Exposure to 'everyday chemical' associated with higher incidence of childhood cancer: study

A new study from the University of Vermont Cancer Center links medication-associated phthalates to a higher incidence of childhood cancer. (Creative Commons: hitthtatswitch)

Researchers have linked a common chemical to higher incidence of specific childhood cancers including lymphoma, in a study that looked at nearly 1.3 million children.

Pthalates, a group of chemicals that are part of what makes plastic durable, are so common in our manmade products that they are sometimes called the “everyday chemical”.

But apart from being used in countless consumer goods, they can also be used in medications as an inactive ingredient that aids with delayed or extended drug release. This results in a higher exposure to phthalates than the background exposure that comes from handling plastic in day to day life.

A study published in the Journal of the National Cancer Institute in February, which researchers say is the first of its kind, focused on childhood exposure to phthalates through medication.

Researchers looked at records on all live births in Denmark between 1997 and 2017, and found that out of 1.27 million children, 2,027 had later been diagnosed with a childhood cancer.

The study then looked at whether phthalate exposure through medication during the gestational and childhood period was associated in any way with the incidence of cancer among these 2,027 children.

What they found was that while the use of medication with phthalates during the gestational period appeared to have no impact, childhood exposure to phthalates through medication was associated with a 20 per cent higher rate of childhood cancer overall.

“These results add to a growing body of evidence suggesting that these ubiquitous chemicals have a negative impact on human health,” Thomas Ahern, an associate professor at the University of Vermont’s Larner College of Medicine and lead investigator of the study, said in a press release.

“Our study characterized phthalate exposure based on prescription fills for phthalate-containing medications. While such exposures are typically much higher magnitude than what we would call ‘background’ environmental exposure, our findings warrant concern.”

There were two specific cancers that seemed to be associated with the phthalate exposure, the study found. The rates of osteosarcoma diagnosis in children before the age of 19 were three times higher when phthalate exposure was present, and the incidence of lymphoma diagnosis doubled.

Osteosarcoma is a bone cancer that most often affects children. Although prognosis differs depending on numerous factors, according to Cancer Research UK, around 40 per cent of people survive the cancer for five or more years after diagnosis.

Lymphoma is a cancer of the blood, and while it has a higher survival rate than some other cancers, depending on whether it is Hodgkin or non-Hodgkins lymphoma, it can lead to more complication further down the line for patients.

Researchers did not find an association between phthalate exposure and incidence of Burkitt lymphoma, a rarer form of non-Hodgkin lymphoma.

Frances Carr, a University of Vermont Larner College of Medicine professor and American Association for the Advancement of Science fellow, stated in the release that part of this could be connected to the growing understanding that phthalates are endocrine interrupters that can interfere with the hormonal systems and potentially disrupt thyroid function.

“Although more studies are needed, exposure to phthalates has been linked to thyroid, breast, and other solid tumors,” Carr, who was not involved in the study itself, stated. “Phthalates, like other plasticizers such as bisphenol A (BPA), are ubiquitous in the environment; age of exposure, as well as chronic low dose exposures, are significant risk factors for adverse health effects.”

Researchers said that more studies are necessary to identify why phthalates might be associated with increased cancer incidence, and what mechanisms could be driving this in order to cut down on risk.

“While no direct correlation has been made between phthalates in our region and increased cancer risk, this study highlights the importance of environmental exposures and their relationship to cancer risk,” Randall Holcombe, University of Vermont Cancer Center director, said in the release.

“Ultimately, research like this will lead to a better understanding of how to mitigate the risks of environmental phthalates.”