Associations weren’t seen among boys using parabens, phthalates.
Early life exposure to certain endocrine disrupting chemicals (EDCs) commonly found in cosmetics and other household products was linked to early puberty in girls, but less so in boys, researchers reported.
In a longitudinal cohort study of Hispanic participants, both prenatal and peripubertal exposure to parabens, phthalates, and other EDCs found in makeup and soaps were linked to early development in young girls, written by Kim Harley, PhD, of University of California Berkeley, and colleagues, in Human Reproduction.
The researchers found a twofold increase in mothers’ urine biomarker concentrations for certain chemicals during pregnancy, which was associated with a significantly earlier average onset of pubarche (first appearance of pubic hair) and menarche (first menstruation) in girls, although wasn’t tied to thelarche (first onset of breast development) (P<0.05 for all):
- Monoethyl phthalate: 1.3 month earlier pubarche (95% CI -2.5 to -0.1)
- Triclosan: 0.7 month earlier menarche (95% CI -1.2 to -0.2)
- 2,4-dichlorophenol: 0.8 month earlier menarche (95% CI -1.6 to 0.0)
However, elevated exposure to propyl paraben at age 9 was the only biomarker tied with a significantly early onset of gonadarche in boys (average 1.0 month earlier, 95% CI -1.8 to -0.1 months). None of the other environmental chemicals were tied to an earlier gonadarche or pubarche in boys.
The authors cautioned that study limitations included the fact that the children were all Latinos living in a farming community. Also, reverse causality was a possibility as children who experience early puberty may be more likely to use personal care products, they noted.
“We already suspect that certain chemicals that are widely used in personal care products — like phthalates, parabens, and triclosan — are endocrine disruptors,” said Harley in a statement, explaining that these chemicals “mimic, block, or otherwise interfere with natural hormones in our bodies, such as estrogen.”
“In laboratory studies, these chemicals have been shown to cause earlier puberty in rats, but there are very few studies in humans.