By Cara Murez
Health Day Reporter
TUESDAY, November 15, 2022 (HealthDay News) — Uterine fibroids can cause uncontrolled bleeding and infertility in women, and now a new study finds an unexpected culprit: Toxic chemicals called phthalates, which are found in everything from fast food packaging to to plastic water bottles.
“We have detected the phthalate DEHP and its breakdown products at much higher levels in the urine of women who also happen to have symptomatic uterine fibroids. Then we asked whether this connection is causal. And the answer was yes,” said study author Dr. Serdar Bulun. He is Chair of the Department of Obstetrics and Gynecology at Northwestern University’s Feinberg School of Medicine in Chicago.
Up to 80% of women will develop one or more fibroids in their lifetime, and some experience bleeding, anemia, miscarriage and infertility. Most are noncancerous.
In the study, the researchers tested primary cells isolated from women’s fibroids. The researchers found that something known as MEHHP, a breakdown product of DEHP, activates a specific cellular pathway that triggers tumor growth.
While previous studies have shown a consistent association between phthalate exposure and fibroid growth, this finding explains how that happens.
DEHP is still widely used in the United States, although concerns have been raised about its effects. It is gradually released into dust and air, landing on various surfaces.
Fibroids can be found incidentally during a cesarean section or imaging, as well as discovered after symptoms appear, said Dr. Nathaniel DeNicola, Environmental Health Expert for the American College of Obstetricians and Gynecologists.
What causes these tumors in the first place is not fully understood.
It’s normal for cells to undergo preprogrammed cell death, DeNicola explained, with about 50 million cells undergoing cell death every day in most adults. If they grow instead of dying, they can cause fibroids or cancer.
DeNicola said based on this study and previous research, he believes these chemicals are likely to contribute to fibroids.
A strength of the study is the use of urine samples from actual patients rather than animal models, he noted.
“When they compared the association between fibroids and this exposure, they had the biological sample directly from the patient,” DeNicola said. “Well, that’s a strength.”
Still, this was not a randomized controlled trial that is considered the gold standard for such research.
Good news is that when the researchers looked at the association, they found a U-shaped curve, DeNicola said. At certain exposure levels, the risk was higher.
“But on the lower end, you might be looking for some grace in those exposures,” he explained. “It’s really hard to demand, say, not demand exposure to something as ubiquitous as phthalates, a chemical found in plastic and personal care products.”
But people could potentially reduce their exposure, he noted. Physicians could potentially guide patients on how to limit exposure to phthalates in the same way they do on diet.
Policymakers could also regulate personal care products, particularly beauty products, with a view to limiting racial disparities. DeNicola pointed to previous research that found products advertised to women of color had disproportionately high levels of phthalates.
For people looking for ways to limit exposure in their personal care products, look for products that specifically state they are phthalate-free, he suggested. Look for fragrance-free products rather than products labeled “fragrance-free” that may still use phthalates to bind various scents to cancel out an obvious odor. People should also avoid heating their food in plastic, DeNicola said.
“I think it would be reasonably impossible” to completely eliminate phthalates through purchases, DeNicola said, but “we want as little as possible.”
Bulun recommended staying away from plastic bottles or plastic food wrappers and using glass containers instead. And don’t use PVC products, he advised.
Policymakers can also advocate for and fund more research and legislation, as well as ban plastic bags and bottles, Bulun added.
“In my opinion, this is the most powerful area to be explored in relation to human health. This is a severely understaffed area,” he said.
It’s possible that the pathway discovered by the researchers could be targeted by new therapeutics for uterine fibroids, Bulun suggested.
Uterine fibroids need the hormones estrogen and progesterone to grow. Scientists and physicians should continue to look for alternative temporary measures with minimal side effects to help women minimize ovulation at times when they are not interested in conceiving, he said.
“Because uterine fibroids essentially don’t develop without repeated episodes of ovulatory cycles,” Bulun explained.
The results were published online on November 14 in Proceedings of the National Academy of Sciences.
The US Office on Women’s Health has more on uterine fibroids.
SOURCES: Serdar Bulun, MD, Chair, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago; Nathaniel DeNicola, MD, environmental health professional, American College of Obstetricians and Gynecologists and Obstetrician-Gynecologist, Johns Hopkins Health System, Baltimore; Proceedings of the National Academy of SciencesNovember 14, 2022, online