December 5, 2011

Wood Cooking Stoves Combat Pneumonia

Photo of an iron pot on a smoking fire

A new study found that wood-burning cooking stoves with chimneys lowered exposure to wood smoke from open cooking fires and reduced the rate of severe pneumonia by 30% in children less than 18 months of age.

Childhood deaths from pneumonia are relatively uncommon in the United States. But the disease kills more children worldwide than any other — almost 1.6 million children each year. Open fires used for heating and cooking are thought to be a major cause. A team of researchers led by Dr. Kirk Smith at the University of California, Berkeley, set out to test whether lowering wood smoke exposure could reduce pneumonia in children.

The study looked at 534 households in rural Guatemala with a pregnant woman or young infant. The households were randomly assigned to receive a locally developed stove with a chimney or to continue cooking using traditional open, indoor wood cooking fires. In all, 265 children were in chimney-stove homes and 253 children were in comparison homes with traditional cooking fires.

Trained field workers visited the homes every week for 2 years to record the children's health status. They referred sick children to physicians. They also checked to make sure the chimney stoves were working properly and arranged for any needed repairs. They took carbon monoxide measurements for 48 hours every 3 months to gauge levels of personal wood smoke exposure. The study, funded by NIH's National Institute of Environmental Health Sciences (NIEHS) and the World Health Organization, appeared in the November 12, 2011, issue of the Lancet.

The researchers saw a significantly reduction in severe childhood pneumonia in households with a chimney stove. The people in homes with chimney stoves had an average 50% lower exposure to carbon monoxide.

The intervention didn't significantly reduce the total number of childhood pneumonia cases. However, the drop in severe pneumonia would likely result in reduced childhood mortality, the researchers say.

“We found as large a benefit for severe pneumonia as more well-known public health interventions, such as vaccinations and nutrition supplements,” Smith says. “Future investments into viable, large-scale stove and fuel interventions to reduce child exposure to household air pollution are certainly worth making.”

“Exposure to smoke from cooking stoves is a major global public health problem that affects nearly half of the world's population and contributes to approximately 2 million deaths per year,” says NIEHS Director Dr. Linda Birnbaum. “This is one of the first studies that shows how an intervention can reduce indoor air pollution from wood smoke, so people can live healthier lives.”

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