Early puberty may be linked to chemicals commonly used in personal care products

age When a girl reaches puberty Puberty has been declining at an alarming rate in recent decades, and scientists have struggled to understand why. A new study suggests that compounds found in a variety of products, from cosmetics to fragrances to detergents and soaps, may signal certain areas of the brain that trigger the onset of puberty.

The researchers How environmental chemicals affect the brain Dr. Natalie Shaw, a pediatric endocrinologist at the National Institute of Environmental Health Sciences in Durham, North Carolina, said the study could help explain the rise in early puberty.

Extremely early puberty (before age 8 for girls and age 9 for boys) can have lasting health effects into adulthood, including increased risk of breast cancer, diabetes, and heart disease. It can also lead to shorter height for both girls and boys. A May study from the Harvard T.H. Chan School of Public Health found that 15.5% of boys are already going through puberty. Girls had early menarche — under age 11 — and 1.4% had their first period before age 9.

Scientists have previously suggested that possible causes include obesity, diet, socioeconomic status and potential exposure to substances such as phthalates that can disrupt sex hormones.

Shaw, co-lead author of the new study, acknowledged that there is a link between early puberty and being overweight in girls. “I think that plays a role, but in my practice, it's not just those who are overweight or obese who are early puberties,” she said.

While the timing of puberty may be at least partly genetic, the rapid change is “100 percent environmental,” Shaw said, which led researchers to look for compounds that kids might be exposed to on a daily basis.

If Shaw and her team find a compound that can affect when the brain signals the onset of puberty, they will also have discovered a mechanism underlying this timing change that has not previously been detectable in population studies.

The researchers combed through 10,000 compounds in libraries of approved drugs, environmental chemicals, and dietary supplements and found several that could affect the timing of puberty, but only one of them, Musk Ambrette, is the one kids are most likely to be exposed to, according to a report published in the journal Endocrinology.

The synthetic fragrance Musk Ambrette acts on puberty-related receptors in the hypothalamus, GnRH, hormone It is involved in genital maturation and the production of estrogen, testosterone, and progesterone.

Musk ambrette is widely used in cheap and counterfeit perfumes and other scented personal care products, Shaw said, but researchers note it has also been found in wastewater samples and in freshwater fish.

The researchers' next step was to test the effects of musk ambrette on human hypothalamic cells and zebrafish larvae.

The researchers found that the compound stimulated the production of GnRH in both fish larvae and human cells.

Shaw said the new study is just a first step: Future studies will look at the effects of musk ambrette on mammals such as rodents, as well as blood levels of the compound in humans, she added.

Until more is known, Shaw suggests that parents who want to prevent early puberty should check the ingredients list of any cosmetics, perfumes or household products their children may use for the presence of musk ambrette.

Dr Apisadapong Tambundit, a pediatric endocrinologist and clinical assistant professor of pediatrics at the University of California, Los Angeles (UCLA), said the new study addresses a very important topic.

But “I don't think it's as powerful as suggesting what parents can do,” she said. Phthalate esters are Early puberty was not addressed in the study.

Jasmine McDonald, an associate professor in the department of epidemiology at Columbia University's Mailman School of Public Health in New York City, said the new findings were “a great first step.”

A big strength of this study is that they didn't start with candidate compounds: Instead, the researchers kept a biological mechanism in mind and looked for compounds that might play a role.

McDonald said it's too early to consider banning or restricting the compounds based on this study alone, but families might cut back on their use of strongly scented products.

“If you need lotion, go for unscented,” says MacDonald. “In the shower, avoid scented body washes and shampoos.”