Half of the world's population lacks access to cleaner energy
sources, such as electricity. More than three million premature deaths a
year and other serious health issues have been attributed to exposure to
smoke from cooking with solid fuels and kerosene, which are commonly
used throughout the developing world.
Hypertensive disease caused by
cooking-related household air pollution during pregnancy is a major
cause of death and disease for pregnant women and their infants.
‘Pregnant women who switched to ethanol from traditional cooking fuels such as firewood were more than three times less likely to develop high blood pressure than those who continued to use biofuels and kerosene.’
There are multiple benefits of
replacing stoves that burn solid fuels such as wood, crop wastes and
dung with clean-burning stoves.
In a small clinical trial that replaced widely used biomass and
kerosene cookstoves with clean-burning ethanol stoves, a team of
researchers from the University of Chicago and the University of Ibadan
(Nigeria) was able to reduce the risk of high blood pressure and
cardiovascular disease in pregnant women.
In their carefully controlled study, published online in the American Journal of Respiratory and Critical Care Medicine
the team found that pregnant women who switched to ethanol from
traditional cooking fuels such as firewood were more than three times
less likely to develop high blood pressure than those who continued to
use biofuels and kerosene. Those who switched from kerosene to ethanol
were more than four times less prone to elevated blood pressures.
"We hope our results will influence health policy discussion about
the dangers of exposure to household air pollution, a burden that falls
disproportionately on women and children," said pulmonologist
Christopher Sola Olopade, professor of medicine and clinical
director of the University of Chicago's Center for Global Health.The researchers enrolled 324 pregnant women from Ibadan, Nigeria, in
their study. None of the women had high blood pressure when they
entered the study. Women who smoked or lived with a smoker or who cooked
for a living were excluded.
Before the study, all of the women cooked with firewood or kerosene.
When the study reached weeks 16 to 18 of the pregnancy, half of the
women were assigned to cook only with ethanol and were given
ethanol-burning stoves and fuel. The other half continued to cook with
the traditional fuels, wood or kerosene, but they were encouraged to
cook outside or in a well-ventilated room to reduce their exposure.
The researchers found that 1.9% of the pregnant women who
cooked with ethanol developed high blood pressure at the last antenatal
visit, compared to 6.4% of those who cooked with wood and 8.8% of those who used kerosene.
"The initial objective of the study was to study birth outcomes
related to household air pollution," Olopade said. "We compared the
effects of the different cooking fuels on the mothers' blood pressure
and risk of preeclampsia, a serious complication of high blood pressure.
This is the first time that a randomized intervention study has shown
that there may be benefits to the mother as well."
"Our study adds to the evidence that interventions to reduce
exposure to household air pollution by introduction of cleaner fuels
should be widely implemented to mitigate health challenges faced by
vulnerable populations experiencing energy poverty, especially pregnant
women," Olopade said.
The team also followed the pregnancy outcomes, growth and
development of the fetus. "The long-term health consequences of in-utero
exposure of surviving babies to household air pollution, such as
decreased cognitive development, risk of developing asthma and lower
respiratory infection, need further investigation," Olopade said. "We
support the World Health Organization's push to remove kerosene as
cooking fuels from households."
This study was part of a long-term project. The researchers
previously demonstrated that cooking with fuels such as firewood is
associated with a significant increase in indoor levels of carbon
monoxide as well as elevated levels of very small lung-damaging
particulate matter, known as PM2.5, which can cause systemic
inflammation and lung damage.
They also demonstrated a preference among users for the efficiency
of the newer clean-burning stoves. Using ethanol as fuel reduced cooking
time, a popular benefit that also helped reduce airborne particulate
matter. In fact, 84% of women in the ethanol arm of the study
gave away their kerosene stoves; most of them did so within the first
month of the study.
"Switching to ethanol-based stoves," the authors conclude, "provides
much needed hope for a sustainable cooking alternative to unclean fuels
in low to middle income countries like Nigeria, where high-quality
ethanol is already being produced locally for cooking."