Health & Science
Younger Girls, Bigger Breasts: Are Chemicals to Blame?
Surprising new research on early puberty.
We’ve all heard the stories and seen the evidence: Girls are getting breasts a lot earlier than we remember from our own elementary school days. Nobody really knows why. But because girls are also getting chubbier (along with the rest of the population), that’s been the favored theory of causation. Here’s the general evolutionary scenario: If you can eat more, you can reproduce earlier. And in fact, thanks to better nutrition and less disease, the average age of sexual maturity in girls has dropped slowly but steadily, about three months per decade, since 1850.
In 1997, though, Marcia Herman-Giddens, a scientist at the University of North Carolina, noticed that the pace of advancing puberty had greatly, unexpectedly, accelerated. And that’s no longer a good or neutral thing, because girls who enter puberty on the early end of the spectrum are at greater risk for breast cancer later on. They also tend to suffer more psychological and behavioral problems such as depression and substance abuse.
In a bombshell of a paper, Herman-Giddens wrote that girls were developing breasts, sprouting pubic hair, and getting their periods one to two years younger than previously thought, with white girls getting breasts at a mean age of 9.8 and black girls at 8.8 (menstruation typically starts two to three years later). The data were controversial: European scientists weren’t finding similar changes, and the breast observations were considered subjective—how did researchers know what was a budding breast and what was a little extra fat? To the extent the paper was credited as telling a true story, the cause was again chalked up to body weight: During the last 30 years, the percentage of American girls between the ages of six and 11 who are obese has more than tripled, to 16 percent. Fat stores estrogen and triggers leptin, another hormone involved in the puberty sweepstakes. So far so clear.
But a new study out of Denmark, published last month in Pediatrics, shows that the link between early puberty and fat isn’t the whole story. And, note from Hamlet: We ignore strange things in the state of Denmark at our peril.
For starters, the new paper confirms the American findings almost exactly. Girls are getting breasts earlier, and it’s happening fast. Researchers used the exact same protocols to measure almost 1,000 girls in Copenhagen in 1991 and a second group of the same age in 2006. The girls—all white and middle class—started budding breasts a full year earlier than their counterparts just 15 years ago (the age of menstruation had advanced about four months). While that’s a stunner in itself, the real head-scratcher was that the change in girls’ body weight was minimal and couldn’t account for the difference. Nearly all the girls in both groups were relatively thin, says Dr. Lise Askglaede, the study’s principal author at the University of Copenhagen.
So if fat isn’t resetting the puberty clock, what is?
Two other leading theories have been divorce and the media. It’s been documented that girls not living with a biological father tend to mature earlier, just like elephants, believe it or not. But if anything, families are slightly more stable now than they were 20 years ago. And if girls are becoming more sexualized from the constant stream of media images, their hormone levels would also be rising, and, notably, that’s not happening. While the Copenhagen girls are growing breasts earlier (which requires estrogen), their bodies are not making any more estrogen than the first group of girls were in 1991. To Asklaede, this indicates that the estrogen must be coming from somewhere else.
“Our best suggestion is that it is something from outside,” Aksglaede says. “The main discussion is environmental factors.” Specifically, chemicals that mimic hormones, many of which girls are exposed to every day. Called endocrine disrupting compounds, or EDCs, these chemicals include the much publicized baby-bottle ingredient, BPA, as well as pesticides, compounds in cigarettes, and phthalates (a family of molecules used as aroma stabilizers in lotions and shampoos as well as a common additive in household plastics), among many others. The U.S. government does not currently test chemicals for their effects on human hormonal systems, and the European Union is only just starting to do so.
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Comments
Soy
By: lailaq | Sat, 09/12/2009 - 02:19
Soyjoy: you thank the author for mentioning soy but where is soy mentioned in this article?
Getting exercise won't stop this
By: tinyredcar | Thu, 08/27/2009 - 09:57
I ate a pretty good diet when I was a kid, and did ballet three times a week. I also rode my bike to school, and played with the other kids on my street almost every day after school. We have PE every day at my Primary School, and swimming twice a day during the summer (we were lucky enough to have a school pool, although that's pretty common in New Zealand where I grew up). I was about as active as it gets. Still, me and another girl in my class grew breasts really early. She wasn't heavy either, actually, she was skinnier than I was.
Yeah, I'm part of this trend
By: tinyredcar | Thu, 08/27/2009 - 09:49
I was a tiny skinny 11 year old back in 1990 when I grew breasts. It was obvious they were breasts, not fat - I got my first bra that year, and it was a C cup. I got my period the same year, six months after my sister, who is 3 1/2 years older than me. My parents are together, and Dad was around a lot, though he did work nights at a tv station for some of my youth. So my weight and divorce can't be blamed, I don't think.
To this day, I have very large breasts for someone with my frame - I'm a 34G/DDDD, which is pretty unusual and a difficult size to find. Though my mother and one of my grandmothers both have large-ish breasts, neither grew them early. After several years of reading about hormones and chemicals in our food and in our personal care products, I came to the conclusion that the cause must be chemicals. I also wonder whether they contribute to my severe PMS. I've tried to weed out the nasty hormone disrupters from my diet and personal care items, but it's tough. If I have a daughter, or a son, they'll be eating/using organic only, I think.
An informative and alarming
By: Usama3 | Tue, 08/18/2009 - 15:07
An informative and alarming article. BTW, fathers should be made aware of this too. I recall going to my son's middle school and being shocked that 12-14 year old girls looked like full grown women with the dimensions that make men weak in the knees- this was quite alarming. Add to this the fact that divorce rates contribute directly to lowering puberty rates should be a matter of education for every father who cares about his daughter's wellbeing. It should be noted that girls over 12 also are more susceptible to rape and sexual assault as they go through puberty.
Must read: "The Falling Age of Puberty in U.S. Girls"
By: genflen | Wed, 08/05/2009 - 14:45
The Breast Cancer Fund, the leading organization in the country that's focused solely on prevention by identifying and eliminating the environmental and other preventable causes of the disease, commissioned a report called "The Falling Age of Puberty in U.S. Girls: What We Know, What We Need to Know." In it, author and biologist, Dr. Sandra Steingraber highlight several factors for early puberty (a risk factor for breast cancer). There is much talk about EDCs, obesity and much more than what was covered in this article, which was very informative.
I encourage mothers and all women to read this free report online at www.breastcancerfund.org/puberty or request a copy at info@breastcancerfund.org. There is also an Advocate's Guide that is an excellent resource as well.
BIG Breast
By: Mark Anderson | Mon, 08/03/2009 - 07:43
i would like make an attention on this topic.Getting big breast in So earlier in child is 5% real.However left % is we can say the because of chemical , we cannot blame medicines directly because now a days there are many food that will help in improving BOOB sizes. Scams of rape at very young age etc. are because of these astonishing growth of breast in young child's. So people should try to avoid artificial foods and chemical , just be natural.
more info on sex health issues
Any chance you could do a
By: kickabout | Sat, 08/01/2009 - 11:55
Any chance you could do a report on the technical, statistical, etc. difficulties of studying the effects of environmental hormones and hormone-like compounds on human health? There's a quick line in the article that reads, "The U.S. government does not currently test chemicals for their effects on human hormonal systems, and the European Union is only just starting to do so." This makes it sound like the gov't could just decide to test and they would have all the answers. My understanding is that there isn't a good, validated method for determining the effects of, for example, BC pills in water vs. phthalates vs. a effect only seen when both are present. It's not a simple problem, and less a matter of will than a way. If it were straightforward, it wouldn't have been hard to determine whether the cause of early onset of puberty is just a function of the weight of the girl. Measuring concentrations of compounds in blood and urine, while an initial step, doesn't tell you anything about the biological effect that those compounds are having, right?
Soy Joy
By: akgirl | Wed, 07/29/2009 - 18:21
Thanks for mentioning soy and its estrogen-mimicking/simulating compounds and capabilities. I'm always amazed at the food additives that we tend to ignore. Peanut oil/products used to be in everything and with the rise of allergies (possibly due to overexposure), soy became the additive du jour. Yet there are plenty of products with soy additives that have no need. Full dairy yogurt (even low-fat) doesn't need the "additional protein" of soy. There are similar baked goods, dairy products, salad dressings, etc that list soy on the list of ingredients with no discernible explanation or benefit. Does my salad dressing need soy as the 12th ingredient?
I also agree with the water table comment. We cannot ignore the prevalence and possible consequences of methyl mercury, medicines and other chemicals in our water table.
Earlier Puberty
By: CFR | Tue, 07/28/2009 - 18:17
In addition to the hormones found in drinking water from medications, I am always amazed that soy is so rarely mentioned as a possible "culprit" in early puberty. The amount of soy consumed in energy bars, soy milk, soy oil and soy protein isolate added to a variety to products has increased dramatically over the last few decades. Soy contains plant estrogens. The American Heart Association quietly withdrew its endorsement of soy as a heart healthy product a couple of years ago but the campaign to convince us that all things soy, no matter how processed, are great for our health continues.
the actual hormones themselves
By: RansomIII | Tue, 07/28/2009 - 17:27
It is well known in environmental engineering circles that the hormones in human birth control pills which are not metabolized by the body are also not metabolized by the bacteria in the waste water treatment plants. These human hormones are now detectable in trace amounts in most major water supplies. I.e. every time you drink water you take in some female hormones. Not a lot, mind you. We are talking parts per billion levels here. Could this, in addition to the synthetic organic compounds produced by the chemical industry, be a contributing factor to the early puberty in girls?