NEW YORK (Reuters Health) - Households in developing countries that regularly burn wood, straw, dung and other natural materials are more likely to also contain children with anemia, a new report finds.
Families in 29 countries who burned so-called “biofuels” for cooking or heating were 7 percent more likely to include a child with mild anemia.
When the researchers from McMaster University in Canada compared national-level data, they found that the countries with more residents burning biofuels were also home to more children with moderate or severe anemia.
“As a substantial proportion of people still rely on biofuels for domestic energy in developing countries, they need to be aware that exposure to biofuel smoke is associated with health risks and that they need to protect their children and themselves from being exposed to this harmful smoke,” study author Hmwe Hmwe Kyu told Reuters Health.
Nearly half of children under the age of 5 living in developing countries develop anemia, putting them at risk of cognitive impairments, developmental problems, and other serious, potentially life-threatening consequences.
Anemia is caused by a deficiency of blood cells or of hemoglobin, the iron-rich molecules within blood cells that transport oxygen from the lungs to body tissues.
Inhaling smoke from burning biofuels has already been linked to a host of other health problems, such as low birth weight and pneumonia in children.
In theory, burning biofuels could also cause anemia because the smoke contains pollutants such as carbon monoxide, which binds to and reduces the available amount of hemoglobin, and other compounds that can destroy red blood cells directly.
Burning natural materials for cooking and heating remains very common in developing countries, however, and the number of people who rely on biofuels is expected to climb to 2.6 billion by 2030.
To investigate whether burning biofuels might indeed increase the risk of anemia, Kyu and colleagues reviewed data collected from families living in 29 developing countries in Africa, Asia and the Caribbean region. In all, 117,454 children were represented in the study.
Given that other aspects of life in those countries might be behind an apparent biofuel-anemia link, the researchers used statistical tools to control for the influence of poverty, childhood illness, smoking, and other potentially confounding factors.
Reporting in the Annals of Epidemiology, they found that 24 percent of children had mild forms of anemia, and nearly 39 percent had a more moderate to severe form of the condition.
In addition, they found that the relationship between anemia and exposure to biofuels was exacerbated when children also had diarrhea or a fever. In other words, compared with children who were not exposed to biofuel smoke and did not have diarrhea, exposed children with diarrhea were 22 percent more likely to have mild anemia.
If breathing in smoke from natural materials is triggering childhood anemia, improved stoves might help, the authors note - however, each unit likely costs anywhere from $25 to $150, Kyu said in an e-mail to Reuters Health.
They acknowledge that the smoke may not be the only source of the problem and they were unable to tease out the possible roles of all other factors. “For example, we were not able to control for intestinal parasitic infections and lead poisoning, which may have contributed to residual confounding in our study,” Kyu added.
Kyu cautioned that the study focused on use of biofuels by individuals, and does not discuss the potential effects of living near a facility manufacturing ethanol for widespread use, for instance. “The results may not apply to large-scale biofuel efforts.”
SOURCE: link.reuters.com/qaj92q Annals of Epidemiology, November 2010.