Chemicals in shampoo and perfumes may cause early puberty in girls

Henrietta Strickland
December 6, 2018

Chemicals found in lipstick, nail varnish and deodorant could be causing early puberty in girls, a long running study of mothers and their daughters suggests.

They then tracked onset of puberty and found exposure to certain chemicals was linked to the early onset of puberty in girls but no evidence that chemical exposure affected boys.

"There has been considerable concern about why girls are entering puberty earlier and hormone disrupting chemicals like the ones in personal care products that we studied have been suggested as one possible reason", said lead study author Kim Harley, associate director of the Center for Environmental Research and Children's Health at the University of California, Berkeley.

"Specifically, we found that mothers who had higher levels of two chemicals in their bodies during pregnancy - diethyl phthalate, which is used in fragrance, and triclosan, which is an antibacterial agent in certain soaps and toothpaste - had daughters who entered puberty earlier".

Although Doctor Harley has acknowledged other elements can play its part on early puberty, she fears the impact this will have on children's mental health.

Youngsters also started their periods early after being exposed to methyl paraben - a chemical that is found in high street body lotions and hand creams. Researchers also find a link between these chemicals and the increased incidence of diseases such as cancer and autoimmune diseases.

Reference Association of phthalates, parabens and phenols found in personal care products with pubertal timing in girls and boys.

The vast majority - more than 90 percent - of urine samples of both mothers and children showed detectable concentrations of all three classes of chemicals, with the exception of triclosan which was present in approximately 70 percent of samples.

The researchers found that every time the concentrations of diethyl phthalate and triclosan in the mother's urine doubled, the timing of developmental milestones in girls shifted approximately one month earlier.

The chemicals they were exposed to are believed to affect the female sex hormone oestrogen, triggering adolescence early.

For the study, the researchers enrolled pregnant women of mostly Latin heritage between the years 1999-2000, living below the poverty threshold, without a high school diploma.

Most had no high school diploma and lived below the U.S. federal poverty threshold.

Prof Harley said: "But we always knew we would have the opportunity to examine other chemical exposures". However, it is unclear if the chemicals were causing the shift, or if girls who reached puberty earlier were more likely to start using personal care products at younger ages, Harley said.

Dr Harley concluded: "This is still an active area of research and more studies are needed".

The study, published in the journal Human Reproduction, examined chemical levels including phthalates, parabens and phenols. This means journalists are losing the ability to hold the rich and powerful to account. If you can, please show your appreciation for our free content by donating whatever you think is fair to help keep TLE growing.

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