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Background: Cooking-related biomass smoke is a major source of household air pollution (HAP) and an important health hazard. Prior studies identified associations between HAP exposure and childhood stunting; less is known for underweight and wasting. Few studies had personal HAP measurements., Methods: 557 households in rural Guatemala were enrolled in the CRECER study, the follow-up study of the RESPIRE randomized intervention trial. They were assigned to three groups that received chimney stoves at different ages of the study children. Multiple personal carbon monoxide (CO) exposure measurements were used as proxies for HAP exposures. Children's heights and weights were measured from 24 to 60 months of age. Height-for-age z-score (HAZ), weight-for-age z-score (WAZ), and weight-for-height z-score (WHZ) were calculated based on the World Health Organization's Multicentre Growth Reference Study. HAZ, WAZ, and WHZ below -2 were classified as stunting, underweight, and wasting, respectively. Generalized linear models and mixed effects models were applied., Results: 541 children had valid anthropometric data, among whom 488 (90.2 %) were stunted, 192 (35.5 %) were underweight, and 2 (0.3 %) were wasted. A 1 ppm higher average CO exposure was associated with a 0.21 lower HAZ (95 % CI: 0.17-0.25), a 0.13 lower WAZ (95 % CI: 0.10-0.17) and a 0.06 lower WHZ (95 % CI: 0.02-0.10).The associations for HAZ were stronger among boys (coefficient = -0.29, 95 % CI: -0.35 - -0.22) than among girls (coefficient = -0.15, 95 % CI: -0.20 - -0.10). A 1 ppm-year higher cumulative CO exposure was associated with a higher risk of moderate stunting among boys (OR = 1.27, 95 % CI: 1.05-1.59), but not among girls., Discussion: In this rural Guatemalan population, higher HAP exposure was associated with lower HAZ and WAZ. The associations between HAP and HAZ/stunting were stronger among boys. Reducing HAP might benefit childhood somatic growth in rural populations of low-income countries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Women and children in rural regions of low-income countries are exposed to high levels of household air pollution (HAP) as they traditionally tend to household chores such as cooking with biomass fuels. Early life exposure to air pollution is associated with aeroallergen sensitization and developing allergic diseases at older ages. This prospective cohort study assigned HAP-reducing chimney stoves to 557 households in rural Guatemala at different ages of the study children. The children's air pollution exposure was measured using personal CO diffusion tubes. Allergic outcomes at 4-5 years old were assessed using skin prick tests and International Study of Asthma and Allergies in Childhood (ISAAC)-based questionnaires. Children assigned to improved stoves before 6 months old had the lowest HAP exposure compared to the other groups. Longer exposure to the unimproved stoves was associated with higher risks of maternal-reported allergic asthma (OR = 2.42, 95% CI: 1.11-5.48) and rhinitis symptoms (OR = 2.01, 95% CI: 1.13-3.58). No significant association was found for sensitization to common allergens such as dust mites and cockroaches based on skin prick tests. Reducing HAP by improving biomass burning conditions might be beneficial in preventing allergic diseases among children in rural low-income populations.

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., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

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.

In Central America, the traditional temazcales or wood-fired steam baths, commonly used by many Native American populations, are often heated by wood fires with little ventilation, and this use results in high wood smoke exposure. Urinary mutagenicity has been previously employed as a non-invasive biomarker of human exposure to combustion emissions. This study examined the urinary mutagenicity in 19 indigenous Mayan families from the highlands of Guatemala who regularly use temazcales (N = 32), as well as control (unexposed) individuals from the same population (N = 9). Urine samples collected before and after temazcal exposure were enzymatically deconjugated and extracted using solid-phase extraction. The creatinine-adjusted mutagenic potency of urine extracts was assessed using the plate-incorporation version of the Salmonella mutagenicity assay with strain YG1041 in the presence of exogenous metabolic activation. The post-exposure mutagenic potency of urine extracts were, on average, 1.7-fold higher than pre-exposure samples (P < 0.005) and also significantly more mutagenic than the control samples (P < 0.05). Exhaled carbon monoxide (CO) was ~10 times higher following temazcal use (P < 0.0001), and both CO level and time spent in temazcal were positively associated with urinary mutagenic potency (i.e. P < 0.0001 and P = 0.01, respectively). Thus, the wood smoke exposure associated with temazcal use contributes to increased excretion of conjugated mutagenic metabolites. Moreover, urinary mutagenic potency is correlated with other metrics of exposure (i.e. exhaled CO, duration of exposure). Since urinary mutagenicity is a biomarker associated with genetic damage, temazcal use may therefore be expected to contribute to an increased risk of DNA damage and mutation, effects associated with the initiation of cancer., (© The Author 2014. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society.)

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.

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/m(3)) and CO (median [IQR] = 1.18 [0.50, 2.37] mg/m(3)) 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.

We investigated whether early life chronic exposure to woodsmoke, using personal passive 48-h carbon monoxide (CO) as an indicator, is associated with children's neurodevelopmental and behavioral performance. CO measures were collected every 3 months from 2002 to 2005 among mother-child dyads during the Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) stove intervention trial in San Marcos, Guatemala. From March to June, 2010, study children of age 6-7 years, performed a follow-up non-verbal, culturally adapted neurodevelopmental assessment. We found inverse associations between CO exposure of pregnant mothers during their 3rd trimesters (m=3.8ppm ± 3.0ppm; range: 0.6-12.5 ppm) and child neuropsychological performance. Scores on 4 out of 11 neuropsychological tests were significantly associated with mothers' 3rd trimester CO exposures, including visuo-spatial integration (p<0.05), short-term memory recall (p<0.05), long-term memory recall (p<0.05), and fine motor performance (p<0.01) measured using the Bender Gestalt-II's Copy, Immediate Recall, and an adapted version of a Delayed Recall Figures drawing, and the Reitan-Indiana's Finger Tapping Tests, respectively. These 4 significant finding persisted with adjustment for child sex, age, visual acuity, and household assets (socio-economic status). Summary performance scores were also significantly associated with maternal 3rd trimester CO when adjusted for these covariates. Other variables accounting for variance but were excluded in our final multiple regression models included the following: HOME environment stimulation score, child examiner, WHO height-for-age percentile, and age that the infant stopped breastfeeding. This seems to be the first study on woodsmoke exposure and neurodevelopment, and the first longitudinal birth cohort study on chronic early life CO exposures, determined by high quality measures of mothers' and infants' personal CO exposures, and using well-established, reliable child neuropsychological tests. Further research is needed to replicate our results and inform future interventions and air quality standards for woodsmoke and CO., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Pneumonia causes more child deaths than does any other disease. Observational studies have indicated that smoke from household solid fuel is a significant risk factor that affects about half the world's children. We investigated whether an intervention to lower indoor wood smoke emissions would reduce pneumonia in children., Methods: We undertook a parallel randomised controlled trial in highland Guatemala, in a population using open indoor wood fires for cooking. We randomly assigned 534 households with a pregnant woman or young infant to receive a woodstove with chimney (n=269) or to remain as controls using open woodfires (n=265), by concealed permuted blocks of ten homes. Fieldworkers visited homes every week until children were aged 18 months to record the child's health status. Sick children with cough and fast breathing, or signs of severe illness were referred to study physicians, masked to intervention status, for clinical examination. The primary outcome was physician-diagnosed pneumonia, without use of a chest radiograph. Analysis was by intention to treat (ITT). Infant 48-h carbon monoxide measurements were used for exposure-response analysis after adjustment for covariates. This trial is registered, number ISRCTN29007941., Findings: During 29,125 child-weeks of surveillance of 265 intervention and 253 control children, there were 124 physician-diagnosed pneumonia cases in intervention households and 139 in control households (rate ratio [RR] 0·84, 95% CI 0·63-1·13; p=0·257). After multiple imputation, there were 149 cases in intervention households and 180 in controls (0·78, 0·59-1·06, p=0·095; reduction 22%, 95% CI -6% to 41%). ITT analysis was undertaken for secondary outcomes: all and severe fieldworker-assessed pneumonia; severe (hypoxaemic) physician-diagnosed pneumonia; and radiologically confirmed, RSV-negative, and RSV-positive pneumonia, both total and severe. We recorded significant reductions in the intervention group for three severe outcomes-fieldworker-assessed, physician-diagnosed, and RSV-negative pneumonia--but not for others. We identified no adverse effects from the intervention. The chimney stove reduced exposure by 50% on average (from 2·2 to 1·1 ppm carbon monoxide), but exposure distributions for the two groups overlapped substantially. In exposure-response analysis, a 50% exposure reduction was significantly associated with physician-diagnosed pneumonia (RR 0·82, 0·70-0·98), the greater precision resulting from less exposure misclassification compared with use of stove type alone in ITT analysis., Interpretation: In a population heavily exposed to wood smoke from cooking, a reduction in exposure achieved with chimney stoves did not significantly reduce physician-diagnosed pneumonia for children younger than 18 months. The significant reduction of a third in severe pneumonia, however, if confirmed, could have important implications for reduction of child mortality. The significant exposure-response associations contribute to causal inference and suggest that stove or fuel interventions producing lower average exposures than these chimney stoves might be needed to substantially reduce pneumonia in populations heavily exposed to biomass fuel air pollution., Funding: US National Institute of Environmental Health Sciences and WHO., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: A large body of evidence suggests that fine particulate matter (PM) air pollution is a cause of cardiovascular disease, but little is known in particular about the cardiovascular effects of indoor air pollution from household use of solid fuels in developing countries. RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects) was a randomized trial of a chimney woodstove that reduces wood smoke exposure., Objectives: We tested the hypotheses that the stove intervention, compared with open fire use, would reduce ST-segment depression and increase heart rate variability (HRV)., Methods: We used two complementary study designs: a) between-groups comparisons based on randomized stove assignment, and b) before-and-after comparisons within control subjects who used open fires during the trial and received chimney stoves after the trial. Electrocardiogram sessions that lasted 20 hr were repeated up to three times among 49 intervention and 70 control women 38-84 years of age, and 55 control subjects were also assessed after receiving stoves. HRV and ST-segment values were assessed for each 30-min period. ST-segment depression was defined as an average value below -1.00 mm. Personal fine PM [aerodynamic diameter ≤ 2.5 μm (PM₂.₅] exposures were measured for 24 hr before each electrocardiogram., Results: PM₂.₅ exposure means were 266 and 102 μg/m³ during the trial period in the control and intervention groups, respectively. During the trial, the stove intervention was associated with an odds ratio of 0.26 (95% confidence interval, 0.08-0.90) for ST-segment depression. We found similar associations with the before-and-after comparison. The intervention was not significantly associated with HRV., Conclusions: The stove intervention was associated with reduced occurrence of nonspecific ST-segment depression, suggesting that household wood smoke exposures affect ventricular repolarization and potentially cardiovascular health.

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.

The use of wood-fired steam baths, or temazcales, is a potentially dangerous source of CO exposure in Guatemalan Highland communities where adults and children use them regularly for bathing, relaxation, and healing purposes. Physical characteristics of children predispose them to absorb CO faster than adults, placing them at greater exposure and health risks. Efforts to quantify temazcal exposures across all age groups, however, have been hampered by the limitations in exposure measurement methods. In this pilot study we measured COHb levels in children and adults following use of the temazcal using three field-based, non-invasive CO measurement methods: CO-oximetry, exhaled breath, and by estimation of COHb using micro-environmental concentrations and time diaries. We then performed a brief comparison of methods. Average CO concentrations measured during temazcal use were 661 ± 503 ppm, approximately 10 times the 15 min WHO guideline. Average COHb levels for all participants ranged from 12-14% (max of 30%, min 2%), depending on the method. COHb levels measured in children were not significantly different from adults despite the fact that they spent 66% less time exposed. COHb measured by CO-oximetry and exhaled breath had good agreement, but precision of the former was affected substantially by random instrument error. The version of the field CO-oximeter device used in this pilot could be useful in screening for acute CO exposure events in children but may lack the precision for monitoring the burden from less extreme, but more day-to-day CO exposures (e.g. indoor solid fuel use). In urban settings, health effects in children and adults have been associated with chronic exposure to ambient CO concentrations much lower than measured in this study. Future research should focus on reducing exposure from temazcales through culturally appropriate modifications to their design and practices, and targeted efforts to educate communities on the health risks they pose and actions they can take to reduce this risk.

The temazcal is a wood-fired steam bath used in the rural highlands of Guatemala for bathing and healing. We measured carbon monoxide (CO) among 288 participants in 72 temazcales. Participants were drawn from communities who participated in the RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects) chimney stove intervention trial. Temazcal CO exposures were extremely high, averaging 431 parts per million (time-weighted average). Compared to kitchen wood-smoke exposures, the temazcal contributes significantly to weekly exposures, despite the fact that the population spends less time in the temazcal than in the kitchen. This report 1) describes temazcal use patterns; 2) reports participants' signs and symptoms during temazcal use; 3) models the distribution of temazcal CO concentrations; 4) assesses reliability of exhaled breath CO as a biomarker of CO exposure; and 5) provides a proportional analysis of CO concentrations from temazcal use, as compared to kitchen concentrations.

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.

As a part of a longitudinal study in the highlands of Guatemala to elicit the chronic health effects of wood smoke from cooking, mean area and personal 48 h concentrations of 2.5 microm particulate matter (PM2.5) and carbon monoxide (CO) were measured every 3 months over 19 months. Monitoring was conducted in 63 households, 28 using traditional open wood fires and 35 using wood cookstoves with chimneys. The goal of this paper is to estimate personal exposure concentrations to PM2.5 using the measurements from CO diffusion tubes as a proxy. CO tubes are cheaper and easier to use than PM-monitoring devices, and can be worn by all family members, even infants. The relationship of PM2.5 and CO was determined by comparing measurements from both co-located instruments. CO measurements in ppm were corrected for temperature and pressure to mass concentrations. PM2.5 exposure was modeled with the following linear regression created using measured concentrations: PM2.5 (mg m(-3)) = 0.10 (0.093, 0.12) x CO (mg m(-3)) + 0.067 (0.0069, 0.13), R(2) = 0.76. No significant difference was found between the separate regressions for open fires and cookstoves. No significant improvement was obtained by applying a mixed statistical model. The equation was used to estimate personal exposures of PM2.5 using personal CO measurements from CO tubes worn by women, infants under 18 months, and children 48-72 months. Estimated 48 h mean personal PM2.5 concentrations for mother, infants, and children in open-fire homes were 0.27 +/- 0.02, 0.20 +/- 0.02, and 0.16 +/- 0.02 mg m(-3) respectively. In chimney-stove homes, mothers and children experienced PM2.5 personal concentrations of 0.22 +/- 0.03 and 0.14 +/- 0.03 mg m(-3), respectively.

The RESPIRE and CRECER studies measured the effects of reduced household air pollution (HAP) from wood-fired cookstoves on respiratory health in rural highland Guatemala. This article examines behavior change and leadership skill development in local community members who were hired as fieldworkers to assist with research. Fieldworkers administered household questionnaires, shared functions similar to community health workers, and bridged health resources to communities. A mixed-methods design for data collection (in-depth interviews, focus groups, impact drawings, knowledge questionnaire, and retrospective pre-test) was used. Purposive sampling included 10 fieldworkers and 13 local service providers. Fieldworkers showed an increase in knowledge, positive attitudes, and practices around HAP. They developed new technical, interpersonal, and leadership skills. Fieldworkers played a crucial role in building confianza (trust) with the community, bridging resources, and improving outside researchers' relationships with locals. Recommendations for future researchers include inclusion of additional training courses and adoption of community participatory approaches.

Exposure to household wood smoke from cooking is a risk factor for chronic obstructive lung disease among women in developing countries. The Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) is a randomized intervention trial evaluating the respiratory health effects of reducing indoor air pollution from open cooking fires. A total of 504 rural Mayan women in highland Guatemala aged 15-50 years, all using traditional indoor open fires, were randomized to either receive a chimney woodstove (plancha) or continue using the open fire. Assessments of chronic respiratory symptoms and lung function and individual measurements of carbon monoxide exposure were performed at baseline and every 6 months up to 18 months. Use of a plancha significantly reduced carbon monoxide exposure by 61.6%. For all respiratory symptoms, reductions in risk were observed in the plancha group during follow-up; the reduction was statistically significant for wheeze (relative risk = 0.42, 95% confidence interval: 0.25, 0.70). The number of respiratory symptoms reported by the women at each follow-up point was also significantly reduced by the plancha (odds ratio = 0.7, 95% confidence interval: 0.50, 0.97). However, no significant effects on lung function were found after 12-18 months. Reducing indoor air pollution from household biomass burning may relieve symptoms consistent with chronic respiratory tract irritation.

Background: Epidemiology frequently relies on surrogates of long-term exposures, often either individual-level short-term measurements or group-level based on long-term characteristics of subjects and their environment. Whereas individual-level measures are often imprecise due to within-subject variability, group-level measures tend to be inaccurate due to residual between-subject variability within groups. Rather than choose between these error-prone estimates, we borrow strength from each by use of mixed-model prediction and we compare the predictive validity., Methods: We compared alternative measures of long-term exposure to carbon monoxide (CO) among children in the RESPIRE woodstove randomized control trial during years 2003 and 2004. The main study included 1932 repeated 48-hour-average personal CO measures among 509 children from 0-18 months of age. We used a validation study with additional CO measures among a random subsample of 70 of the children to compare the predictive validity of individual-level estimates (based on observed short-term exposures), group-level estimates (based on stove type and other residential characteristics), and mixed-model predictions that combine these 2 sources of information., Results: The estimated error variance for mixed-model prediction was 63% lower than the individual-level measure based on the exposure data and 58% lower than the corresponding group-level measure., Conclusions: When both individual- and group-level estimates are available but imperfect, mixed-model prediction may provide substantially better measures of long-term exposure, potentially increasing the sensitivity of epidemiologic studies to underlying causal relations.

Setting: Indoor air pollution from burning of biomass fuel in open fires is a known risk factor for chronic obstructive pulmonary disease (COPD) in developing countries., Objective: To estimate the prevalence of respiratory symptoms and lung function among women in rural Guatemala and to describe the methods and practical issues associated with the assessment of respiratory health., Design: Information about respiratory symptoms, lung function and individual measurement of exposure was collected cross-sectionally among 350 Mayan-Indian women aged 15-50 years who used traditional open fires., Results: These women, exposed to indoor air pollution since birth, had a relatively high prevalence of cough (22.6%), phlegm (15.1%), wheeze (25.1%) and tightness in the chest (31.4%). Respiratory symptoms were positively associated with exposure levels. Lung function was higher than the most feasible reference population (average above predicted forced expiratory volume in 1 s [FEV(1)] +4.5% and forced vital capacity [FVC] +4.2%). Only one woman had a FEV(1)/FVC ratio lower than 70%., Conclusions: According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, almost one third of these young non-smoking women were at risk (stage 0) of developing COPD. The methodological issues encountered during the study highlight the importance of standardising approaches to local adaptation of established questionnaires to study respiratory health in rural areas of developing countries.

We have developed a small, light, passive, inexpensive, datalogging particle monitor called the "UCB" (University of California Berkeley particle monitor). Following previously published laboratory assessments, we present here results of tests of its performance in field settings at high particle concentrations. We demonstrate the mass sensitivity of the UCB in relation to gravimetric filter-based PM(2.5) mass estimates as well as commercial light-scattering instruments co-located in field chamber tests and in kitchens of wood-burning households. The coefficient of variation of the unadjusted UCB mass response in relation to gravimetric estimates was 15%. Although requiring adjustment for differences in sensitivity, inter-monitor performance was consistently high (r(2) > 0.99). Moreover, the UCB can consistently estimate PM(2.5) mass concentrations in wood-burning kitchens (Pearson r(2) = 0.89; N = 99), with good agreement between duplicate measures (Pearson r(2) = 0.94; N = 88). In addition, with appropriate cleaning of the sensing chamber, UCB mass sensitivity does not decrease with time when used intensively in open woodfire kitchens, demonstrating the significant potential of this monitor.

Objective: Trials of environmental risk factors and acute lower respiratory infections (ALRI) face a double challenge: implementing sufficiently sensitive and specific outcome assessments, and blinding. We evaluate methods used in the first randomized exposure study of pollution indoors and respiratory effects (RESPIRE): a controlled trial testing the impact of reduced indoor air pollution on ALRI, conducted among children 90% of children meeting ALRI criteria, of whom about 70% attended a physician. Referrals for cough without respiratory signs and self-referrals contributed 19.0% and 17.9% of physician-diagnosed ALRI cases respectively. Intervention group attendance following ALRI referral was 7% higher than controls, a trend also seen in compliance with RSV tests and CXR. There was no evidence of bias by intervention status in fieldworker classification or physician diagnosis. Incidence of fieldworker ALRI (1.12 episodes/child/year) is consistent with high sensitivity and low specificity; incidence of physician-diagnosed ALRI (0.44 episodes/child/year) is consistent with comparable studies., Conclusion: The combination of case-finding methods achieved good sensitivity and specificity, but intervention cases had greater likelihood of reaching the physician and being investigated. There was no evidence of bias in fieldworkers classifications despite lack of concealment at home visits. Pulse oximetry offers practical, objective severity assessment for field studies of ALRI.

Background and Objective: RESPIRE, a randomized trial of an improved cookstove, was conducted in Guatemala to assess health effects of long-term reductions in wood smoke exposure. Given the evidence that ambient particles increase blood pressure, we hypothesized that the intervention would lower blood pressure., Methods: TWO STUDY DESIGNS WERE USED: a) between-group comparisons based on randomized stove assignment, and b) before-and-after comparisons within subjects before and after they received improved stoves. From 2003 to 2005, we measured personal fine particle (particulate matter with aerodynamic diameter < 2.5 microm; PM(2.5)) exposures and systolic (SBP) and diastolic blood pressure (DBP) among women > 38 years of age from the chimney woodstove intervention group (49 subjects) and traditional open wood fire control group (71 subjects). Measures were repeated up to three occasions., Results: Daily average PM(2.5) exposures were 264 and 102 microg/m(3) in the control and intervention groups, respectively. After adjusting for age, body mass index, an asset index, smoking, secondhand tobacco smoke, apparent temperature, season, day of week, time of day, and a random subject intercept, the improved stove intervention was associated with 3.7 mm Hg lower SBP [95% confidence interval (CI), -8.1 to 0.6] and 3.0 mm Hg lower DBP (95% CI, -5.7 to -0.4) compared with controls. In the second study design, among 55 control subjects measured both before and after receiving chimney stoves, similar associations were observed., Conclusion: The between-group comparisons provide evidence, particularly for DBP, that the chimney stove reduces blood pressure, and the before-and-after comparisons are consistent with this evidence.

Background: Indoor air pollution (IAP) from combustion of biomass fuels represents a global health problem, estimated to cause 1.6 million premature deaths annually., Aims: RESPIRE (Randomised Exposure Study of Pollution Indoors and Respiratory Effects) Guatemala is the first randomised controlled trial ever performed on health effects from solid fuel use. Its goal is to assess the effect of improved stoves (planchas) on exposure and health outcomes in a rural population reliant on wood fuel., Methods: Questions about symptoms were asked at baseline and periodically after the intervention, to an initial group of 504 women (259 randomly assigned to planchas (mean (standard deviation) age 27.4 (7.2) years) and 245 using traditional open fires (28.1 (7.1) years)). Levels of carbon monoxide (CO) in exhaled breath, a biomarker of recent exposure to air pollution from biomass combustion, were measured at each visit. In addition to reducing IAP levels, the plancha may also have a positive health effect by changing the working posture to an upright position., Results: A high prevalence of eye discomfort, headache and backache was found. The odds of having sore eyes and headache were substantially reduced in the plancha group relative to the group using open fires for the follow-up period (odds ratio (OR) 0.18, 95% confidence interval (CI) 0.11 to 0.29 and (OR) 0.63, 95% CI 0.42 to 0.94, respectively). Median CO in breath among women in the intervention trial was significantly lower than controls., Conclusion: In addition to reducing discomfort for women, tangible improvements in symptoms experienced by a substantial proportion of women may help to gain acceptance and wider use of planchas.

We estimated the prevalence and severity of asthma, and the association with cooking on open wood fires, as preparation for a large-scale randomized field trial on effects of indoor air pollution and child health. This is one of the first systematic studies of asthma and indoor wood-smoke pollution and to our knowledge the first asthma study in a purely indigeneous population in Latin America. The mothers of 1058 children aged 4-6 years were interviewed, using the standardized ISAAC (International Study of Asthma and Allergies in Childhood) procedures and questionnaire. The study population is a Mam-speaking (Maya), indigenous group living at relatively high altitude (2000 m) in Western Guatemalan Highlands. We found that asthma prevalence is low among indigenous children in Guatemala, compared to other populations in Latin America. Only 3.3% of the children reported wheezing symptoms in the last 12 months, and 72% wheezing symptoms ever. The majority of the current wheezers had at least one of the criteria for severe asthma. The prevalence of all the symptoms of asthma was higher in children from households that used open fires compared to improved stoves with chimneys. In a logistic regression model, use of open fire for cooking was a significant risk factor for a number of asthma symptoms, with odds ratios varying from 2.0 to 3.5. Among the different cooking technologies (1-improved stove with chimney, 2-mixture of gas and open fire, 3-open fire) trends of higher prevalence with more pollution was found for some of the symptoms. Hence use of open fire for cooking, may be an important risk factor for asthma symptoms and severity.

The goal of this study was to assess the impact of improved stoves, house ventilation, and child location on levels of indoor air pollution and child exposure in a rural Guatemalan population reliant on wood fuel. The study was a random sample of 204 households with children less than 18 months in a rural village in the western highlands of Guatemala. Socio-economic and household information was obtained by interview and observation. Twenty-four hour carbon monoxide (CO) was used as the primary measure of kitchen pollution and child exposure in all homes, using Gastec diffusion tubes. Twenty-four hour kitchen PM(3.5) was measured in a random sub-sample (n=29) of kitchens with co-located CO tubes. Almost 50% of the homes still used open fires, around 30% used chimney stoves (planchas) mostly from a large donor-funded programme, and the remainder of homes used various combinations including bottled gas and open fires. The 24-h kitchen CO was lowest for homes with self-purchased planchas: mean (95% CI) CO of 3.09 ppm (1.87-4.30) vs. 12.4 ppm (10.2-14.5) for open fires. The same ranking was found for child CO exposure, but with proportionately smaller differentials (P<0.0001). The 24-h kitchen PM(3.5) in the sub-sample showed similar differences (n=24, P<0.05). The predicted child PM for all 203 children (based on a regression model from the sub-sample) was 375 microg/m(3) (270-480) for self-purchased planchas and 536 microg/m(3) (488-584) for open fires. Multivariate analysis showed that stove/fuel type was the most important determinant of kitchen CO, with some effect of kitchen volume and eaves. Stove/fuel type was also the key determinant of child CO, with some effect of child position during cooking. The improved stoves in this community have been effective in reducing indoor air pollution and child exposure, although both measures were still high by international standards. Large donor-funded stove programmes need to aim for wider acceptance and uptake by the local families. Better stove maintenance is also required.

Improved biomass cookstoves have the potential to reduce pollutant emissions and thereby reduce pollution exposure among populations in developing countries who cook daily with biomass fuels. However, evaluation of such interventions has been very limited. This article presents results from a study carried out in 30 households in rural Guatemala. Twenty-four hour PM3.5 concentrations were compared over 8 months for three fuel/cookstove conditions (n = 10 households for each condition): a traditional open fire cookstove, an improved cookstove called the plancha mejorada, and a liquefied petroleum gas (LPG) stove/open fire combination. Twenty-four hour geometric mean PM3.5 concentrations were 1560 micrograms/m3 (n = 58; 95% C.I. 1310, 1850), 280 micrograms/m3 (n = 59; 95% C.I. 240-320), and 850 micrograms/m3 (n = 60; 95% C.I. 680-1050) for the open fire, plancha, and LPG/open fire combination, respectively. A generalized estimating equation model showed a 45% reduction in PM3.5 concentrations for the LPG/open fire combination as compared to the open fire alone. The difference approached significance (p < 0.0737). The plancha showed an 85% reduction in PM3.5 concentrations as compared to the open fire (p < 0.0001). An analysis of the interaction of time with stove type showed that the temporal trend in pollution did not significantly differ among the three stove types. The reduced PM3.5 concentrations were maintained over time. Season did not affect pollutant concentrations. Of the two interventions, the plancha appears to offer the best prospects for achieving substantial reductions in indoor air pollution levels, although issues of cost and stove maintenance remain to be addressed.

Kitchen-area 22-h gravimetric PM2.5 and passive diffusion stain-tube carbon monoxide (CO) concentrations were measured in homes with open fire and improved wood cookstoves in two studies. In the first study (Guat-2), which also studied homes with gas cookstoves, three samples were collected per stove condition from each of three test houses. In the second study (Guat-3), one sample was collected per house from 15 open fire and 25 improved-stove houses. CO personal samples were also taken for mother and child in both studies. Spearman correlation coefficients (R) between kitchen-area CO and PM2.5 levels in homes using open fires or impoved wood cookstoves were high ranging from 0.92 (Guat-2) to 0.94 (Guat-3), as were those between the personal samples for mother and child ranging from 0.85 (Guat-3) to 0.96 (Guat-2). In general, the correlations were lower for less-polluted conditions. The study found that CO is a good proxy for PM2.5 in homes using open fires or planchas (improved wood cookstove with chimney) but not under gas stove use conditions. It also determined that mother personal CO is a good proxy for child's (under 2 years of age) personal CO and that area CO measurements are not strongly representative of personal CO measurements. These results generally support the use of Draeger CO passive diffusion tubes as a proxy for PM2.5 in such cases where a single type of emission source is the predominant source for CO and PM2.5.

Continuous particles less than 2.5 microm in diameter (PM2.5) and carbon monoxide (CO) were monitored during breakfast, lunch, and dinner in three high-density and four low-density villages near Quetzaltenango, Guatemala to help assess the viability of this region for a proposed respiratory health and stove intervention study. Approximately 15 homes were visited during each mealtime in each of the seven villages; in all, 98 homes were visited, with a sampling duration of 2-3 min per home per meal. For each village, a line (transect) was drawn on a village map along existing roads from one end of the village to the other; homes and between-home outside locations along the transect were monitored. Although the predominant stove type was the open fire, several other stoves, in various levels of disrepair, were observed frequently. The highest indoor concentrations of PM2.5 were observed in homes using the open fire (avg. = 5.31 mg/m3; SD=4.75 mg/m3) or equivalent, although homes using the plancha--indigenous wood-burning stove with chimney--also had measurements > 13.8 mg/m3, PM2.5 limit of detection. The highest indoor concentrations of CO were also observed in homes using the open fire (avg. = 22.9 ppm; SD = 28.1 ppm), with a maximum measurement of > 250 ppm. For both PM2.5 and CO, levels measured in homes with plancha, lorena, or open fire were significantly higher than levels taken in the street or in homes using a gas stove. The Spearman correlation coefficient between PM2.5 and CO for all data combined was 0.81, and ranged from 0.30 for the lorena to 0.68 for the plancha in homes using wood-fueled stoves. Although indoor PM2.5 and CO levels were not significantly different between high- and low-density villages, street-level PM2.5 (p = 0.002) and CO (p= 0.002), were significantly higher in the high - density villages. These data provide a useful picture of the pollution levels coming from a range of cooking stoves in various levels ofdisrepair, as well as a representation of how outdoor particle mass and CO levels vary from high- versus low-density villages.

Area 22-h average carbon monoxide (CO), total suspended particulates (TSP), particles less than 10 microns in diameter (PM10), and particles less than 2.5 microns in diameter (PM2.5) measurements were made in three test homes of highland rural Guatemala in kitchens, bedrooms, and outdoors on a longitudinal basis, i.e. before and after introduction of potential exposure-reducing interventions. Four cookstove conditions were studied sequentially: background (no stove in use); traditional open woodstove, improved woodstove with flue (plancha), and bottled-gas (LPG) stove. With nine observations each, kitchen PM2.5 levels were 56 micrograms/m3 under background conditions, 528 micrograms/m3 for open fire conditions, 96 micrograms/m3 for plancha conditions, and 57 micrograms/m3 for gas stove conditions. Corresponding PM10/TSP levels were 173/174, 717/836, 210/276, 186/218 micrograms/m3. Corresponding CO levels were 0.2, 5.9, 1.4, 1.2 ppm. Comparisons with other studies in the area indicate that the reductions in indoor concentrations achieved by improved wood-burning stoves deteriorate with stove age. Mother and child personal CO and PM2.5 measurements for each stove condition demonstrate the same trend as area measurements, but with less differentiation.