Exposure to pesticides can cause boys to hit puberty earlier, a shocking new study finds.
Scientists say boys with a 10 percent increase of the chemicals in their body were up to 110 percent more likely to be in an advanced stage of puberty.
The pesticides increase levels of hormones that spur the production of testosterone.
Previous research has shown that early puberty increases the risk of diseases in adulthood, such as testicular cancer in men and breast cancer in women.
Early puberty also can stunt growth and cause behavioral problems.
Researchers at Zhejang University, in Hangzhou, China, looked at a class of pesticides called pyrethroids that account for more than 30 percent of global insecticide use.
Pyrethroids are used indoors and outdoors to kill mosquitoes and other insects, and are sprayed on crops. Humans are most likely exposed to them from food and residential use.
‘Residues of this pesticide are often found in vegetables, in milk and in baby food,' said lead investigator Dr Jing Liu, an associate professor at Zhejiang University.
Evidence of recent exposure to the chemical appears in human urine as a metabolite, or molecule, called 3-phenoxybenzoic acid (3-PBA).
The metabolite is known to be an endocrine-disrupting chemical that interferes with the body's hormones.
The researchers studied more than 460 Chinese boys between the ages of 9 and 16.
SEXUAL ABUSE ACCELERATES PUBERTY IN KIDS
Abuse accelerates the physical growth and maturity of children, a new study warns.
Scientists say that young girls who are emotionally and physically abused hit puberty eight to 12 months earlier than their non-abused peers.
The study, conducted at Pennsylvania State University, compared the pubescent trajectories of 84 females with a sexual abuse history and 89 of their non-abused counterparts.
Researchers found that girls with histories of sexual abuse were far more likely to transition into high puberty stages earlier than the girls who weren't abused.
Sexual abuse in particular forces children to physically mature at a faster rate.
Premature physical development such as this has been linked to breast and ovarian cancers due to the increased exposure to the hormone estrogen over a longer period of time.
They found that a 10 percent increase in 3-PBA was associated with a four percent increase in the boys' levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
Both of these hormones spur production of testosterone in males.
Having increased levels of 3-PBA in urine raised the odds of a boy being at an advanced stage of genital development by between 73 and 110 percent.
On average, boys mature between the ages of nine and 14, according to the Hormone Health Network.
Experts believe that many factors, including environmental toxins, are responsible for the trend of both girls and boys going through puberty earlier.
‘We recognize pyrethroids as a new environmental contributor to the observed trend toward earlier sexual maturity in boys,' Dr Liu said.
However, the researchers have not clearly stated how often boys would have to be exposed or how they can avoid exposure to high levels of the pesticide.
Because it's difficult to test the cause of environmental risk factors in humans, the researchers used animals to identify how pyrethroids alter the timing of puberty.
They exposed male mice to cypermethrin, a widely used pyrethroid insecticide, at the levels that were present in humans – and observed an accelerated onset of puberty.
Dr Liu said the cypermethrin had a direct effect by inducing testosterone formation and interfering with intracellular processes that are critical to male sexual development.
‘This is the first study to provide evidence that environmental exposure to pyrethroids…is associated with measurable effects on male pubertal development,' she said.
‘Given the growing use of pyrethroid insecticides, we must prudently assess these chemicals for their risks to children's health.'