot testing in further settings is underway to refine the tool as a practical method for evaluation and for supporting city-level decision making. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. Methods: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

SUMMARY: Clean cooking has emerged as a major concern for global health and development because of the enormous burden of disease caused by traditional cookstoves and fires. The World Health Organization has developed new indoor air quality guidelines that few homes will be able to achieve without replacing traditional methods with modern clean cooking technologies, including fuels and stoves. However, decades of experience with improved stove programs indicate that the challenge of modernizing cooking in impoverished communities includes a complex, multi-sectoral set of problems that require implementation research. The National Institutes of Health, in partnership with several government agencies and the Global Alliance for Clean Cookstoves, has launched the Clean Cooking Implementation Science Network that aims to address this issue. In this article, our focus is on building a knowledge base to accelerate scale-up and sustained use of the cleanest technologies in low- and middle-income countries. Implementation science provides a variety of analytical and planning tools to enhance effectiveness of clinical and public health interventions. These tools are being integrated with a growing body of knowledge and new research projects to yield new methods, consensus tools, and an evidence base to accelerate improvements in health promised by the renewed agenda of clean cooking. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: COPD is the third most frequent cause of death globally, with much of this burden attributable to household biomass smoke exposure in developing countries. As biomass smoke exposure is also associated with cardiovascular disease, lower respiratory infection, lung cancer, and cataracts, it presents an important target for public health intervention.Methods: Lung function in Guatemalan women exposed to wood smoke from open fires was measured throughout the Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) stove intervention trial and continued during the Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter (CRECER) cohort study. In RESPIRE, early stove households received a chimney woodstove at the beginning of the 18-month trial, and delayed stove households received a stove at trial completion. Personal exposure to wood smoke was assessed with exhaled breath carbon monoxide (CO) and personal CO tubes. Change in lung function between intervention groups and as a function of wood smoke exposure was assessed using random effects models.Results: Of 306 women participating in both studies, acceptable spirometry was collected in 129 early stove and 136 delayed stove households (n = 265), with a mean follow-up of 5.6 years. Despite reduced wood smoke exposures in early stove households, there were no significant differences in any of the measured spirometric variables during the study period (FEV1, FVC, FEV1/FVC ratio, and annual change) after adjustment for confounding.Conclusions: In these young Guatemalan women, there was no association between lung function and early randomization to a chimney stove or personal wood smoke exposure. Future stove intervention trials should incorporate cleaner stoves, longer follow-up, or potentially susceptible groups to identify meaningful differences in lung function. [ABSTRACT FROM AUTHOR]

Background Around 2.4 billion people use traditional biomass fuels for household cooking or heating. In 2006, the International Agency for Research on Cancer (IARC) concluded emissions from household coal combustion are a Group 1 carcinogen, while those from biomass were categorised as 2A due to epidemiologic limitations. This review updates the epidemiologic evidence and provides risk estimates for the 2010 Global Burden of Disease study. Methods Searches were conducted of 10 databases to July 2012 for studies of clinically diagnosed or pathologically confirmed lung cancer associated with household biomass use for cooking and/or heating. Findings Fourteen eligible studies of biomass cooking or heating were identified: 13 had independent estimates (12 cooking only), all were case-control designs and provided 8221 cases and 11 342 controls. The ORs for lung cancer risk with biomass for cooking and/or heating were OR 1.17 (95% CI 1.01 to 1.37) overall, and 1.15 (95% CI 0.97 to 1.37) for cooking only. Publication bias was not detected, but more than half the studies did not explicitly describe a clean reference category. Sensitivity analyses restricted to studies with adequate adjustment and a clean reference category found ORs of 1.21 (95% CI 1.05 to 1.39) for men (two reports, compiling five studies) and 1.95 (95% CI 1.16 to 3.27) for women (five reports, compiling eight studies). Exposure-response evidence was seen for men, and higher risk for women in developing compared with developed countries, consistent with higher exposures in the former. Conclusions There is now stronger evidence for biomass fuel use causing lung cancer, but future studies need better exposure assessment to strengthen exposure- response evidence. [ABSTRACT FROM AUTHOR]

Background: With 40% of the world's population relying on solid fuel, household air pollution (HAP) represents a major preventable risk factor for COPD (chronic obstructive pulmonary disease). Meta-analyses have confirmed this relationship; however, constituent studies are observational, with virtually none measuring exposure directly. Objectives: We estimated associations between HAP exposure and respiratory symptoms and lung function in young, nonsmoking women in rural Guatemala, using measured carbon monoxide (CO) concentrations in exhaled breath and personal air to assess exposure. Methods: The Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) Guatemala study was a trial comparing respiratory outcomes among 504 women using improved chimney stoves versus traditional cookstoves. The present analysis included 456 women with data from postintervention surveys including interviews at 6, 12, and 18 months (respiratory symptoms) and spirometry and CO (ppm) in exhaled breath measurements. Personal CO was measured using passive diffusion tubes at variable times during the study. Associations between CO concentrations and respiratory health were estimated using random intercept regression models. Results: Respiratory symptoms (cough, phlegm, wheeze, or chest tightness) during the previous 6 months were positively associated with breath CO measured at the same time of symptom reporting and with average personal CO concentrations during the follow-up period. CO in exhaled breath at the same time as spirometry was associated with lower lung function [average reduction in FEV1 (forced expiratory volume in 1 sec) for a 10% increase in CO was 3.33 mL (95% CI: -0.86, -5.81)]. Lung function measures were not significantly associated with average postintervention personal CO concentrations. Conclusions: Our results provide further support for the effects of HAP exposures on airway inflammation. Further longitudinal research modeling continuous exposure to particulate matter against lung function will help us understand more fully the impact of HAP on COPD. Citation: Pope D, Diaz E, Smith-Sivertsen T, Lie RT, Bakke P, Balmes JR, Smith KR, Bruce NG. 2015. Exposure to household air pollution from wood combustion and association with respiratory symptoms and lung function in nonsmoking women: results from the RESPIRE Trial, Guatemala. Environ Health Perspect 123:285-292; http://dx.doi.org/10.1289/ehp.1408200 [ABSTRACT FROM AUTHOR]

The challenge of promoting access to clean and efficient household energy for cooking and heating is a critical issue facing low- and middle-income countries today. Along with clean fuels, improved cookstoves (ICSs) continue to play an important part in efforts to reduce the 4 million annual premature deaths attributed to household air pollution. Although a range of ICSs are available, there is little empirical evidence on appropriate behavior change approaches to inform adoption and sustained used at scale. Specifically, evaluations using either quantitative or qualitative methods provide an incomplete picture of the challenges in facilitating ICS adoption. This article examines how studies that use the strengths of both these approaches can offer important insights into behavior change in relation to ICS uptake and scale-up. Epistemological approaches, study design frameworks, methods of data collection, analytical approaches, and issues of validity and reliability in the context of mixed methods ICS research are examined, and the article presents an example study design from an evaluation study in Kenya incorporating a nested approach and a convergent case oriented design. The authors discuss the benefits and methodological challenges of mixed-methods approaches in the context of researching behavior change and ICS use recognizing that such methods represent relatively uncharted territory. The authors propose that more published examples are needed to provide frameworks for other researchers seeking to apply mixed methods in this context and suggest a comprehensive research agenda is required that incorporates integrated mixed-methods approaches, to provide best evidence for future scale-up. [ABSTRACT FROM PUBLISHER]

BACKGROUND: Estimating the burden of disease attributable to long-term exposure to fine particulate matter (PM2.5) in ambient air requires knowledge of both the shape and magnitude of the relative risk (RR) function. However, adequate direct evidence to identify the shape of the mortality RR functions at the high ambient concentrations observed in many places in the world is lacking. OBJECTIVE: We developed RR functions over the entire global exposure range for causes of mortality in adults: ischemic heart disease (IHD), cerebrovascular disease (stroke), chronic obstructive pulmonary disease (COPD), and lung cancer (LC). We also developed RR functions for the incidence of acute lower respiratory infection (ALRI) that can be used to estimate mortality and lost-years of healthy life in children < 5 years of age. METHODS: We fit an integrated exposure-response (IER) model by integrating available RR information from studies of ambient air pollution (AAP), second hand tobacco smoke, household solid cooking fuel, and active smoking (AS). AS exposures were converted to estimated annual PM2.5 exposure equivalents using inhaled doses of particle mass. We derived population attributable fractions (PAFs) for every country based on estimated worldwide ambient PM2.5 concentrations. Results: The IER model was a superior predictor of RR compared with seven other forms previously used in burden assessments. The percent PAF attributable to AAP exposure varied among countries from 2 to 41 for IHD, 1 to 43 for stroke, < 1 to 21 for COPD, < 1 to 25 for LC, and < 1 to 38 for ALRI. CONCLUSIONS: We developed a fine particulate mass-based RR model that covered the global range of exposure by integrating RR information from different combustion types that generate emissions of particulate matter. The model can be updated as new RR information becomes available. [ABSTRACT FROM AUTHOR]

Objectives. We identified barriers to care seeking for pneumonia and diarrhea among rural Guatemalan children. Methods. A population-based survey was conducted twice from 2008 to 2009 among 1605 households with children younger than 5 years. A 14-day calendar recorded episodes of carer-reported pneumonia (n = 364) and diarrhea (n = 481), and formal (health services, public, private) and informal (neighbors, traditional, local shops, pharmacies) care seeking. Results. Formal care was sought for nearly half of severe pneumonias but only for 27% within 2 days of onset, with 31% and 18%, respectively, for severe diarrhea. In multivariable analysis, factors independently associated with formal care seeking were knowing the Community Emergency Plan, mother's perception of illness severity, recognition of World Health Organization danger signs, distance from the health center, and having someone to care for family in an emergency. Conclusions. Proximal factors associated with recognizing need for care were important in determining formal care, and were strongly linked to social determinants. In addition to specific action by the health system with an enhanced community health worker role, a systems approach can help ensure barriers are addressed among poorer and more remote homes. [ABSTRACT FROM AUTHOR]

In the Comparative Risk Assessment (CRA) done as part of the Global Burden of Disease project (GBD-2010), the global and regional burdens of household air pollution (HAP) due to the use of solid cookfuels, were estimated along with 60+ other risk factors. This article describes how the HAP CRA was framed; how global HAP exposures were modeled; how diseases were judged to have sufficient evidence for inclusion; and how meta-analyses and exposure-response modeling were done to estimate relative risks. We explore relationships with the other air pollution risk factors: ambient air pollution, smoking, and secondhand smoke. We conclude with sensitivity analyses to illustrate some of the major uncertainties and recommendations for future work. We estimate that in 2010 HAP was responsible for 3.9 million premature deaths and ∼4.8% of lost healthy life years (DALYs), ranking it highest among environmental risk factors examined and one of the major risk factors of any type globally. [ABSTRACT FROM AUTHOR]

Background: More than two-fifths of the world’s population uses solid fuels, mostly biomass, for cooking. The resulting biomass smoke exposure is a major cause of chronic obstructive pulmonary disease (COPD) among women in developing countries. Objective: To assess whether lower woodsmoke exposure from use of a stove with a chimney, compared to open fires, is associated with lower markers of airway inflammation in young women. Design: We carried out a cross-sectional analysis on a sub-cohort of participants enrolled in a randomized controlled trial in rural Guatemala, RESPIRE. Participants: We recruited 45 indigenous women at the end of the 18-month trial; 19 women who had been using the chimney stove for 18–24 months and 26 women still using open fires. Measurements: We obtained spirometry and induced sputum for cell counts, gene expression of IL-8, TNF-α, MMP-9 and 12, and protein concentrations of IL-8, myeloperoxidase and fibronectin. Exhaled carbon monoxide (CO) and 48-hr personal CO tubes were measured to assess smoke exposure. Results: MMP-9 gene expression was significantly lower in women using chimney stoves. Higher exhaled CO concentrations were significantly associated with higher gene expression of IL-8, TNF-α, and MMP-9. Higher 48-hr personal CO concentrations were associated with higher gene expression of IL-8, TNF- α, MMP-9 and MMP-12; reaching statistical significance for MMP-9 and MMP-12. Conclusions: Compared to using an open wood fire for cooking, use of a chimney stove was associated with lower gene expression of MMP-9, a potential mediator of airway remodeling. Among all participants, indoor biomass smoke exposure was associated with higher gene expression of multiple mediators of airway inflammation and remodeling; these mechanisms may explain some of the observed association between prolonged biomass smoke exposure and COPD. [ABSTRACT FROM AUTHOR]

Background: Globally, 2.8 billion people rely on household solid fuels. Reducing the resulting adverse health, environmental, and development consequences will involve transitioning through a mix of clean fuels and improved solid fuel stoves (IS) of demonstrable effectiveness. To date, achieving uptake of IS has presented significant challenges. Objectives: We performed a systematic review of factors that enable or limit large-scale uptake of IS in low- and middle-income countries. Methods: We conducted systematic searches through multidisciplinary databases, specialist websites, and consulting experts. The review drew on qualitative, quantitative, and case studies and used standardized methods for screening, data extraction, critical appraisal, and synthesis. We summarized our findings as 'factors' relating to one of seven domains-fuel and technology characteristics; household and setting characteristics; knowledge and perceptions; finance, tax, and subsidy aspects; market development; regulation, legislation, and standards; programmatic and policy mechanisms- and also recorded issues that impacted equity. Results: We identified 31 factors influencing uptake from 57 studies conducted in Asia, Africa, and Latin America. All domains matter. Although factors such as offering technologies that meet household needs and save fuel, user training and support, effective financing, and facilitative government action appear to be critical, none guarantee success: All factors can be influential, depending on context. The nature of available evidence did not permit further prioritization. Conclusions: Achieving adoption and sustained use of IS at a large scale requires that all factors, spanning household/community and program/societal levels, be assessed and supported by policy. We propose a planning tool that would aid this process and suggest further research to incorporate an evaluation of effectiveness. [ABSTRACT FROM AUTHOR]

Background: Globally, 2.8 billion people rely on household solid fuels. Reducing the resulting adverse health, environmental, and development consequences will involve transitioning through a mix of clean fuels and improved solid fuel stoves (IS) of demonstrable effectiveness. To date, achieving uptake of IS has presented significant challenges. Objectives: We performed a systematic review of factors that enable or limit large-scale uptake of IS in low- and middle-income countries. Methods: We conducted systematic searches through multidisciplinary databases, specialist websites, and consulting experts. The review drew on qualitative, quantitative, and case studies and used standardized methods for screening, data extraction, critical appraisal, and synthesis. We summarized our findings as "factors" relating to one of seven domains-fuel and technology characteristics; household and setting characteristics; knowledge and perceptions; finance, tax, and subsidy aspects; market development; regulation, legislation, and standards; programmatic and policy mechanisms- and also recorded issues that impacted equity. Results: We identified 31 factors influencing uptake from 57 studies conducted in Asia, Africa, and Latin America. All domains matter. Although factors such as offering technologies that meet household needs and save fuel, user training and support, effective financing, and facilitative government action appear to be critical, none guarantee success: All factors can be influential, depending on context. The nature of available evidence did not permit further prioritization. Conclusions: Achieving adoption and sustained use of IS at a large scale requires that all factors, spanning household/community and program/societal levels, be assessed and supported by policy. We propose a planning tool that would aid this process and suggest further research to incorporate an evaluation of effectiveness. [ABSTRACT FROM AUTHOR]

In the Comparative Risk Assessment (CRA) done as part of the Global Burden of Disease project (GBD-2010), the global and regional burdens of household air pollution (HAP) due to the use of solid cookfuels, were estimated along with 60+ other risk factors. This article describes how the HAP CRA was framed; how global HAP exposures were modeled; how diseases were judged to have sufficient evidence for inclusion; and how meta-analyses and exposure-response modeling were done to estimate relative risks. We explore relationships with the other air pollution risk factors: ambient air pollution, smoking, and secondhand smoke. We conclude with sensitivity analyses to illustrate some of the major uncertainties and recommendations for future work. We estimate that in 2010 HAP was responsible for 3.9 million premature deaths and ∼4.8% of lost healthy life years (DALYs), ranking it highest among environmental risk factors examined and one of the major risk factors of any type globally. [ABSTRACT FROM AUTHOR]

In the Comparative Risk Assessment (CRA) done as part of the Global Burden of Disease project (GBD-2010), the global and regional burdens of household air pollution (HAP) due to the use of solid cookfuels, were estimated along with 60+ other risk factors. This article describes how the HAP CRA was framed; how global HAP exposures were modeled; how diseases were judged to have sufficient evidence for inclusion; and how meta-analyses and exposure-response modeling were done to estimate relative risks. We explore relationships with the other air pollution risk factors: ambient air pollution, smoking, and secondhand smoke. We conclude with sensitivity analyses to illustrate some of the major uncertainties and recommendations for future work. We estimate that in 2010 HAP was responsible for 3.9 million premature deaths and ∼4.8% of lost healthy life years (DALYs), ranking it highest among environmental risk factors examined and one of the major risk factors of any type globally. [ABSTRACT FROM AUTHOR]

Background: Exposure to household air pollution (HAP) from cooking with solid fuels affects 2.8 billion people in developing countries, including children and pregnant women. The aim of this review is to propose intervention estimates for child survival outcomes linked to HAP. Methods: Systematic reviews with meta-analysis were conducted for ages 0-59 months, for child pneumonia, adverse pregnancy outcomes, stunting and all-cause mortality. Evidence for each outcome was assessed against Bradford-Hill viewpoints, and GRADE used for certainty about intervention effect size for which all odds ratios (OR) are presented as protective effects. Results: Reviews found evidence linking HAP exposure with child ALRI, low birth weight (LBW), stillbirth, preterm birth, stunting and all-cause mortality. Most studies were observational and rated low/very low in GRADE despite strong causal evidence for some outcomes; only one randomised trial was eligible.Intervention effect (OR) estimates of 0.64 (95% CI: 0.55, 0.75) for ALRI, 0.71 (0.65, 0.79) for LBW and 0.66 (0.54, 0.81) for stillbirth are proposed, specific outcomes for which causal evidence was sufficient. Exposure-response evidence suggests this is a conservative estimate for ALRI risk reduction expected with sustained, low exposure. Statistically significant protective ORs were also found for stunting [OR=0.79 (0.70, 0.89)], and in one study of pre-term birth [OR=0.70 (0.54, 0.90)], indicating these outcomes would also likely be reduced. Five studies of all-cause mortality had an OR of 0.79 (0.70, 0.89), but heterogenity precludes a reliable estimate for mortality impact. Although interventions including clean fuels and improved solid fuel stoves are available and can deliver low exposure levels, significant challenges remain in achieving sustained use at scale among low-income households. Conclusions: Reducing exposure to HAP could substantially reduce the risk of several child survival outcomes, including fatal pneumonia, and the proposed effects could be achieved by interventions delivering low exposures. Larger impacts are anticipated if WHO air quality guidelines are met. To achieve these benefits, clean fuels should be adopted where possible, and for other households the most effective solid fuel stoves promoted. To strengthen evidence, new studies with thorough exposure assessment are required, along with evaluation of the longer-term acceptance and impacts of interventions. [ABSTRACT FROM AUTHOR]

There is major untapped potential to improve health in low-income communities through improved housing design, fittings, materials and construction. Adverse effects on health from inadequate housing can occur through a range of mechanisms, both direct and indirect, including as a result of extreme weather, household air pollution, injuries or burns, the ingress of disease vectors and lack of clean water and sanitation. Collaborative action between public health professionals and those involved in developing formal and informal housing could advance both health and development by addressing risk factors for a range of adverse health outcomes. Potential trade-offs between design features which may reduce the risk of some adverse outcomes whilst increasing the risk of others must be explicitly considered. [ABSTRACT FROM AUTHOR]

Background: Exposure to household air pollution from cooking with solid fuels in simple stoves is a major health risk. Modeling reliable estimates of solid fuel use is needed for monitoring trends and informing policy. Objectives: In order to revise the disease burden attributed to household air pollution for the Global Burden of Disease 2010 project and for international reporting purposes, we estimated annual trends in the world population using solid fuels. Methods: We developed a multilevel model based on national survey data on primary cooking fuel. Results: The proportion of households relying mainly on solid fuels for cooking has decreased from 62% (95% CI: 58, 66%) to 41% (95% CI: 37, 44%) between 1980 and 2010. Yet because of population growth, the actual number of persons exposed has remained stable at around 2.8 billion during three decades. Solid fuel use is most prevalent in Africa and Southeast Asia where > 60% of households cook with solid fuels. In other regions, primary solid fuel use ranges from 46% in the Western Pacific, to 35% in the Eastern Mediterranean and < 20% in the Americas and Europe. Conclusion: Multilevel modeling is a suitable technique for deriving reliable solid-fuel use estimates. Worldwide, the proportion of households cooking mainly with solid fuels is decreasing. The absolute number of persons using solid fuels, however, has remained steady globally and is increasing in some regions. Surveys require enhancement to better capture the health implications of new technologies and multiple fuel use. [ABSTRACT FROM AUTHOR]

This article discusses an effort aimed at addressing the gaps in the current evidence on the health effects of household air pollution (HAP) and unsafe stoves and at identifying critical considerations for effective implementation. It is noted that HAP from solid fuel combustion is the leading environmental cause of death and disability in the world. It is also suggested that researchers partner with organizations and governments to evaluate impacts of improved stove and fuel programs.

Household air pollution (HAP) due to solid fuel use is a major public health threat in low-income countries. Most health effects are thought to be related to exposure to the fine particulate matter (PM) component of HAP, but it is currently impractical to measure personal exposure to PM in large studies. Carbon monoxide (CO) has been shown in cross-sectional analyses to be a reliable surrogate for particles<2.5 µm in diameter (PM2.5) in kitchens where wood-burning cookfires are a dominant source, but it is unknown whether a similar PM2.5-CO relationship exists for personal exposures longitudinally. We repeatedly measured (216 measures, 116 women) 24-hour personal PM2.5 (median [IQR] = 0.11 [0.05, 0.21] mg/m3) and CO (median [IQR] = 1.18 [0.50, 2.37] mg/m3) among women cooking over open woodfires or chimney woodstoves in Guatemala. Pollution measures were natural-log transformed for analyses. In linear mixed effects models with random subject intercepts, we found that personal CO explained 78% of between-subject variance in personal PM2.5. We did not see a difference in slope by stove type. This work provides evidence that in settings where there is a dominant source of biomass combustion, repeated measures of personal CO can be used as a reliable surrogate for an individual's PM2.5 exposure. This finding has important implications for the feasibility of reliably estimating long-term (months to years) PM2.5 exposure in large-scale epidemiological and intervention studies of HAP. [ABSTRACT FROM AUTHOR]

Background: There has been little rigorous economic analysis of the relationship between asthma and improved housing.Aim: To evaluate the cost-effectiveness of installing ventilation systems, and central heating if necessary, in homes of children with 'moderate' or 'severe' asthma.Design and Setting: An incremental cost-effectiveness analysis alongside a pragmatic randomised controlled trial of a tailored package of housing modifications designed to improve ventilation and household heating in homes within Wrexham County Borough, Wales, UK.Method: A total of 177 children aged between 5 and 14 years, identified from general practice registers, were studied. Parents reported on the quality of life of their children over a 12-month period. General practices reported on health-service resources used by those children, and their asthma-related prescriptions, over the same period.Results: The tailored package shifted 17% of children in the intervention group from 'severe' to 'moderate' asthma, compared with a 3% shift in the control group. The mean cost of these modifications was £1718 per child treated or £12300 per child shifted from 'severe' to 'moderate'. Healthcare costs over 12 months following randomisation did not differ significantly between intervention and control groups. Bootstrapping gave an incremental cost-effectiveness ratio (ICER) of £234 per point improvement on the 100-point PedsQL™ asthma-specific scale, with 95% confidence interval (CI) = £140 to £590. The ICER fell to £165 (95% CI = £84 to £424) for children with 'severe' asthma.Conclusion: This novel and pragmatic trial, with integrated economic evaluation, reported that tailored improvement of the housing of children with moderate to severe asthma is likely to be a cost-effective use of public resources. This is a rare example of evidence for collaboration between local government and the NHS. [ABSTRACT FROM AUTHOR]

Background: Few robust studies have tested whether enhancing housing also improves health.Aim: To evaluate the effectiveness of installing ventilation systems, and central heating where necessary, in the homes of children with moderate or severe asthma.Design and Setting: Pragmatic randomised controlled trial (RCT) in homes within Wrexham County Borough, Wales, UK.Method: A pragmatic RCT was carried out, of a tailored package of housing improvements providing adequate ventilation and temperature, following inspection by a housing officer. One hundred and ninety-two children with asthma aged 5 to 14 years, identified from general practice registers, were randomised to receive this package, either immediately or a year after recruitment. At baseline, and after 4 and 12 months, parents reported their child's asthma-specific and generic quality of life, and days off school.Results: The package improved parent-reported asthma-specific quality of life significantly at both 4 and 12 months. At 12 months, this showed an adjusted mean difference between groups of 7.1 points (95% confidence interval [CI] = 2.8 to 11.4, P= 0.001): a moderate standardised effect size of 0.42. The generic quality-of-life scale showed reported physical problems were significantly reduced at 4 months, but not quite at 12 months, when the mean difference was 4.5 (95% CI = -0.2 to 9.1, P= 0.061). The improvement in psychosocial quality of life at 12 months was not significant, with a mean difference of 2.2 (95% CI = -1.9 to 6.4, P= 0.292). Parent-reported school attendance improved, but not significantly.Conclusion: This novel and pragmatic trial, with integrated economic evaluation, found that tailored improvement of the housing of children with moderate to severe asthma significantly increases parent-reported asthma-related quality of life and reduces physical problems. Collaborative housing initiatives have potential to improve health. [ABSTRACT FROM AUTHOR]

Background: A growing body of evidence indicates a relationship between household indoor air pollution from cooking fires and adverse neonatal outcomes, such as low birth weight (LBW), in resource-poor countries. Objective: We examined the effect of reduced wood smoke exposure in pregnancy on LBW of Guatemalan infants in RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects). Methods: Pregnant women (n = 266) either received a chimney stove (intervention) or continued to cook over an open fire (control). Between October 2002 and December 2004 we weighed 174 eligible infants (69 to mothers who used a chimney stove and 105 to mothers who used an open fire during pregnancy) within 48 hr of birth. Multivariate linear regression and adjusted odds ratios (ORs) were used to estimate differences in birth weight and LBW (< 2,500 g) associated with chimney- stove versus open-fire use during pregnancy. Results: Pregnant women using chimney stoves had a 39% reduction in mean exposure to carbon monoxide compared with those using open fires. LBW prevalence was high at 22.4%. On average, infants born to mothers who used a stove weighed 89 g more [95% confidence interval (CI), -27 to 204 g] than infants whose mothers used open fires after adjusting for maternal height, diastolic blood pressure, gravidity, and season of birth. The adjusted OR for LBW was 0.74 (95% CI, 0.33-1.66) among infants of stove users compared with open-fire users. Average birth weight was 296 g higher (95% CI, 109-482 g) in infants born during the cold season (after harvest) than in other infants; this unanticipated finding may reflect the role of maternal nutrition on birth weight in an impoverished region. Conclusions: A chimney stove reduced wood smoke exposures and was associated with reduced LBW occurrence. Although not statistically significant, the estimated effect was consistent with previous studies. [ABSTRACT FROM AUTHOR]

Background Emissions from household coal combustion associated with cooking and heating are an important public health issue, particularly in China where hundreds of millions of people are exposed. Although coal emissions are a known human carcinogen, there is still uncertainty about the level of risk for lung and other cancers.Methods We performed a meta-analysis on 25 case–control studies (10 142 cases and 13 416 controls) to summarize the association between household coal use and lung cancer risk, and to explore the effect modification of this association by geographical location.Results Using random-effects models, household coal use was found to be associated with lung cancer risk among all studies throughout the world [odds ratio (OR) = 2.15; 95% confidence interval (CI) = 1.61–2.89, Nstudies = 25], and particularly among those studies carried out in mainland China and Taiwan (OR = 2.27; 95% CI = 1.65–3.12, Nstudies = 20). Stratification by regions of mainland China and Taiwan found a variation in effects across the regions, with south/southeastern (OR = 3.27; 95% CI = 1.27–8.42, Nstudies = 3) and southwestern China (OR = 2.98; 95% CI = 1.18–7.53, Nstudies = 3) experiencing the highest risk. The elevated risk associated with coal use throughout Asia was also observed when stratifying studies by gender, smoking status, sample size, design (population vs hospital case–control) and publication language. No significant publication bias was found (pBegg’s = 0.15).Conclusions Our results provide evidence that although the carcinogenic effect of coal use varies by location, coals from many locations exhibit elevated lung cancer risks. [ABSTRACT FROM AUTHOR]

During the first randomized intervention trial (RESPIRE: Randomized Exposure Study of Pollution Indoors and Respiratory Effects) in air pollution epidemiology, we pioneered application of passive carbon monoxide (CO) diffusion tubes to measure long-term personal exposures to woodsmoke. Here we report on the protocols and validations of the method, trends in personal exposure for mothers and their young children, and the efficacy of the introduced improved chimney stove in reducing personal exposures and kitchen concentrations. Passive diffusion tubes originally developed for industrial hygiene applications were deployed on a quarterly basis to measure 48-hour integrated personal carbon monoxide exposures among 515 children 0-18 months of age and 532 mothers aged 15-55 years and area samples in a subsample of 77 kitchens, in households randomized into control and intervention groups. Instrument comparisons among types of passive diffusion tubes and against a continuous electrochemical CO monitor indicated that tubes responded nonlinearly to CO, and regression calibration was used to reduce this bias. Before stove introduction, the baseline arithmetic (geometric) mean 48-h child (n=270), mother (n=529) and kitchen (n=65) levels were, respectively, 3.4 (2.8), 3.4 (2.8) and 10.2 (8.4) p.p.m. The between-group analysis of the 3355 post-baseline measurements found CO levels to be significantly lower among the intervention group during the trial period: kitchen levels: −90%; mothers: −61%; and children: −52% in geometric means. No significant deterioration in stove effect was observed over the 18 months of surveillance. The reliability of these findings is strengthened by the large sample size made feasible by these unobtrusive and inexpensive tubes, measurement error reduction through instrument calibration, and a randomized, longitudinal study design. These results from the first randomized trial of improved household energy technology in a developing country and demonstrate that a simple chimney stove can substantially reduce chronic exposures to harmful indoor air pollutants among women and infants. [ABSTRACT FROM AUTHOR]

Exposure to indoor air pollution from solid fuel use (IAP) has been linked to approximately 1.5 million annual deaths (World Health Organization (http://www.who.int/indoorair/publications/fuelforlife/en/index.html)) due to acute lower respiratory infections in children <5 years of age and chronic obstructive lung disease and lung cancer in adults. Emerging evidence suggests that IAP increases the risk of other conditions, including adverse pregnancy outcomes. To establish the relation of IAP with birth weight and stillbirth, systematic reviews with meta-analyses were conducted. Studies reporting outcomes of mean birth weight, percentage of low birth weight (LBW; <2,500 g), and/or stillbirth and assessing IAP were identified. Five LBW studies (of 982) and 3 stillbirth studies (of 171) met inclusion criteria for the reviews. Fixed-effect meta-analyses (I2 = 0%) found that IAP was associated with increased risk of percentage LBW (odds ratio = 1.38, 95% confidence interval: 1.25, 1.52) and stillbirth (odds ratio = 1.51, 95% confidence interval: 1.23, 1.85) and reduced mean birth weight (−95.6 g, 95% confidence interval: −68.5, −124.7). Evidence from secondhand smoke, ambient air pollution, and animal studies—and suggested plausible mechanisms—substantiate these associations. Because a majority of pregnant women in developing countries, where rates of LBW and stillbirth are high, are heavily exposed to IAP, increased relative risk translates into substantial population attributable risks of 21% (LBW) and 26% (stillbirth). [ABSTRACT FROM PUBLISHER]