Clearing the Air: Lisa Thompson Helps Identify and Fight a Global Killer

May 2011Diana Austin

Oakland, California, is a long way from the highlands of Guatemala. Yet the connection between the respiratory ailments afflicting children in both regions helped lead the UCSF School of Nursing’s Lisa Thompson to a program of research on indoor air pollutants that, she and other researchers have found, cause more than a million premature deaths each year.

Recognizing the Problem

In the 1990s, while working as a family nurse practitioner for Oakland’s La Clínica de la Raza, Thompson noticed during home visits to families in some of Oakland’s poorer neighborhoods that the closer children with asthma lived to freeways, the more they tended to suffer from severe respiratory illnesses. Her observations have since been backed by data indicating that children with asthma living in West Oakland, where several of the area’s major freeways converge, are at significantly higher risk for hospitalization for asthma-related complaints than those in other parts of the county.

Her up-close observations of these health disparities led Thompson to get a master’s degree, followed by a PhD degree in environmental health sciences at UC Berkeley’s School of Public Health. “I’m a family practice nurse who thinks like an environmental scientist,” she says.

When she arrived at UC Berkeley, her clinical skills and research acumen, coupled with her fluency in Spanish, prompted researcher and Professor of Global Environmental Health Kirk R. Smith to invite her to join the Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) research team, whose field of study ultimately became the basis for her doctoral dissertation.

A training session with traditional birth attendants RESPIRE took Thompson to rural Guatemala. There, the research team conducted the first longitudinal study of the effects on children of exposure to indoor air pollutants (IAPs) generated by the biomass cooking stoves that are nearly ubiquitous in the region – present in up to 90 percent of households.

Guatemala is not alone in the use of these stoves, and the magnitude of the health problems they cause is hard to overstate. For people in much of the developing world, the stoves – which use biomass fuels such as wood, coal, animal dung and crop residue – are a primary source of heat and food preparation. Exposure to the resulting pollutants affects 3 billion people worldwide and causes an estimated 1.6 million excess deaths per year, according to the World Health Organization.

Better Stoves for Better Health

The western highlands of Guatemala have a particularly high infant mortality rate due to acute respiratory infection, and the RESPIRE team hypothesized that by reducing IAPs from the stoves, the rate might be reduced. The subsequent study was the first randomized stove intervention trial to evaluate the respiratory health effects of reducing indoor air pollution from open cooking fires.

A cohort of more than 500 Mam-speaking families was ultimately enrolled, with each of the enrolled households randomized to receive a new woodstove with a special chimney that improves ventilation – called a plancha – either at the beginning of the study period or when the child reached 18 months of age. The researchers trained Mam-speaking field-workers to take weekly health assessments of children ranging from newborn to 18 months of age, and periodically deployed small, inexpensive, passive carbon monoxide diffusion tubes to objectively measure carbon monoxide exposure.

The team found a significant reduction in both exposure to carbon monoxide and in chronic respiratory symptoms among the women and children in the intervention group. These results were disseminated among local communities and health centers, and are being used to make a case for plancha stove adoption via governmental and nongovernmental organizations.

More Than Respiratory Problems

While the association between wood smoke exposure and lower respiratory tract infection has now been well studied, other potential risks have not. During her time in Guatemala, Thompson became increasingly interested in how indoor air pollutants from woodstoves affect children’s growth and development.

This interest was spurred, in part, by her observation of a traditional practice among the highlanders of Guatemala: For three weeks postpartum, women and infants lie directly next to the woodstove or in an open-fire steam bath (temazcal) several times per day, which is thought to help them replace the heat lost during childbirth. Exposure to IAPs during pregnancy has been associated with low birthweight, and Thompson wondered whether the early and intensive exposure to IAPs from woodstoves and temazcales might have an even more lasting effect on these children.

She looked at the exposure to indoor air pollutants of the maternal-fetal cohort to measure the effect on fetal growth and birthweight, and found an average 83-gram (three-ounce) increase in birthweight among infants born to households that had received the plancha in the prenatal period.

“In terms of birthweight, 83 grams isn’t hugely significant,” says Thompson. “But it leads us to wonder what other effects exposure to indoor air pollutants have on child growth and development.” Her continuing research looks at the relationship between indoor air pollutant exposure and infant outcomes such as low birthweight, prematurity and delayed neurodevelopment.

Return on Investment

Making the connection between her research and her clinical work has always been an important goal for Thompson, and teaching other nurses offers an opportunity to make that happen. In addition to her role as an assistant professor in the Department of Family Health Care Nursing, she serves on the UCSF Global Health Sciences faculty and was a 2009 recipient of the Burke Family Global Health Faculty Award. The award provides a three-year salary and support for the faculty member’s research projects.

With that support, Thompson has returned to Guatemala several times, “wearing both my teaching and nursing hats,” since the conclusion of RESPIRE and the follow-up study, Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter (CRECER).

In 2008, she and School of Nursing Associate Clinical Professor Amy Levi took a group of UCSF nurse-midwifery students to Guatemala to help train traditional birth attendants to measure birthweights and estimate the gestational age of neonates. In 2009, midwifery students interviewed 40 traditional birth attendants about prenatal, intrapartum and postpartum care of Guatemalan women.

Her ongoing research in the region looks at cultural practices that increase exposure to indoor air pollution among women and newborns during the pregnancy and postpartum periods. “There’s no easy fix,” she says of the problem. “But reducing these exposures provides an enormous return on investment because it benefits the entire family.”