April 17, 2011
When a little girl starts growing breasts a year after losing her first baby tooth, her parents probably understand the situation as little as she does. And when it happens to girls across the country, and to many girls growing up in certain neighborhoods but not others, scientists struggle to explain the phenomenon as well.
Women’s bodies have always carried biological freight from one generation to the next, bearing the physical imprint of industry and environmental loss. One of the most confounding effects of environmental change is precocious puberty among girls — taking the form of an unusually young first period, early growth of pubic hair, or breast buds in the first grade — which may be tied to where families live, the products they consume, and how healthy and happy they’ll be later in life.
Various studies have suggested that the process of puberty may be influenced by exposure to a particular class of chemicals, known as endocrine disruptors, found in everyday products like water bottles, food packaging and cosmetics.
Chemistry No One Can Avoid
Endocrine disruptors change our body chemistry by altering the function of hormones, which dictate the way our bodies develop and behave. While many questions have arisen about the potential threats these chemicals pose to our health, numerous human and animal studies in recent years suggest significant, but often invidious, effects on growth, reproductive development, and, over time, risk of cancers and other diseases. An endocrine disuptor might “mimic” a pregnant woman’s natural estrogen and change the way the fetus develops, for instance. Or her shampoo could expose her every day to a chemical linked to aggressive or disruptive behavior in young children.
According to a review of environmental research by the Breast Cancer Fund, study after study has identified alarming twists in hormonal and child development — including disruptions in puberty and elevated cancer risk in some cases — that are tied to chemicals in cosmetics, building materials, detergents, vehicle exhaust and even baby formula packaging.
Whatever the health effects, no community can escape exposure to endocrine disruptors in a modern habitat, where toxins constantly mesh with the way we eat, work and play. Meanwhile, new research shows that the “body burden” of industrial chemicals also reflects and exacerbates divides of race, class and gender. Not only are endocrine disruptors increasingly pervasive among American women and girls; the consequences of this contamination tie into race and socioeconomic circumstance in ways we’re just beginning to understand.
Last year, a group of researchers published findings of a study involving more than 1,200 girls, about six to nine years old, which showed that black and Latina girls displayed signs of puberty at a younger age than white peers, some developing breasts as young as seven years old. In an examination of related data on chemical exposures, the group also found that “Hormonally active environmental agents” had “small associations with pubertal development.”
The findings reaffirmed previous studies that point to a nexus of puberty, race and chemicals in children’s bodies. While scientists stress such findings are inconclusive, the mounting evidence of the chemical connection could illuminate a hidden dimension to environmental injustice in communities of color.
According to a 2007 report by the Breast Cancer Fund, the age range of puberty has been declining for American girls in general, but the patterns differ by race. The age of the first period for black girls has consistently been slightly younger than that for whites, the report stated, and “over the course of the 20th century, age at menarche fell faster and farther for U.S. black girls than for U.S. white girls.” There has been a similar downward shift over the past 40 years for Mexican American girls. Other studies on girls in Europe did not indicate parallel trends.
Early onset puberty concerns health and community advocates because it ties into risks in every aspect of a girl’s life. Psychologically, premature adolescence may be marked by confusion, depression, unwanted sexual advances and starting to have sex before many of their peers do. Medically, early puberty is associated with various health risks, including obesity and breast cancer — issues that disproportionately impact black women.
The study published last year, which focused on girls in New York City, Cincinnati and Northern California, showed even more pronounced differences than seen in earlier studies: at age seven, nearly one in four black girls and nearly one in seven Latina girls showed breast growth, compared to only one in ten white girls. A year later at age eight, the rates of black and Latina breast development were 43 percent and 31 percent, respectively, but only 18 percent in whites. Another key set of findings by the research team, published in Environmental Health Perspectives by lead author Dr. Mary Wolff, revealed several small but notable correlations between some endocrine disruptors, particularly common phthalates, phenols and phytoestrogens, and unusual pubertal development.
Other research points to the effects of endocrine disruptors throughout a woman or child’s life cycle. In a New York City-based study at the Columbia University’s Children’s Center for Environmental Health, which tracked pregnant Dominican and African-American women over several weeks, “Phthalates were detected in 85 [to] 100% of air and urine samples.”
Sandra Steingraber, author of the Breast Cancer Fund report and a forthcoming book about toxins and environmental health, told On The Issues Magazine that her research on puberty patterns led her to conclude, “It was appropriate to see early puberty as a kind of ecological disorder, meaning that there are many contributing factors, not just any one.”
Two types of endocrine disruptors, phthalates and phenols, have attracted public scrutiny in recent years because they are ubiquitous in the environment and scarcely regulated by government.
Bisphenol A (BPA), which is found in the linings of metal cans and plastic products, has been linked in animal studies to early puberty, behavioral abnormalities and altered immune function. One study found that blacks overall had higher urinary concentrations of BPA than whites, as did people with lower incomes.
Phthalates are typically found in soft plastics, including many children’s products. Studies have linked the chemical to abnormal sexual development in animals, as well as cancer. The Environmental Protection Agency’s data indicate that blacks have especially high exposures to Mono-ethyl phthalate, commonly found in personal care products containing fragrances. A 2003 analysis of government data by the Environmental Justice and Health Union, a coalition of environmental justice groups, found that “the Black population has the greatest overall exposure to phthalates,” though certain subgroups within the white population showed extremely high exposures.
The color line keeps resurfacing in studies of the impact of hormone-disrupting chemicals that accumulate in people’s bodies, but little is known about what exactly race means here. Is it the segregation of black and white neighborhoods? Fragrances in black hair products? Exposures just from living in the vicinity of factories that make toxic products?
Dr. Frank Biro of the Cincinnati Children’s Hospital Medical Center’s Division of Adolescent Medicine, a lead researcher in the 2010 study on race and early puberty, noted that racial categories may be a proxy for complex, overlapping factors. Obesity, or socioeconomic status, for instance, may correlate with race and influence child development, and those factors. in turn, could tie into structural issues like a lack of access to fresh healthy food, or inadequate health care. “[P]art of racial differences includes genetic differences, part of what we call race are cultural issues, part of what we call race are deeply embedded in socioeconomic differences,” Biro said. “So in this country, racial differences often evoke strong emotional responses, but race involves a lot of different factors, and we just lump them into race.”
The phalanx of chemical hazards flowing through our homes and neighborhoods makes it nearly impossible to isolate any specific chemical factor in early puberty. But watchdogs say consumers and lawmakers need to act with an abundance of caution.
The New York-based advocacy group West Harlem Environmental Action (WE ACT) is keenly aware of how race complicates issues of environmental health. The group, which has historically fought air pollution and toxic dumping in urban communities of color, is now campaigning to inform community members about hazards sitting on their kitchen and bathroom shelves.
Ogonnaya Dotson-Newman, WE ACT’s senior environmental heath coordinator, said that a challenge in the group’s neighborhood outreach efforts is persuading people to take the environment into consideration when choosing beauty products, especially those marketed toward African American women, such as hair-straightening treatments. When she speaks to women in the neighborhood, she tells them, “They’re starting to show all of these links, and do you want to wait till maybe someone can actually say, you know, ‘Hey smoking causes cancer,’ or do you recognize that it’s having an impact on you now, and what are some immediate things that you can do to begin to avoid that exposure?”
But consumer activism is a thorny endeavor for low-income families because stores in poorer communities simply don’t pack their shelves with eco-friendly beauty products. The next step for WE ACT’s community-based research initiative, Dotson-Newman said, is to gather local data on product availability across different neighborhoods, which can be used to try to pressure stores to offer a greater selection of safer products in communities of color.
Chemical risks might be mitigated by individual choices, but they can never be eliminated, especially because federal environmental laws are notoriously lax on controlling or monitoring potentially hazardous chemicals, allowing the industry in many cases to police itself. Consumer groups have had more success campaigning for stronger regulation on the state and local level. Vermont and Chicago have recently barred BPA as an ingredient in children’s products like baby bottles.
In the absence of a more comprehensive chemical regulatory policy, the Breast Cancer Fund report recommended more holistic prevention measures: reducing exposure to local air pollution and toxics, along with promoting access to healthier foods and obesity-prevention programs in low-income communities.
Still, personal vigilance can’t substitute for government oversight. Dr. Ami Zota, an environmental health researcher with the Program on Reproductive Health and the Environment at University of California San Francisco, said that regulations should be reformed to reflect the latest research on exposure risk and the effects of “background susceptibility” factors, such as poverty or social stress on disadvantaged communities.
Zota added, “because we cannot shop our way out of this problem, and it is unfair to put the burden on the consumer, we need to advocate for chemical policy reform at the federal level.”
Drawing a Line on Risk
Amid all the different factors influencing puberty, scientists may never be able to parse out the exact reason little girls are becoming adults earlier than ever before. But the documented patterns of puberty, and the intersections of race, economics and everyday chemical exposures, may help communities draw a clearer line on what level of risk they’re willing to accept along with their modern lifestyle.
The long-term trend toward earlier puberty may go unnoticed in individual families; fast-developing girls may not be aware of exactly how the phenomenon affects their lives. Nonetheless, Steingraber said, “as a group, you’re just putting more rocks in the pockets of girls, giving them more things to try to overcome, when we create a society in which we have this constellation of factors that cause them to grow up so soon.”