Part 1 of a 3-part series on premature puberty
Published in Sun Media, March, 2008.
Nicole began to notice the physical changes in her five-year-old daughter in quiet disbelief. Alexa’s breasts were almost fully developed, big enough to fill a girl’s training bra.
Her little girl’s scent — discernable to a mother’s senses — was noticeably changed. She was developing a down of peach fuzz on her body and her throat was curiously enlarged. She was moody and socially mature for her age, preferring the conversation of adults to the giggle of kids her own age.
“She always wanted to play with older kids,” Nicole said from her Kingston, Ont., home. “Talking to her was like talking to a 16-year-old kid.”
At a time when there’s a heightened consciousness of hormone-mimicking chemicals, and when children are increasingly sexualized by images of young, pantyless Hollywood starlets, parents and professionals alike are debating the age-old question with renewed fervour: Are children growing up too fast?
PUBERTY AT AGE 5
Alexa is a textbook case of precocious puberty, a condition in which the child enters puberty unusually early. Medically, pediatricians consider puberty to be precocious or premature when a girl develops breasts or menstruates before age eight and testicular enlargement is observed in a boy before age nine — parameters that are the subject of debate.
Four years ago, Nicole was alone in her quest for answers. She was a single mom and could find little information. Despite pleas to her family doctor, Nicole was told her concerns were all in her head.
“I remember the exact words,” she said. “There’s nothing wrong with your daughter. You need to get yourself checked out. If you don’t believe me, get another doctor.”
So she did.
Had Nicole listened to her GP, Alexa would have had her first period at age seven. It took a year for Nicole to find a doctor to take her seriously, conduct a thorough examination and put Alexa on medication that would stop the onset of premature development.
Nicole has re-evaluated Alexa’s upbringing and putting, what she believes, is two and two together.
Alexa was lactose-intolerant as a baby. From age one to four, Alexa drank about four litres of soy milk a week. Soy is high in estrogenic properties.
“I think it had a large impact,” she said. “But eight years ago you didn’t have a lot of lactose-free formulas. She was always spitting up and soy suited her the best.”
There are a dozen theories as to what causes precocious puberty: obesity; endocrine disruptors that mimic or block hormones and can be found in baby bottles, shampoos and cosmetics; the light from the TV; stress; dysfunctional families; and even living with an unrelated male or the absence of a father.
But nothing is conclusive.
“The most these studies can show is an association,” says Dr. Mark Palmert, pediatric endocrinologist at Toronto’s Hospital for Sick Children. “They’re not proof of causation.”
Experts tread with caution when asked about the divisive issue of precocious puberty, careful not to make comments that could become inflammatory. That’s because 11 years ago, a single study set off a firestorm of controversy that’s still raging today.
“This study caused us a lot of hassle for us everywhere,” says Dr. Rose Girgis, pediatric endocrinologist at Stollery Children’s Hospital in Edmonton.
THE CONTROVERSIAL STUDY
She, like many experts, is quick to reject the findings of a study in 1997 that surveyed 17,000 girls in the U.S. concluding that girls were reaching puberty on average a year earlier than 30 years ago. In the study, lead author Dr. Marcia Herman-Giddens concluded the mean age of breast development among African-American girls was nine, while for white girls it was 10 years. The study also showed that black girls were always more advanced than white girls.
Mammoth though the study was, critics pointed out that the girls were only assessed visually so that fat tissue could have been mistaken for breasts.
Nor was the survey representative of a random sampling of girls, critics charged, as all of the subjects were in the doctor’s office because they had signs of precocious puberty.
Soon, another journal article suggested lowering the age defined as precocious puberty from eight in white girls to seven, and from seven in black girls to age six in accordance with Herman-Giddens findings.
But the authors were lambasted: Lowering the norm is dangerous and could lead to overlooking serious medical reasons behind early puberty such as tumours and genetic disorders, their critics charged.
So, what’s the general consensus now?
JUST A SYMPTOM OF OBESITY?
“My guess is that most people acknowledge that the timing of puberty is decreasing, but not to alarming numbers,” said Palmert with caution. “The big debate around the world is should we be using the age of seven or eight? Independently, doctors are making their own decisions. But my guess is most people are still doing extensive evaluations of girls under eight.”
The most widely accepted link to premature puberty is childhood obesity.
“The only thing people can come up with is a parallel of obesity and earlier onset,” said Dr. Carol Huang, a pediatric endocrinologist at Alberta Children’s Hospital. “The more fat cells, the more estrogen produced.”
Take the inverse, Huang said. It’s common for female marathon runners — whose bodies are lean and carry little body fat — to lose their period for months at a time.
A 2003 study published in American Academy of Pediatrics found a drop of 2.5 months in the average age of menstruation over 25 years. Between 1963-1970 and 1988-1994 — when two nationally representative surveys of U.S. girls were carried out — the percentage of girls between ages 10 and 15 with a body mass index above the 85th percentile for age also increased from 16% to 27%.
A 2006 study following 354 girls concluded higher BMI scores in girls between age three to five or Grade 1 were associated with an earlier average age of onset.
BREAST BUDS AT FOUR
Emily was four when her mother took a second look at the little girl she had always thought was a typically chubby toddler.
Denise was getting her daughter dressed when her mother’s intuition told her something was amiss.
“She looked different than she normally did,” Denise recalled in a phone interview from Long Island.
She touched the little breast buds protruding from her four-year-old daughter’s chest. One side felt harder than the other. Thinking little of it, she was surprised at the note of urgency from her doctor when she was told to come to the office the next day.
“I was really taken aback. I thought it would be okay.” Emily, now 10, was diagnosed with precocious puberty and goes to the doctor every three weeks for a deep-muscle injection of Lupron in her thigh, a drug that suppresses development.
While the correlation between obesity and premature development may ring knee-jerk alarm bells, Palmert said the results may not be all bad.
“This could be a sign of better health,” he said. “That the general health has improved and is causing us to have earlier pubertal development ... this could be a marker of something good.”
Last month, researchers from the University of New Brunswick confirmed long-held suspicions: Synthetic estrogen from sources such as the birth control pill present in municipal wastewater can decimate wild fish populations living downstream.
Researchers conducted a seven-year study observing the effects of adding tiny amounts of estrogen into a whole-lake research facility in northwestern Ontario. Male fish exposed to estrogen became feminized, producing egg protein normally synthesized by females. In female fish, estrogen slows normal sexual maturation, including egg production.
In 1973, an estrogen-mimicking chemical accidentally contaminated cattle feed in Michigan, ending up in people’s steaks, burgers and cheese.
A study found girls exposed to the chemical in utero were starting their periods as early as age 11.6 — a year earlier than girls not exposed.
SO WHAT'S THE NORM?
While breast development may be starting earlier, the average age of menstruation in North America has remained steady at 12.5 and is usually preceded two years by breast development.
Bafflingly high rates of breast development in Puerto Rican girls as young as two led to studies examining the effects of phthalates, a chemical used to soften plastics.
Researchers found girls with premature breasts had seven times the amount of phthalates in their blood than the control group.
Environmentalists have been decrying the health hazards of endocrine-disrupting pollutants for decades, but now that climate change has captured the public’s imagination the effects of environmental chemicals have become a mainstream issue.
When an environmental group released a report damning four brand name baby bottles for leaching toxic levels of a plasticizer Bisphenol-A last month, it made the front pages.
Nicole is convinced soy milk accelerated her daughter’s pubertal development. And though they shy away from calling anything conclusive, Girgis said it’s important to take a child’s diet into consideration.
IDENTIFYING THE POSSIBLE CAUSES
Another study in Belgium examined the relationship between a derivative of the pesticide DDT and the earlier onset of puberty among children who were either adopted or emigrated from developing countries.
The girls from countries such as India and Colombia developed breasts before age eight and started their periods before age 10.
But trying to establish a link between an endocrine-disrupting chemical and early puberty is difficult because they’ve become ubiquitous in the environment, making it a near impossible task to find an unexposed control group.
“The outcome differs depending on dose, route, timing,” Palmert said. “At the current juncture, there are clear examples of people exposed to dietary elements, hormones in feed, and exposure to endocrine-disruptive chemicals. The fact that they can have an effect is known. But you can’t make conclusions on the general public.”
Denise, however, has become a convert.
“I often said I didn’t think it was environmental,” she said. “I raised all three children in the same house, in the same way. But now I’m not so sure.”
To be safe, she’s now changed her family’s lifestyle so that her three girls drink out of stainless steel containers. She doesn’t microwave foods in plastic and the family buys organic fruits, vegetables and dairy products.
Likewise, Nicole is feeding her 15-month-old baby with glass bottles. But Huang, who has daughters age two and five, said she’s not yet convinced of a causal link with endocrine-disruptors and isn’t losing sleep over using baby bottles herself.
“There is no solid proof any of these cause earlier onset of puberty.” Adds Palmert: “More research needs to be pursued in rigorous ways. But not in panic-stricken ways.”