NEW YORK––Exposure to three common chemical classes—phenols, phthalates and phytoestrogens—in young girls may disrupt the timing of pubertal development, and put girls at risk for health complications later in life, according to new research from the Mount Sinai School of Medicine (Environ Health Perspect. March 22, 2010). These hormonally active environmental agents may alter the course of pubertal development in girls, which is controlled by steroids and gonadotropins.
Researchers investigated associations of concurrent exposures from phenols, phthalates and phytoestrogens with pubertal stages in a multi-ethnic longitudinal study of 1,151 girls from New York City, Cincinnati and northern California who were 6 to 8 years old at enrollment (2004 to 2007). They measured urinary exposure biomarkers at the first visit and examined associations with breast and pubic hair development (present or absent, assessed one year later)
The data showed the three classes of chemical compounds were widely detectable in the study population, and that high exposure to certain chemicals was associated with early breast development. The strongest links were seen with phthalates and phytoestrogens, which were also among the highest exposures. One phenol, two phytoestrogens and a subset of phthalates (those found in building products and plastic tubing) were associated with later puberty. However, the phthalates found in personal products such as lotion and shampoo, especially those with fragrance, were related to earlier breast and pubic hair development.
“Research has shown early pubertal development in girls can have adverse social and medical effects, including cancer and diabetes later in life,” said Mary Wolff, professor of preventive medicine and oncological sciences at Mount Sinai School of Medicine. “Our research shows a connection between chemicals that girls are exposed to on a daily basis and either delayed or early development. While more research is needed, these data are an important first step in continuing to evaluate the impact of these common environmental agents in putting girls at risk.”
Phenols, phthalates and phytoestrogens are among chemicals known as endocrine disruptors, which interfere with the body’s endocrine, or hormone, system. They are found in a wide range of consumer products, such as nail polishes, where they increase durability, and in cosmetics, perfumes, lotions, and shampoos, where they carry fragrance. Some are used to increase the flexibility and durability of plastics such as PVC, or are included as coatings on medications or nutritional supplements to make them timed-release.
Researchers also found that body mass index (BMI) played a role in the onset of puberty. About a third of the girls were considered overweight, which is also an indicator of early breast development. As a result, some of the chemical associations differed in more or less obese girls.
Funding for the research was provided by a grant from the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health (NIH).