Health & Wellbeing

Exposure to “everywhere chemical” linked to childhood cancer risk

Exposure to “everywhere chemical” linked to childhood cancer risk
Researchers found high exposure to phthalates increased childhood cancer risk by 20 percent
Researchers found high exposure to phthalates increased childhood cancer risk by 20 percent
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Researchers found high exposure to phthalates increased childhood cancer risk by 20 percent
Researchers found high exposure to phthalates increased childhood cancer risk by 20 percent

Exposure to phthalates, a common chemical used to manufacture thousands of everyday products, has been linked to an increased risk of childhood cancer. The new findings add to a growing body of research suggesting this pervasive chemical may cause a number of deleterious health effects in humans.

Phthalates have been dubbed the “everywhere chemical” because they are virtually impossible to avoid for anyone living in the modern 21st century world. They are generally added to plastics to make them softer and more flexible but can also be found in soaps, shampoos and medicine coatings.

A striking study published last year estimated up to 100,000 premature deaths in the United States every year could be attributed to phthalate exposure. Homing in on causal mechanisms a more recent animal study demonstrated how phthalate exposure can increase cardiovascular disease risk.

This new study, published in the Journal of the National Cancer Institute, investigated the relationship between several childhood cancers and phthalate exposure. To quantify phthalate exposure the researchers focused on medicines using phthalate coatings. Using the Danish National Prescription Registry, phthalate exposure from medications could be measured for more than one million children up to the age of 19.

Overall, childhood exposure to phthalates was linked to a 20 percent higher incidence of cancer. More specifically, phthalates were associated with a three-fold higher rate of a bone cancer called osteosarcoma and a two-fold higher rate of a blood cancer called lymphoma.

"Our study characterized phthalate exposure based on prescription fills for phthalate-containing medications," said lead investigator on the research, Thomas Ahern. "While such exposures are typically much higher magnitude than what we would call 'background' environmental exposure, our findings warrant concern.”

Prior studies have found phthalates to be strongly linked to developmental problems in children. A review article published in early 2021 from a team of neurodevelopment experts called for urgent public health reforms to remove the chemicals from a variety of consumer products.

Frances Carr, from the University of Vermont College of Medicine, said the effect of phthalates on human hormonal systems is well known. However, the relationship between the chemical and cancer is still unclear, and Carr calls for more work looking at what kinds of phthalates can be linked with cancer and what mechanisms could be driving the association.

"Although more studies are needed, exposure to phthalates has been linked to thyroid, breast, and other solid tumors,” said Carr, who did not work on this new study. “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.”

The new study was published in the Journal of the National Cancer Institute.

Source: University of Vermont Cancer Center

Did they _measure_ the phthalate levels in the children or just estimate exposure? If the latter, they might be measuring a correlation between cancer risk and lifestyles. Children who are given those drugs probably have different parent income levels and other lifestyle-affecting differences from children who don't. Maybe children who are given those drugs are also more likely to eat more junk food and spend more time in front of TVs and computers or being exposed to microwave radiation (cell phones, wifi).

It's like that old scare about powerlines causing cancer. Yes there was a correlation between cancer rates and living under the lines, but those houses were lower value due to ugly powerlines) so the correlation was between cancer risk and economic status.

This doesn't mean that phthalates aren't a cancer risk; just that the study may not be valid evidence of that. More studies with proper controls would be needed for that.
I read the study pretty thoroughly and there are a few curious things. The authors conclude "no type of gestational phthalate exposure was associated with incidence of any childhood cancer". Interestingly, their data shows a lower risk of later cancers in children born to mothers exposed to phthalates during pregnancy (average 19% lower) but they don't mention a potential protective effect of phthalates ingested during pregnancy. They do conclude a 20% higher risk of cancer for children exposed to all phthalates though they were centered around DEP and HPMCP (67% and 16% higher). Of the five phthalates, only two had 5 or more cases of cancer (of hundreds of thousands of children) so the risk factor is more credible for those two but the number of cases is so low compared to non-phthalate-exposed cases (30 compared to 1,988 and 90 compared to 1,927) that it seem more appropriate to file this under "warrants further investigation", and only for DEP and HPMCP.