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A Swedish cohort study in the journal Environment International has found that women of fertile age who were exposed to high levels of perfluorinated substances (PFAS) in drinking water were significantly more likely to subsequently have a diagnosis of polycystic ovarian syndrome (PCOS) and possibly uterine leiomyoma (or uterine fibroids [UFs]), but not endometriosis.
“We learned from previous studies that PFAS can interfere with the female reproductive system, even at low exposure levels, in the general population,” said senior author Sofia Hammarstrand, MD, a resident physician of occupational and environmental medicine at Sahlgrenska University Hospital in Gothenburg, Sweden. “PFAS may therefore be an underlying cause for gynecological diseases driven by reproductive hormones.”
Because the full etiology of PCOS, UFs and endometriosis is yet unknown, “we saw a unique possibility to study these diseases,” Hammarstrand told Contemporary OB/GYN®.
In 2013, high levels of PFAS (above 10,000 ng/L) were found in the drinking water in 1 of the 2 waterworks in the municipality of Ronneby, Sweden, dominated by perfluorooctanesulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS). The contamination was from firefighting foams used at a nearby airfield.
The study’s cohort consisted of 29,106 females of all ages who had ever resided in the municipality between 1985 and 2013.
Individual exposure was assessed via the municipality waterworks distribution data linked to annual residential address data. Overall, 27% of the cohort had lived at an address with high levels of PFAS-contaminated water.
Gynecological health outcomes were retrieved from the Swedish National Patient Register.
“No studies up until now have explored the association of the female reproductive system with high exposure levels of PFAS,” Hammarstrand said.
In total, there were 161 cases of PCOS, 1,122 cases of uterine leiomyoma and 373 cases of endometriosis.
In women aged 20 to 50 years (n = 18,503), those with exposure to high levels of PFAS-contaminated water were 2.18 times more likely to have a subsequent diagnosis of PCOS and 1.28 more likely to be diagnosed with UFs than women who were not exposed to high levels of PFAS-contaminated water.
But women exposed to high levels of PFAS-contaminated water were not at an increased risk for endometriosis.
“Our results on PCOS are similar to previous studies, thus strengthening causality,” Hammarstrand said. “However, we were surprised that, in comparison to previous studies, we did not find any association between PFAS and endometriosis.”
The study is based on contamination of PFAS from firefighting foams, “which is different from previous studies,” Hammarstrand said. “For uterine leiomyoma, there are yet too few studies for comparison.”
Because of widespread contamination of PFAS and other persistent chemicals in the environment, “it is important to better understand their effects on the female reproductive system,” said Hammarstrand, who also is a PhD student in public health and community medicine at the University of Gothenburg.
The authors hope their study will lead to further international regulations of PFAS, such as the European Commission’s recent decision to ban roughly 200 PFAS substances, starting February 2023.
“We also encourage more research on PFAS and the female reproductive system, both in order to better understand the underlying etiologic mechanisms and also because these diseases can cause much harm to those affected, along with healthcare and societal costs,” Hammarstrand said.
Hammarstrand reports no relevant financial disclosures.
Hammarstrand S, Jakobsson K, Andersson E, et al. Perfluoroalkyl substances (PFAS) in drinking water and risk for polycystic ovarian syndrome, uterine leiomyoma, and endometriosis: a Swedish cohort study. Environ Int. Published online August 12, 2021. doi:10.1016/j.envint.2021.106819