Common Chemicals In Toiletries May Lead To Early Puberty

September 11, 2019

Since the early 2000s, researchers have noticed a disturbing new trend in female development. Girls are entering puberty – developing breasts, pubic hair and periods – at a younger and younger age.

So what’s driving this trend? Some researchers have long suspected that hormone-manipulating chemicals are the culprit. But these chemicals don’t necessarily come from polluted water or dangerous environments. Instead, they’ve been found in products we use every day, including shampoos, cosmetics and just about every toiletries.

Now, a new study, published on Dec. 3 in the journal Human Reproduction, supports the possibility that these chemicals in personal care products are advancing the onset of puberty. In the study, public health researchers followed a group of pregnant women and their children for 13 years, regularly measuring the concentrations of three groups of chemicals in the participants’ urine. Their findings suggest that the odds that govern whether a girl reaches puberty earlier – which could have implications for physical and mental health – may be shifted even before the child is born.

In other words, chemical exposure of pregnant women may play a role.

In fact, researchers suspect that chemical exposure in the womb may influence the onset of puberty in the years after a baby is born, said study author Kim Harley, a public health researcher at the University of California, Berkeley.

But since many women have detectable amounts of these chemicals in their bodies, the question isn’t whether someone is exposed to the chemicals, but how much they are exposed to them, Hare told Live Science.

In the study, researchers looked at three so-called hormone disruptors – chemicals that interfere with the body’s hormone system. The groups included phthalates, found in fragrances; parabens, which are preservatives used in cosmetics; and phenol, which was used in antibacterial soap during the study.

Small shifts may increase
The study found that girls born to women with higher concentrations of a phthalate in their urine during pregnancy developed pubic hair earlier than girls born to women with lower concentrations of the chemical in their urine. Similarly, girls born to women with higher concentrations of phenol in their urine during pregnancy began menstruating earlier. When the researchers looked at the girls themselves, they found that nine-year-old girls with higher concentrations of parabens in their urine reached all three stages of puberty earlier than those with lower concentrations.

In general, the researchers found that the higher the exposure, the earlier puberty began. For example, each doubling of maternal phthalate levels was associated with the start of pubic hair growth about 1.3 months earlier.

This shift may not seem like much of a change. But there are multiple hormone-disrupting chemicals acting at the same time, and “it all adds up,” says Karin Michels, professor and chair of the UCLA Department of Epidemiology, who was not involved in the study.Michels has conducted similar studies and also found that these chemicals seem to accelerate puberty.

And even small changes in the timing of puberty can increase the risk of certain cancers, Harley said, noting that early menstruation is a risk factor for breast and ovarian cancer.

There are also concerns that developing too young can be difficult to cope with.” Premature development can put a lot of pressure on girls who look physically mature but are still children mentally – it changes how they’re treated in society,” Harley said.

Still, Harley said, “We need more research to make sure that what we find is true and not accidental, and that it holds up in other populations.” For example, most of the women and girls in the study lived below the poverty line, and the women worked in agriculture, where they may have been exposed to a range of other chemicals. Future research is planned to address pesticide exposure, Harley said, but there is no research showing that exposure to agricultural pesticides changes the behavior of hormone disruptors in the body, and most of the research on how pesticides affect development has been done on chemicals that are now almost completely phased out, such as DDT.

However, Michaels says that based on her own research, low-income people are typically more exposed to these hormone-disrupting chemicals than others and are also more likely to be obese – which is known to shift puberty to an earlier onset. Harley acknowledges this effect as well. More than half of the pregnant women and children in her study were overweight, Harley said, though her group accounted for that in their analysis.

As the study continues, consumers can mostly choose not to use these chemicals, Harley notes. The easiest to avoid is the phenol called triclosan, which is now only found in one brand of toothpaste. Shoppers can also look for products that are labeled “paraben-free,” she said, but phthalates will be harder to avoid because they’re often included in trade secret scents and companies aren’t always required to disclose phthalates as an ingredient.

Michels says there also needs to be more education efforts. It’s not just these chemicals, but the effects of all chemical exposures, as well as childhood obesity.Michels says mothers do what they can to help their children, but sometimes, it’s a matter of having the right information. As she points out, “It’s very important to protect children, from the time of conception and even before, because they’re not responsible for themselves.”