Pyrethroid pesticide exposure appears to speed puberty in boys

boy
Credit: CC0 Public Domain

Environmental exposure to common pesticides may cause boys to reach sexual maturity earlier, researchers have found. They will present their study results Saturday at the Endocrine Society's 99th annual meeting in Orlando, Fla.

Previous research shows that increases the risk of diseases in adulthood, for example, testicular cancer in men and breast cancer in women. Early puberty also can stunt growth and cause behavioral problems.

The class of pesticides studied, pyrethroids, accounts for more than 30 percent of global insecticide use, said Jing Liu, Ph.D., lead investigator and an associate professor at Zhejiang University in Hangzhou, China. These chemicals are known endocrine-disrupting chemicals that interfere with the body's hormones.

"We recognize pyrethroids as a new environmental contributor to the observed trend toward earlier in boys," Liu said.

Today, a boy's body matures into an adult's between the ages of 9 and 14 years on average, the Hormone Health Network reports. Experts believe that many factors, including environmental toxins, are responsible for the decreasing age at onset of puberty for both boys and girls.

Pyrethroids are used indoors and outdoors to kill mosquitoes and other insects, and are sprayed on crops. Humans likely receive most of their exposure to pyrethroids from food and residential use. Evidence of recent exposure to the chemical appears in human urine as a metabolite, or molecule, called 3-phenoxybenzoic acid (3-PBA).

In a study of 463 Chinese boys ages 9 to 16 years, Liu's research team found that a 10 percent increase in 3-PBA was associated with a 4 percent increase in the boys' levels of luteinizing hormone (LH) and follicle-stimulating (FSH). Both these hormones spur production of testosterone in males.

Having an increased urinary level of 3-PBA raised the odds of a boy being at an advanced stage of genital development by 73 to 110 percent, Liu reported.

Because it is difficult to test the cause of in humans, the researchers sought to identify in animals how pyrethroids alter the timing of puberty. After they exposed male mice to cypermethrin, a widely used pyrethroid insecticide, at the relevant levels that are present in humans, they observed an accelerated onset of in the mice. Liu said they demonstrated that cypermethrin had a direct effect by inducing testosterone formation and interfering with intracellular processes that are critical to male sexual development.

"Given the growing use of pyrethroid insecticides, we must prudently assess these chemicals for their risks to children's health," Liu said.


Explore further

Exposure to certain insecticides linked to childhood behavioral difficulties

Citation: Pyrethroid pesticide exposure appears to speed puberty in boys (2017, April 2) retrieved 17 October 2019 from https://medicalxpress.com/news/2017-04-pyrethroid-pesticide-exposure-puberty-boys.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
280 shares

Feedback to editors

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more