Congenial Heart Defects in Children Linked
to Environmental Toxins
From: Editor, ENN.com
Approximately 8 out of
every 1,000 newborns have congenial heart defects — abnormalities in the
heart's structure that happen due to incomplete or irregular development of the
fetus' heart during the first stages of the mother's pregnancy. While some are
known to be associated with genetic disorders, the cause of most of these heart
defects is unknown.
However, according to
research presented at the American Heart Association's Scientific Sessions
2013, heart defects in children may be associated with their mothers' exposure
to specific mixtures of environmental toxins during pregnancy.
"Although still in
the early stage, this research suggests some chemical emissions — particularly,
industrial air emissions — may be linked to heart abnormalities that develop
while the heart is forming in the womb," said lead researcher Deliwe P.
Ngwezi, M.D., a Ph.D., student and research fellow in pediatric cardiology at
the University of Alberta in Canada.
The study is based on
congenital heart defects diagnosed in 2004-11 and chemical emissions recorded
by a Canadian agency tracking pollutants.
Researchers looked at
three chemical categories, but only one group showed a strong correlation with
rates of congenital heart defects. According to Ngwezi, the group of chemicals
consists of a mixture of organic compounds and metals namely: benzene,
butadiene, carbon disulphide, chloroform, ethylene oxide, hexachlorobenzene,
tetrachloroethane, methanol, sulphur dioxide, toluene, lead, mercury and
cadmium.
Congenital heart defect
rates have gradually decreased in Canada since 2006, which is about the time
the government tightened regulations to reduce industrial air emissions, Ngwezi
said. The heart defect decreases were mainly associated with heart defects
resulting in holes between the upper and lower heart chambers (septal defects)
and malformations of the cardiac outflow tracts (conotruncal defects),
according to Ngwezi.
"For now, consumers
and healthcare providers should be educated about the potential toll of
pollutants on the developing heart," she said. "As we have observed
in the preliminary results, when the emissions decrease, the rates of
congenital heart defects also decrease."
This study, she said,
should draw attention to the increasing evidence about the impact of
environmental pollution on birth defects. Limitations of the study include that
researchers' observations were made at a group level, not according to
individual risk and the self-reported industry data which is monitored and
collected annually by government, according to Ngwezi.
Read more at the American Heart Association.
