環境有害物質は先天性心奇形と関連する（AHA:RESS Abstract 1）

小児における先天性心奇形率と一部の産業汚染物質の間に相関が認められた　
Correlation found between rates of congenital heart defects in children and emissions of some industrial pollutants
小児の先天性心奇形は、その母親が妊娠中に特定の環境有害物質混合物に曝露したことと関連がある可能性がある、との研究結果が2013年American Heart Association's Scientific Sessionsで発表された。研究者らは先天性心奇形発現率パターンとカナダのAlberta地方の環境有害物質の存在について調査した。彼らは3つの化学物質カテゴリーを観察したが、先天性心奇形発現率と強力に関連したのはたった1つのグループだけであった。このグループの化学物質は有機化合物と金属（すなわち、ベンゼン、ブタジエン、二硫化炭素、クロロホルム、エチレンオキサイド、ヘキサクロロベンゼン、テトラクロロエタン、メタノール、二酸化硫黄、トルエン、鉛、水銀およびカドミウム）の混合物からなっていた。カナダにおいては先天性心奇形発現率は2006年以降減少しており、この減少は主に中隔欠損および円錐動脈管奇形の減少によるものである。AHAで発表された予備的な結果から、排気ガスが減少すると先天性心奇形の発現率も低下することが示唆された。研究者らは、このスタディは先天性奇形に対する環境汚染の影響に関するエビデンスを増加させたことに注目すべきである、と述べている。このスタディの限界は、個人のリスクおよび政府が毎年モニターし収集している企業の自己申告データではなく、グループレベルでの観察であることである。
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Children's congenital heart defects may be associated with their mothers' exposure to specific mixtures of environmental toxins during pregnancy, according to research presented at the American Heart Association's Scientific Sessions 2013.

Congenital heart defects occur when the heart or blood vessels near the heart don't develop normally before birth. Defects may be caused by chromosomal abnormalities, but the cause is unknown in most cases.

Researchers examined patterns of congenital heart defects incidence and presence of environmental toxicants in Alberta, Canada. The ongoing research seeks to determine if pregnant women's proximity to organic compounds and metals emitted in the air impacts the risk of heart defects in their children.

"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 septal defects and 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 that is monitored and collected annually by government, according to Ngwezi.

Co-authors are Lisa K. Hornberger, M.D.; Brad Saretsky, B.Sc.; Sujata Chandra, M.D., M.Sc.; Deborah Fruitman, M.D., F.R.C.P.C.; and Alvaro Osornio-Vargas, M.D., Ph.D. Author disclosures are on the abstract.

The study was funded by the Women and Children's Health Research Institute, University of Alberta; Hamilton-Naki Foundation of South Africa; and an Emerging Research Team Grant from the University of Alberta's Faculty of Medicine and Dentistry and Alberta Health Services.