Two new studies from the American Heart Association show the difficulties facing children after dealing with air pollution and childhood cancers.

Two studies presented at the American Heart Association’s Scientific Sessions this week in Dallas, Texas reveal how childhood cancer treatments and a mother’s exposure to environmental pollution can impact a child’s heart.

These two studies highlight the importance of keeping heart health at the forefront, especially with children who have health problems at a young age.

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Environmental toxins, namely those emitted during the burning of fossil fuels, have been linked to numerous conditions, including an increase in allergies, lung cancer, and rare childhood cancers.

New research shows a mother’s exposure to specific mixtures of environmental toxins may be associated with congenital heart defects in newborns.

Specifically, the culprits seem to lie in a mix of organic and metal compounds: benzene, butadiene, carbon disulphide, chloroform, ethylene oxide, hexachlorobenzene, tetrachloroethane, methanol, sulphur dioxide, toluene, lead, mercury, and cadmium.

Researchers identified these substances by examining pollutants in Alberta, Canada, and rates of congenital heart defects from 2004 to 2011. Heart defects there have slowly declined since the government tightened regulations to reduce industrial air emissions. The decrease was mainly seen in defects that cause holes in the heart and malformations in cardiac outflow, researchers said.

Researchers believe chromosomal abnormalities cause these heart conditions, but the true cause is unknown in most cases.

“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,” lead researcher Dr. Deliwe P. Ngwezi of the University of Alberta said in a press release.

“As we have observed in the preliminary results, when the emissions decrease, the rates of congenital heart defects also decrease,” Ngwezi said.

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Children who survive childhood cancers are also at a higher risk of heart and other health problems as they age, according to a study from Donald Dengel of the University of Minnesota in Minneapolis and colleagues.

Dengel’s research team examined the arteries of 319 predominantly white American children ages 9 to 18 who had survived leukemia and other cancers, and compared them with 208 siblings who hadn’t had cancer.

Children who survived cancer were more likely to have premature heart disease and a 9 percent decrease in arterial health after completing chemotherapy. However, because cancer treatment protocols differ, researchers were unable to attribute these risks to a particular aspect of chemotherapy treatment.

“Given this increased risk, children who survive cancer should make lifestyle changes to lower their cardiovascular risk,” Dengel said. “Healthcare providers who are managing chemotherapy-treated childhood cancer survivors need to monitor cardiovascular risk factors immediately following the completion of their patients’ cancer therapy.”

While cancer remains the leading cause of disease-related death among American children, the 5-year survival rate continues to increase. Between 1975 and 1977, the rate was 58.1 percent, and now it is in upwards of 83.1 percent.

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