***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Diarrhoea and respiratory infections remain the biggest killers of children under 5 years in developing countries . We conducted a 5-month household r and omised controlled trial among 566 households in rural Rw and a to assess uptake , compliance and impact on environmental exposures of a combined intervention delivering high-performance water filters and improved stoves for free . Compliance was measured monthly by self-report and spot-check observations . Semi-continuous 24-h PM2.5 monitoring of the cooking area was conducted in a r and om sub sample of 121 households to assess household air pollution  , while sample s of drinking water from all households were collected monthly to assess the levels of thermotolerant coliforms . Adoption was generally high , with most householders reporting the filters as their primary source of drinking water and the intervention stoves as their primary cooking stove . However , some householders continued to drink untreated water and most continued to cook on traditional stoves . The intervention was associated with a 97.5 % reduction in mean faecal indicator bacteria ( Williams means 0.5 vs. 20.2 TTC/100 mL , p<0.001 ) and a median reduction of 48 % of 24-h PM2.5 concentrations in the cooking area ( p = 0.005 ) . Further studies to increase compliance should be undertaken to better inform large-scale interventions . Trial registration : Clinical trials.gov ; NCT01882777 ; http:// clinical trials.gov/ct2/ results ? term = NCT01882777 & Search = Background Acute lower respiratory infections ( ALRI ) are a leading cause of death among children . Low birthweight is prevalent in South Asia and associated with increased risks of mortality , and morbidity , high levels of indoor household air pollution caused by open burning of biomass fuels are common and associated with high rates of ALRI and low birthweight . Alternative stove design s that burn biomass fuel more efficiently have been proposed as one method for reducing these high exposures and lowering rates of these disorders . We design ed two r and omized trials to test this hypothesis . Methods / design We conducted a pair of community-based , r and omized trials of  alternative cookstove installation in a rural district in southern Nepal . Phase one was a cluster r and omized , modified step-wedge design using an alternative biomass stove with a chimney . A pre-installation period of morbidity assessment and household environmental assessment was conducted for six months in all households . This was followed by a one year step-wedge phase with 12 monthly steps for clusters of households to receive the alternative stove . The timing of alternative stove introduction was r and omized . This step-wedge phase was followed in all households by another six month follow-up phase . Eligibility criteria for phase one included household informed consent , the presence of a married woman of reproductive age ( 15–30 yrs ) or a child < 36 months . Children were followed until 36 months of age or the end of the trial . Pregnancies were identified and followed until completion or end of the trial . Phase two was an individually r and omized trial of the same alternative biomass stove versus liquid propane gas stove in a subset of households that participated in phase one . Follow-up for phase two was 12 months following stove installation . Eligibility criteria included the same components as phase one except children were only enrolled for morbidity follow-up if they were less than 24 months . The primary outcomes included : incidence of ALRI in children and birthweight . Discussion We presented the design and methods of two r and omized trials of alternative cookstoves on rates of ALRI and birthweight . Trial registration Clinical trials.gov ( NCT00786877 , Nov. 5 , 2008 ) During the first r and omized intervention trial ( RESPIRE : R and omized 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 protocol s 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 sample s in a sub sample of 77 kitchens , in households r and omized 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 r and omized , longitudinal study design . These results from the first r and omized 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 Background : Cooking with biomass fuels on open fires results in exposure to health-damaging pollutants such as carbon monoxide ( CO ) , polycyclic aromatic hydrocarbons ( PAHs ) , and particulate matter . Objective : We compared CO exposures and urinary PAH biomarkers pre- and postintervention with an improved biomass stove , the Patsari stove . Methods : In a sub sample of 63 women participating in a r and omized controlled trial in central Mexico , we measured personal CO exposure for 8 hr during the day using continuous monitors and passive sample rs . In addition , first-morning urine sample s obtained the next day were analyzed for monohydroxylated PAH metabolites by gas chromatography/isotope dilution/high-resolution mass spectrometry . Exposure data were collected during the use of an open fire ( preintervention ) and after installation of the improved stove ( postintervention ) for 47 women , enabling paired comparisons . Results : Median pre- and postintervention values were 4 and 1 ppm for continuous personal CO and 3 and 1 ppm for passive sample r CO , respectively . Postintervention measurements indicated an average reduction of 42 % for hydroxylated metabolites of naphthalene , fluorene , phenanthrene , and pyrene on a whole-weight concentration basis ( micrograms per liter of urine ) , and a 34 % reduction on a creatinine-adjusted basis ( micrograms per gram of creatinine ) . Pre- and postintervention geometric mean values for 1-hydroxypyrene were 3.2 and 2.0 μg/g creatinine , respectively . Conclusion : Use of the Patsari stove significantly reduced CO and  PAH exposures in women . However , levels of many PAH biomarkers remained higher than those reported among smokers 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 re source -poor countries . Objective : We examined the effect of reduced wood smoke exposure in pregnancy on LBW  of Guatemalan infants in RESPIRE ( R and omized 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 Background Household air pollution exposure is a major health risk , but vali date d interventions remain elusive . Methods / Design The Ghana R and omized Air Pollution and Health Study ( GRAPHS ) is a cluster-r and omized trial that evaluates the efficacy of clean fuels ( liquefied petroleum gas , or LPG ) and efficient biomass cookstoves in the Brong-Ahafo region of central Ghana . We recruit pregnant women into LPG , efficient cookstove , and control arms  and track birth weight and physician-assessed severe pneumonia incidence in the first year of life . A woman is eligible to participate if she is in the first or second trimester of pregnancy and carrying a live singleton fetus , if she is the primary cook , and if she does not smoke . We hypothesize that babies born to intervention mothers will weigh more and will have fewer cases of physician-assessed severe pneumonia in the first year of life . Additionally , an extensive personal air pollution exposure monitoring effort opens the way for exposure-response analyses , which we will present alongside intention-to-treat analyses . Major funding was provided by the National Institute of Environmental Health Sciences , The Thrasher Research Fund , and the Global Alliance for Clean Cookstoves . Discussion Household air pollution exposure is a major health risk that requires well-tested interventions . GRAPHS will provide important new evidence on the efficacy of both efficient biomass cookstoves and LPG , and will thus help inform health and energy policies in developing countries . Trial registration The trial was registered with clinical trials.gov on 13 April 2011 with the identifier NCT01335490 Background Exposure to biomass fuel smoke is one of the leading risk factors for disease burden worldwide . International campaigns are currently promoting the widespread adoption of improved cookstoves in re source -limited setting s , yet little is known about the cultural and social barriers to successful improved cookstove adoption and how these barriers affect environmental exposures and health outcomes . Design We plan to conduct a one-year crossover , feasibility intervention trial in three re source -limited setting s ( Kenya , Nepal and Peru ) . We will enroll 40 to 46 female primary cooks aged 20 to 49 years in each site ( total 120 to 138 ) . Methods At baseline , we will collect information on sociodemographic characteristics and cooking practice s , and measure respiratory health and blood pressure for all participating women . An initial observational period of four months while households use their traditional , open-fire design cookstoves will take place prior to r and omization . All participants will then be r and omized to receive one of two types of improved , ventilated cookstoves with a chimney : a commercially-constructed cookstove ( Envirofit G3300/G3355 ) or a locally-constructed cookstove . After four months of observation , participants will crossover and receive the other improved cookstove design and be followed for another four months . During each of the three four-month study periods , we will collect monthly information on self-reported respiratory symptoms , cooking practice s , compliance with cookstove use ( intervention periods only ) , and measure peak expiratory flow , forced expiratory volume at 1 second , exhaled carbon monoxide and blood pressure . We will also measure pulmonary function testing in the women participants and 24-hour kitchen particulate matter and carbon monoxide levels at least once per period . Discussion Findings from this study will help us better underst and the behavioral , biological , and environmental changes that occur with a cookstove intervention . If this trial indicates that reducing indoor air pollution is feasible and effective in re source -limited setting s like Peru , Kenya and Nepal , trials and programs to modify the open burning of biomass fuels by installation of low-cost ventilated cookstoves could significantly reduce the burden of illness and death worldwide . Trial registration Clinical Trials.gov Background More than two-fifths of the world ’s population uses solid fuels , mostly biomass , for cooking . The result ing biomass smoke exposure is a major cause of chronic obstructive pulmonary disease ( COPD ) among women in developing countries . Objective To assess whether 
    Output:
    
Our results suggest that exposure to CO is not a consistently valid surrogate measure of exposure to PM2.5 .