Associated Studies


Adult Respiratory Health Study
This is an expansion of the Guatemala Stove Intervention Study focusing on lung health of the mothers of the infants enrolled. In common with most other poor communities in developing countries, it is women who receive the greatest pollution exposures due to their activities in the home and kitchen. Observational epidemiological studies in developing countries have shown that indoor air pollution from biomass and coal use is related to chronic respiratory symptoms, reduced lung function, and chronic obstructive pulmonary disease. The investigation of women’s respiratory health in the trial includes measurement of acute and chronic respiratory symptoms by questionnaire, repeated lung function using a Micromedical Microloop spirometer, and measurements of exposure. Baseline assessment will provide detailed description of the extent and severity of respiratory health in relation to pollution levels. Over the follow-up period of the study, we will investigate whether women’s symptoms and lung function can be improved by reducing indoor air pollution with the new stoves. In addition to support from the main study, the principal funding is a NOK 1 mill grant from the Norwegian Research Council, supplemented by funding from the World Health Organization (Departments of Child and Adolescent Health and Development, and Protection of the Human Environment).

Heart Rate Variability
Whereas hundreds of studies have examined the relationship between outdoor air pollution and heart disease, we are not aware of any study of the cardiovascular health effects of the higher particle air pollution levels in third-world households. By taking advantage of the randomized intervention in the main ALRI study, we are determining whether resting heart rate variability is lower among women over 40 years old who cook over traditional open fires compared to women who cook over the exposure-reducing plancha stove during a 12-month period. Lower heart rate variability is associated with mortality due to cardiovascular disease. Other health measures include pulmonary function, pulse oximetry, and blood pressure.

Continuous, particle and carbon monoxide personal exposure measures will allow exposure-response analyses for the short-term effect of peak pollution levels and the long-term effect of changes in average daily exposures. Although outdoor air pollution and environmental tobacco smoke have been associated with lower heart rate variability, this study will provide the first evidence about the cardiovascular health effects of biomass smoke. In addition, this will be the first air pollution study of any type to examine chronic changes in heart rate variability, which may help clarify long-term mortality effects. Funding: In addition to support from the NIH-funded childhood ARLI study, the cardiovascular study has received funding from the Kresge Center for Environmental Health at the Harvard School of Public Health.

Field Validation of High Capacity Inexpensive Continuous Particle Monitors
Measurement of particulate matter for population surveys in developing world settings using current technologies presents several difficulties. Normal gravimetric sampling requires the use of an environmentally controlled weigh room, and careful and skilled handling of pumps, balances, and filters. Thus, skilled technicians are needed for the surveys combined with multiple visits for filter changing, battery replacement, and calibration causing a burden on participants, potentially biasing household behaviors, and complicating logistics. Currently available real time data-logging particle monitors using light-scattering technology are prohibitively expensive, but are designed for particulate levels at least an order of magnitude lower than those experienced in residential settings in developing countries.

Under a grant from the Shell Foundation, we have developed inexpensive continuous particle monitors for use in surveys in the developing world to measure household pollution levels from cook stoves and other sources over time periods of at least seven days. After Laboratory validation tests we are now validating the use of these monitors in rural homes in Guatemala along with other commercially used devices and gravimetric sampling. These monitors will be incorporated a in standardized kits to monitor indoor air pollution in developing world settings that are currently being developed.

Stove Efficiency Study
The purpose of the stove efficiency test is to quantitatively compare the fuel use of the open fire and the plancha to help understand the non-health benefits of the stove intervention. In summer 2003, tests were piloted based on the revised VITA (Volunteers in Technical Assistance) stove testing methods, with small modifications. Two of the three VITA test were conducted to compare the plancha to the open fire. The Boiling Water Test (BWT) measures the amount of fuel consumed and the time required for a standaridized pot of water to come to a full boil and is able to derive an efficiency measure – percent energy in the fuel absorbed by the pot. The Kitchen Performance Test (KPT) more realistically simulates actual family usage by measuring fuel-wood consumption per day as they are used in the typical household environment. By measuring the amount of fuel-wood consumed in households with plancha or open fire, the KPT provides the most reliable indication of stove performance under actual household conditions, but does not provide a quantified estimate of physical efficiency for comparison to stoves in other regions. Incremental support is being provided by the Brian and Jennifer Maxell Endowed Chair in Public Health at UC Berkeley. Stove Efficiency Study Report (PDF)

Fuel Use Patterns
In Guatemala, as in much of the developing world, the rural population is primarily dependent on often increasingly stressed sources of wood and other biomass fuel . As part of our effort to understand the impact of the improved cookstove (plancha) used in the intervention trial, this study aims to characterize fuel sources, fuel use, and the factors affecting fuel consumption at the household level in the communities of the study area.. In particular, we want to know whether the households using the plancha perceive that they are saving fuel and, if so, how much of which types from which sources. This may tell us to what extent, if any, the plancha promotes natural resource conservation as well as health.

To address this question, we developed a household survey to begin to understand fuel characteristics, fuel sources (including changes in fuel sources over time), and fuel market structure as well as the fuel perceptions, preferences, and attitudes of the intervention trial participants. The results of the survey will be presented both quantitatively and qualitatively, including the creation of a GIS map to depict the pathway from fuel source to consumption. Incremental support is being provided by the Brian and Jennifer Maxell Endowed Chair in Public Health at UC Berkeley. Fuel Use Patterns Report (PDF)

Temascal IAQ Monitoring
The temescal, or chuj in Mam, is a type of sauna used in highland Guatemala. The chuj is a small mud-walled chamber located in the patio of most village houses, and is used once or twice a week for bathing by family members of all ages, including pregnant women and newborns. A wood fire is built in the chamber to heat rocks. After the fire is out, but while smoldering charcoal still remains, the family enters the chuj and sprinkles water on the rocks to produce steam resulting in a sauna-like interior environment. In the summer of 2003, a study will be conducted to measure carbon monoxide and particulate matter exposures in order to provide an idea of the contribution of indoor air pollution exposure among chuj users. Incremental support is being provided by the Brian and Jennifer Maxell Endowed Chair in Public Health at UC Berkeley. Temescal IAQ Monitoring Report (PDF)

Pending Funding

Asthma and Allergies
The infrastructure from the main study (ARI) will be utilized to study the following three components potentially related to asthma, allergies and respiratory infections in household children, including siblings: (1) a biomarker in urine for assessment of allergy related changes in immune status (eosinophilic protein X or EPX); (2) evaluation of the indoor household environment with assessment of dust-mite levels; and (3) stool samples for assessment of parasitic infestations. The biomarker will give us information on the influence of biomass smoke at the earliest stages of the maturation of the immune system, and help elucidate how sub-groups may develop immune-patterns and clinical features associated with later childhood asthma and allergy. Unfavorable indoor conditions and/or high dust mite levels, and parasitic infestations are both potential modifying agents in a development of asthma/allergic disease and EPX levels. The parasite component will give additional information about the prevalence and severity of such infestations among indigenous people in Guatemala, with possible public health implications. At this point, little relevant scientific literature on this topic exists. We are also planning an extension of the current intervention trial into a long-term cohort so that we can continue to monitor and study the development of asthma and allergies in the study children. Funding is being sought from the Norwegian Research Council and NIH.

Low Birth Weight
Exposure to ambient as well as indoor air pollution during pregnancy has been associated with adverse pregnancy outcomes, especially low birth weight. In numerous studies, both active and passive tobacco smoke have been shown to be risk factors for low birth weight. Thus far only one hospital-based study in Guatemala showed that indoor air pollution was associated with lower birth weight. The risk associated with indoor air pollution exposures from combustion of biomass fuels used for cooking and heating requires further study. The Stove Intervention Trial provides a unique opportunity to assess the impact of wood smoke exposure during pregnancy on adverse birth outcomes such as low birth weight (LBW; < 2500 grams), Intrauterine Growth Retardation (IUGR; < 10th percentile for gestational age and infant sex) and pre-term births (< 37 weeks gestation). A range of pre-natal measures on pregnant women and air pollution exposures are being conducted at present. If funded, plans for the future include an assessment of maternal pesticide exposures, a comprehensive nutritional assessment for dietary vitamin and mineral deficiencies, and a formal training for both fieldworkers and local midwives in gestational age and IUGR assessment techniques. Funding is currently being sought from the Global Forum for Health Research.

Hemoglobin and Indoor Air Quality
Indoor air pollution from the burning of such biomass fuels as wood and agricultural waste is associated with a higher risk of a number of respiratory problems. The effect on other health outcomes, such as fetal growth, has not yet been adequately documented.

The objective of this study was to determine whether, among women who burn biomass fuels for cooking indoors, the use of “smoky” fires is associated with elevated hemoglobin concentration in comparison to women using “smokeless” stoves, that is, stoves that are designed to reduce indoor air pollution. This research was conducted as part of a series of preliminary studies to determine the feasibility and potential health benefits of a randomized stove intervention to reduce indoor air pollution from the burning of biomass fuels for cooking.

Neufeld LM, Haas JD, Ruel MT, Grajeda R, Naeher LP. Smoky indoor cooking fires are associated with elevated hemoglobin concentration in iron-deficient women. Rev Panam Salud Publica. 2004; 15(2):110–18. View publication (PDF)