In her essay, "A Few Words about Breasts," Nora Ephron talks about feeling socially ostracized for being a slower developer than her adolescent peers growing up in the 1950s.1 While most of her girlfriends already had breasts, Nora still hadn't sprouted any. Back then, many girls, like Nora, suffered great shame because they were developmentally behind their junior high peers, but these days, a half-century later, girls have a different problem.
Earlier puberty is associated with increased risk of breast cancer, ovarian cancer and polycystic ovarian syndrome later in life. Girls experiencing early puberty may also be more likely to exhibit delinquent behaviors, substance abuse and sexual risk-taking.
According to a study published in Pediatrics in 2010, 15 percent of American girls now reach puberty by age seven. Among black girls, the rate is at least 25 percent at that age. And the thing is, the average age of onset seems to be headed downward, at least for white and Latina girls. The shame these days more likely comes from having breasts in second or third grade, before the pack and before being psychologically ready.
The fact that girls have been reaching puberty earlier and earlier first caused a big stir in 1996, when a paper authored by Dr. Marcia Hermann-Giddens reported that there had been a marked decline in the age of onset of puberty. That study reviewed data on over 17,000 girls nationwide, canvassing reports from 255 doctors in 65 different practices. At that time, five percent of white girls showed signs of puberty by age seven (6.7 percent had both breasts and pubic hair), and 27.2 percent of African-American females. By age eight, almost half (48.3%) of the African-American girls and 14.7 percent of the Caucasian girls in the study had started puberty. The mean age of breast development at that time was 8.87 years for white girls and 9.96 for black.
Exactly what this shift means for girls isn’t clear yet — either on a group or individual level. But there are budding concerns. For instance, studies have linked an early start to menstruation with an elevated risk of breast cancer. And other research has shown that girls who go through puberty early tend to have lower self-esteem and a poor body image. They are also more likely to engage in risky behaviors which can result in unplanned pregnancies, experts say.
The public and the medical community found the report disturbing. In fact, at the time it was released, many in the medical community adopted the "We don't like that data therefore it must be wrong" attitude. Since then, several studies have confirmed the data, but now, what disturbs the experts is the speed at which the decline in age of onset has accelerated.
"Over the last 30 years, we've shortened the childhood of girls by about a year and a half," said Sandra Steingraber, author of a 2007 report on early puberty for the Breast Cancer Fund, an advocacy group. "That's not good." In fact, the percentage of white girls showing signs of puberty by age seven has more than doubled in the 14 years since the study came out.
While the age of menstruation hasn't declined as rapidly as the age of breast development, it nevertheless has dropped steadily. Currently, the average girl starts menstruating at 12.4 years. In the middle of the 19th century, in contrast, the age of onset was typically more like 16 or 17, and it was 14.6 by 1950. Since then, it had dropped an astonishing few months every decade.
Although scientists profess some confusion about what's to blame for the sexual development afflicting the Barbie set, they suspect some of the obvious contenders that the Foundation has been writing about for years. First, there's the problem of pollution by toxins that affect hormonal systems. The water supply, for instance, has become polluted with some of the 30,000-100,000 chemicals used commercially in the US, as well as by pharmaceutical drugs and prescription hormones like HRT, birth control pills, and growth hormones for farm animals.
We've written repeatedly about the fact that various toxins in common use have estrogenic effects, particularly endocrine disrupters like BPA, which shows up in plastic water bottles, baby bottles, and the lining of many of the canned foods on our shelves. As I've noted, it's the petrochemical-based xenoestrogens in the environment that cause the greatest harm. Not only are these xenoestrogens omnipresent, they are considerably more potent than estrogen made by the ovaries -- some even potent in amounts as small as a billionth of a gram. The body can't produce enough natural progesterone to oppose the xenoestrogens, which leads to a host of severe health problems, including early puberty as well as increased risk of cancers, tumors, weight gain, depression, autoimmune deficiency, and so on.
A Puerto Rican study found that 68% of girls who went through early puberty were exposed to phthalates, another class of endocrine disrupter, compared with only three percent of girls developing normally. Perhaps the reason that boys, unlike girls, are not maturing sexually at younger ages has to do with the fact that they're more immune to the effects of these estrogenic toxins. On the other hand, there has been an astonishing increase in the number of boys born without fully descended testicals, a condition known as cryptorchidism. Still, we don't know all the effects of the toxins our kids regularly get exposed to, and few children in the developed world are completely immune, given the omnipresence of similar chemicals in the air, the soil, our food, and household products.
The rise in obesity and poor diet most likely also plays a significant role too. According to Dr. Pisit Pitukcheewanont, "Obesity would trigger you to get your puberty earlier because of the production of the sex steroid." I've noted before studies finding that the average concentration of estrogens in obese women is between 50% and 219% higher than in thin women, and the same principle would most likely hold for fat children, who now comprise more than 30 percent of all US kids. In fact, a series of studies link high BMI with higher incidence of early puberty. Studies also show a positive correlation between high consumption of animal protein and early puberty. In fact, the relationship is somewhat astounding: A recent British study found that girls who ate high quantities of meat at age seven were 75 percent more likely to start menstruating early compared to girls who had the lowest level of meat intake. But is that because of the meat itself, or the hormones fed to the meat to promote growth?
While kids in the 1950s, like Nora Ephron, might have longed for their bodies to start growing up sexually, children under the age of ten or eleven typically aren't ready, either psychologically or emotionally. In addition, early development puts them at greater risk for various problems, including increased risk of cancers, drinking, drug use, eating disorders, behavioral problems and attempted suicide, according to a 2007 report on early puberty by Sandra Steingraber. And because early puberty means that girls have estrogen in their bodies over a longer period of time they are at higher risk for developing breast and uterine cancers.
The solution advocated by some in the medical community, not surprisingly, is pharmaceutical. Girls can take hormone treatments that slow down their development. Synthetic hormones to counter synthetic hormones -- brilliant! Of course, such treatments do have certain risks and side effects, not the least of which is that the residue could end up in the drinking water supply and have who knows what effects on future generations.
A healthier solution is to do your best to get off the pharmaceutical-synthetics merry-go-round. Rather than exposing young children to yet more drugs, perhaps it makes better sense to emphasize prevention. In other words, don't let your kids gorge on meat, dairy, and sweets. Make sure they get exercise. Use filtration systems for your air and water. Avoid plastics and synthetics in your house whenever you can. And if you do all that and your daughter nevertheless needs a bra by age eight, shower her with love and support and teach her the facts of life. And, introduce her, with her pediatricians approval, to using a natural progesterone cream to balance the potential harm posed by all that excess estrogen exposure. This step is critical in counteracting the deleterious long-term effects of exposure to environmental xenoestrogens that may have triggered the premature maturation in the first place.