Published Tuesday, Nov. 25 2014, 3:04 PM EST
Last updated Tuesday, Nov. 25 2014, 3:19 PM EST
A new study suggests chemicals in sunscreen may impair men’s ability to father children, government scientists say, but other experts question whether the chemicals wound up in men’s urine from sunscreen or through another route.
The FDA has not authorized the substances – benzophenone-2, known as BP-2, and 4-hydroxybenzophenone, known as 4-OH-BP – for use in sunscreens. And BP-2 does show up as an ingredient in aftershaves, colognes, antiperspirant and other personal-care products.
“But the question it doesn’t answer is where these compounds are really coming from. They could come from a huge variety of products,” she said.
Although the chemicals that appeared to hamper men’s reproductive ability in the study are not known to be ingredients in sunscreen, scientists say they could be breakdown products of ultraviolet-radiation filters that do get used in the manufacture of those products.
Researchers from the U.S. National Institutes of Health and the New York State health department studied 501 couples from Michigan and Texas who stopped using contraceptives between 2005 and 2009 and wanted to get pregnant.
Each participant provided a single urine sample and kept daily journals on sex, menstruation and pregnancy testing, according to a report in the American Journal of Epidemiology.
Women had higher urine concentrations of each of five chemical compounds tested, the study found, but their exposures did not significantly delay pregnancy.
Among the men, however, those with the highest urine levels of BP-2 had a 30-per-cent lower chance of impregnating their partners within a year, the research found. Couples in which the man had high urine concentrations of 4-OH-BP also had significantly reduced odds of pregnancy within a year.
The researchers acknowledge that a study such as this one, with just one urine sample tested, can’t prove cause and effect.
Still, said author Dr. Germaine Buck Louis, the findings suggest certain sunscreen chemicals may impair men’s reproductive ability. At the same time, she cautioned about the need for protection from the sun’s harmful rays, to prevent skin cancers.
Louis is a senior investigator at the U.S. National Institute of Child Health and Human Development.
“Nobody should panic,” she said. “We are not recommending that people stop using these compounds. We began looking at these UV filters because of how widespread these are in the population.”
Dr. Jane Muncke, managing director of the Food Packaging Forum foundation in Zurich, Switzerland, agrees that the compounds have found their way into the environment. But she questioned how they arrive.
“In general, it is very difficult to get exposure data or information on the use of certain chemicals,” said Muncke, who was not involved with the current study.
“This study illustrates this problem well. Here important health effects from chemical exposures are documented, but knowing how to avoid these chemicals is almost impossible for people,” she said.
Muncke said BP-2 is used in food-packaging ink, which has been known to migrate into dry food from cardboard.
The other suspect chemical, 4-OH-BP, breaks down from benzophenone-3, known as BP-3 or oxybenzone, in urine, she said. Oxybenzone is widely used in sunscreen but did not significantly affect pregnancy chances in the current study.
The Environmental Working Group recommends against using sunscreen with oxybenzone. Its website says oxybenzone acts like estrogen, can trigger allergic reactions, and has been linked to health harms, including endometriosis in older women.
Dr. Shelley Ehrlich, an obstetrician-gynecologist and environmental epidemiologist at Cincinnati Children’s Hospital Medical Center whose research focuses on environmental exposures to endocrine-disrupting chemicals, said the new study “really opens our eyes and makes us think we need to be looking at this so we can better inform the public.”
Ehrlich, who wasn’t involved in the research, advises people to keep using sunscreen but to read labels and cover as much of their bodies with clothing as possible.
“There are things you can do other than slathering on sunscreen all over the place,” she said. “Still use sunscreen, but use hats and protective clothing, and wash it off once you go indoors.”