Endometriosis is a painful condition in which uterine tissue grows outside the uterus, and the researchers are reporting the possible link with benzophenone (BP)-type ingredients, that they say mimics the effects of the female sex hormone estrogen and increases risk of being diagnosed with endometriosis.
The study, carried out by Kurunthachalam Kannan, research scientist at the New York State Department of Health, and colleagues, was published in the American Chemical Society’s journal Environmental Science & Technology, and is the first to look into this connection.
Kannan and colleagues explain that some sunscreens and other personal care products contain benzophenone (BP)-type ingredients that are very effective in blocking potentially harmful ultraviolet rays from the sun.
The problem lies in the researchers’ claim that small amounts of BPs can pass through the skin and be absorbed into the blood, where they mimic the effects of estrogen.
Endometriosis, which affects up to 1-in-10 women of reproductive age, needs estrogen to develop. Despite those facts, scientists until now had not checked for a connection between the use of BP sunscreens and the likelihood of being diagnosed with endometriosis.
Increased diagnosis risk
In their study, the scientists analyzed BP levels in the urine of 625 women who underwent surgery for endometriosis.
They found that high levels of one BP called 2,4OH-BP were associated with an increased risk of an endometriosis diagnosis.
Women tended to have higher levels of BPs during the summer months and if they lived in sunny California, further suggesting a link with sunscreens, according to the study.
“Our results invite the speculation that exposure to elevated 2,4OH-BP levels may be associated with endometriosis," say the researchers.