Puberty, usually occurring during adolescence, is when kids develop physically and emotionally into young men and women. Usually, this starts to happen no earlier than about 7 to 8 years of age for girls and 9 years of age for boys (the average age is about 10 for girls and 12 for boys).
Studies Show It Is Happening Sooner
Precocious puberty — the onset of signs of puberty before age 7 or 8 in girls and age 9 in boys — can be physically and emotionally difficult for kids and can sometimes be the sign of an underlying health problem. Precocious puberty currently affects 1 in 5,000 children and is 10 times more common in girls. Statistics indicate that girls in the United States are maturing at an earlier age than they did 30 years ago and the number of girls with diagnosed precocious puberty is on the rise.
In girls, the telltale signs of precocious puberty include any of the following before 7 or 8 years of age:
- breast development
- pubic or underarm hair development
- rapid height growth — a growth "spurt"
- onset of menstruation
- acne
- "mature" body odor
- enlargement of the testicles or penis
- pubic, underarm, or facial hair development
- rapid height growth — a growth "spurt"
- voice deepening
- acne
- "mature" body odor
Black and Hispanic girls continue to mature faster than white girls, on average. Nearly one-quarter of black girls and 15 percent of Hispanic girls had entered puberty by age 7, according to the new study, which appears in the journal Pediatrics.
But the trend toward earlier puberty is not as pronounced among blacks as it is among whites, the researchers say. Although the rate of early puberty among black girls in the study (23 percent) was higher than that observed in the early 1990s (15 percent), the increase was not statistically significant.
"White girls are catching up," says Dr. Frank Biro, M.D., the lead author of the study and the director of adolescent medicine at Cincinnati Children's Hospital.
Causes Of Early Puberty
Experts aren't sure what's behind the increase in earlier puberty, but it's likely due to a combination of factors, including the childhood obesity epidemic and substances in the environment.
Between 2004 and 2006, Biro and his co-authors assessed the breast development of more than 1,200 girls ages 6 to 8 in three major U.S. cities (New York, Cincinnati, and San Francisco). The stage of development in which a girl's breasts begin to "bud" is considered the onset of puberty, not her first menstrual cycle.
More than 10 percent of white 7-year-old girls in Biro's study had reached a stage of breast development marking the start of puberty, compared to just 5 percent in a similar study conducted in the early 1990s.
The average age of the first period has declined as well, says Nickel. "Girls used to get their first menstrual period at 14 or 15," she says, but now the average is closer to 12.
Regardless of their race, girls with a higher body mass index (BMI) -- a ratio of height to weight -- tend to mature sooner, the researchers found. This finding, which has been reported in other studies, suggests that soaring obesity rates among children may be contributing to the rates of early puberty.
But it's not yet clear why girls -- and especially white girls -- are starting to physically mature at younger ages. One theory is that excess body fat affects the levels of hormones that trigger puberty.
Girls who are overweight are more likely to enter puberty early than thinner girls, and the ties between obesity and puberty start at a very young age. As Emily Walvoord of the Indiana University School of Medicine points out in her paper “The Timing of Puberty: Is It Changing? Does It Matter?” body-mass index and pubertal timing are associated at age 5, age 3, even age 9 months. This fact has shifted pediatric endocrinologists away from what used to be known as the critical-weight theory of puberty — the idea that once a girl’s body reaches a certain mass, puberty inevitably starts — to a critical-fat theory of puberty.
Researchers now believe that fat tissue, not poundage, sets off a feedback loop that can cause a body to mature. As Robert Lustig, a professor of clinical pediatrics at the University of California, San Francisco’s Benioff Children’s Hospital, explains, fatter girls have higher levels of the hormone leptin, which can lead to early puberty, which leads to higher estrogen levels, which leads to greater insulin resistance, causing girls to have yet more fat tissue, more leptin and more estrogen, the cycle feeding on itself, until their bodies physically mature.
Chemicals in the environment -- most notably bisphenol-A (BPA), which is found in many hard plastic products -- may affect hormones as well, says Dr. Gary Berkovitz, M.D., a professor of pediatric endocrinology at the University of Miami's Miller School of Medicine.
Animal studies show that the exposure to some environmental chemicals can cause bodies to mature early. Of particular concern are endocrine-disrupters, like “xeno-estrogens” or estrogen mimics. These compounds behave like steroid hormones and can alter puberty timing. For obvious ethical reasons, scientists cannot perform controlled studies proving the direct impact of these chemicals on children, so researchers instead look for so-called “natural experiments,” one of which occurred in 1973 in Michigan, when cattle were accidentally fed grain contaminated with an estrogen-mimicking chemical, the flame retardant PBB. The daughters born to the pregnant women who ate the PBB-laced meat and drank the PBB-laced milk started menstruating significantly earlier than their peers. A 20-year study found that the greater the prenatal level of the hormone disruptor polychlorinated biphenyl (PCBs), the heavier the girls were at age fourteen and their puberty was statistically earlier.
Animal studies show that the exposure to some environmental chemicals can cause bodies to mature early. Of particular concern are endocrine-disrupters, like “xeno-estrogens” or estrogen mimics. These compounds behave like steroid hormones and can alter puberty timing. For obvious ethical reasons, scientists cannot perform controlled studies proving the direct impact of these chemicals on children, so researchers instead look for so-called “natural experiments,” one of which occurred in 1973 in Michigan, when cattle were accidentally fed grain contaminated with an estrogen-mimicking chemical, the flame retardant PBB. The daughters born to the pregnant women who ate the PBB-laced meat and drank the PBB-laced milk started menstruating significantly earlier than their peers. A 20-year study found that the greater the prenatal level of the hormone disruptor polychlorinated biphenyl (PCBs), the heavier the girls were at age fourteen and their puberty was statistically earlier.
One concern, among parents and researchers, is the effect of simultaneous exposures to many estrogen-mimics, including the earlier mentioned compound BPA. Ninety-three percent of Americans have traces of BPA in their bodies. BPA was first made in 1891 and used as a synthetic estrogen in the 1930s. In the 1950s commercial manufacturers started putting BPA in hard plastics. Since then BPA has been found in many common products, including dental sealants and cash-register receipts. More than a million pounds of the substance are released into the environment each year.
Family stress can disrupt puberty timing as well. Girls who from an early age grow up in homes without their biological fathers are twice as likely to go into puberty younger as girls who grow up with both parents. Some studies show that the presence of a stepfather in the house also correlates with early puberty.
Evidence links maternal depression with developing early. Children adopted from poorer countries who have experienced significant early-childhood stress are also at greater risk for early puberty once they’re ensconced in Western families.
Evidence links maternal depression with developing early. Children adopted from poorer countries who have experienced significant early-childhood stress are also at greater risk for early puberty once they’re ensconced in Western families.
Bruce Ellis, a professor of Family Studies and Human Development at the University of Arizona, discovered along with his colleagues a pattern of early puberty in girls whose parents divorced when those girls were between 3 and 8 years old and whose fathers were considered socially deviant (meaning they abused drugs or alcohol, were violent, attempted suicide or did prison time). In another study, published in 2011, Ellis and his colleagues showed that first graders who are most reactive to stress — kids whose pulse, respiratory rate and cortisol levels fluctuate most in response to environmental challenges — entered puberty earliest when raised in difficult homes. Evolutionary psychology offers a theory: A stressful childhood inclines a body toward early reproduction; if life is hard, best to mature young. But such theories are tough to prove.
Researchers know there’s a relationship between pubertal timing and depression, but they don’t know exactly how that relationship works. One theory is that going through puberty early, relative to other kinds of cognitive development, causes changes in the brain that make it more susceptible to depression. As Elizabeth Sowell, director of the Developmental Cognitive Neuroimaging Laboratory at Children’s Hospital Los Angeles, points out, girls in general tend to go through puberty earlier than boys, and starting around puberty, girls, as a group, also experience more anxiety and depression than boys do.
Julia Graber, associate chairwoman of psychology at the University of Florida, offers a broader hypothesis, perhaps the best understanding of the puberty-depression connection we have for now. “It may be that early maturers do not have as much time as other girls to accomplish the developmental tasks of childhood. They face new challenges while everybody else is still dealing with the usual development of childhood. This might be causing them to make less successful transitions into adolescence and beyond.”
Julia Graber, associate chairwoman of psychology at the University of Florida, offers a broader hypothesis, perhaps the best understanding of the puberty-depression connection we have for now. “It may be that early maturers do not have as much time as other girls to accomplish the developmental tasks of childhood. They face new challenges while everybody else is still dealing with the usual development of childhood. This might be causing them to make less successful transitions into adolescence and beyond.”
A girl's experience in infancy and even in the womb may also contribute to earlier puberty, according to a study that appeared in the journal Pediatrics. According to that study, above-average weight gain during infancy and when their mothers had their first period were contributing factors to when girls entered puberty.
In that study, which included about 4,000 girls in the United Kingdom, researchers from the Centers for Disease Control and Prevention found that mothers who had their first period before age 12, smoked during pregnancy, and were pregnant for the first time had daughters who entered puberty sooner than other girls.
Video Link --> Girls Becoming Women Sooner
Clearly, researchers have found many possible causes but not one that is definable as the main antagonist in early puberty. More research is needed.
Health Risks of Early Puberty
"Breast cancer is such a common problem, so if we can find some of the things that make it more likely, we could improve screening of those early developers," says Dr. Susan Nickel, M.D., an assistant professor of pediatrics at the Texas A&M Health Science Center College of Medicine, in Temple. (Nickel was not involved in the new research.)
Dr. Carlos Sonnenschein of the Tufts University School of Medicine warns that "the length and amount of exposure to estrogen is one of the most significant risk factors in breast carcinogenesis. Unless you are exposed to estrogens, you don't get breast cancer. The longer the exposure is, the higher the incidence. Therefore, if you decrease the age of the first menstruation, you are at higher risk".
Cancer risk isn't the only concern surrounding early puberty. Early development in girls has been linked with poor self-esteem, eating disorders, and depression, as well as cigarette and alcohol use and earlier sexual activity.
"If an 11- or 12-year-old girl looks like she's 16, people will interact with her as if she were 16," Biro says. "Early maturation increases the rate of risk-taking behaviors and lowers academic performance. It doesn't mean it's going to happen, but it could."
What Can We Do About It?
While researchers do not have the exact cause identified, the contributing factors lead to a solution of reducing chemical exposure, taking steps to combat obesity and reduce stress and depression. Chemical exposure is difficult but there are small steps we can take when purchasing products for our homes. The other issues can be dealt with through nutrition and lifestyle habits.
Following nutrition recommendations can be a difficult task but these are easy. In order to combat obesity, reduce consumption of processed foods. Limit the intake of processed animal products as they more than likely were treated with hormones. High Fructose Corn Syrup and fructose in general have been shown to have a negative effect on our bodies' ability to metabolize foods. Avoiding them is helpful.
Eating whole foods, and more plant-based than animal-based is usually best. By eating more plant-based foods we limit how much cholesterol we are adding to our bodies. Eating lean sources of animal proteins is better than high fat sources such as dairy. We need to eat a variety of foods and making sure they are in their whole food form rather than processed is key getting the nutrients we need from them.
Get more sleep! Sleep aids our bodies in numerous ways including repairing our cells and keeping our metabolism running at a high rate. It also assists in our body's control and use of hormones. Physical and mental health are both inhibited by lack of sleep and this can contribute to higher rates of depression and obesity.
Finally, exercise. Similar to sleep, exercise has been shown to help us physically and mentally. Small amounts of regular exercise have been to be effective. Just like sleep, we need to begin to find time for 20-30 minutes of regular vigorous exercise.
These are habits that must be encouraged in our children. The foods that we buy and feed to them, the activities that they engage in and their future health are all dependent upon what we encourage and model for them when they are young. It is never too late though. Begin today by helping them take charge of their health so that they can live long healthy lives.
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