Exposure to chemicals found in a wide array of personal care products has been linked to early puberty among girls, a new investigation warns.
The issue centers on specific chemicals including phthalates, parabens and phenols. They're found in an array of products, including perfumes, soaps, shampoos, nail polish, cosmetics, toothpaste, lipstick, hairsprays and skin lotions -- to name just a few.
These chemicals "get into our bodies either by absorption through the skin, by being inhaled, or being ingested [like lipstick]," explained study author Kim Harley. "Once they are in the body, they are quite quickly metabolized and [then] excreted in urine."
Harley is associate director of the Center for Environmental Research and Children's Health at the University of California, Berkeley.
As to how routine exposure to the chemicals might affect puberty, she said they've "been shown to mimic estrogen in certain laboratory conditions."
In fact, prior animal studies have suggested that exposure can throw puberty timing out of whack, Harley said.
Now, her team found that "the higher the levels of the chemicals in mothers' or daughters' bodies, the earlier the puberty" among girls. No such link was found for the timing of male puberty, however.
"We were a little surprised that the associations were only with girls and we didn't see much with boys," Harley said. "But since these tend to be estrogenic chemicals, it makes sense that they might impact girls."
To explore the issue, investigators analyzed data collected in a study that enrolled pregnant women between 1999 and 2000. The women had blood tests twice throughout their pregnancy, and interviews were also conducted to gauge exposure to the chemicals in question.
Nine in 10 of all the urine samples taken from the expectant moms tested positive for chemicals that fall into one of the three chemical classes of concern, with slightly lower percentages (about seven in 10) with respect to a chemical called triclosan. An antimicrobial, triclosan was banned for use in soap by the U.S. Food and Drug Administration in 2017, but it can still be found in some toothpastes, the researchers noted.