Puberty occurs three months earlier every decade.

BarcelonaWhen she was just eight years old, Lua began to complain that her breasts were hurting, and her mother, Marcela Sáenz, a nurse, noticed that she had already developed a breast bud—breast growth—which is generally the first sign of the onset of puberty in girls. "I saw that it wasn't normal, that it was too early, and we went to the Primary Care Center for an evaluation, and from there we were referred to the endocrinologist at San Juan de Dios Hospital," explains Lua's mother. There, they performed tests, including blood tests and a bone X-ray of her hand, to assess whether her growth was in line with her age. They also assessed her birth weight and development.

Half of the cases that come to endocrinology consultations are due to suspected advanced puberty like Lua's, explains Abel López Bermejo, a pediatrician specializing in pediatric endocrinology at the Josep Trueta Hospital in Girona and head of the pediatric endocrinology research group at the Institute. Advanced puberty is like normal puberty, but at a relatively early age, in girls between 8 and 9 years old and in boys between 9 and 10 years old.

It is common in girls (10-12% of girls according to the Sant Joan de Déu Hospital) and is a common reason for consultations. "We've been seeing it for years and it's increasing; it's not stable," says Lourdes Ibáñez, a pediatric endocrinologist at the Sant Joan de Déu Hospital in Barcelona. Consultations have increased by 50% in the last five years: "We've seen greater awareness since COVID. Pediatricians are more aware, and any girl who begins puberty early is referred to us so we can assess whether treatment is necessary. We are practically overwhelmed with pediatric endocrinology consultations," she adds.

Although in most cases puberty will progress normally, tests, as Lua's was, and follow-up should be performed. "We're seeing more and more girls who not only start earlier but also progress more quickly. The result is that their periods come earlier and they're shorter because if you have less time to grow, you grow less," explains Lourdes Ibáñez. After menarche (the first period), growth averages between six and seven centimeters over the next two years.

Keep track

A distinction must be made between advanced puberty and precocious puberty. Precocious puberty is when secondary sexual characteristics appear before the age of 8 in girls and before the age of 9 in boys. It is a "rare" condition that occurs in fewer than one in every 1,000 girls. On average, the normal age for breast buds to appear in girls is between 10 and 11 years. Advanced puberty, on the other hand, is "poorly defined." Some people set it at 8 to 9 years, but others at 8 to 10. There is also no agreement on whether it should be treated, although it is usually not treated, since "8 years would be the minimum normal age," clarifies this endocrinologist at Josep Trueta Hospital.

Pediatric clinics have also observed these changes. "If we used to see the appearance of breast buds at age 9, now we see them as early as age 8, a period that isn't pathological," says Anna Gatell, president of the Catalan Society of Pediatrics of the Academy of Medical Sciences of Catalonia, "but monitoring is necessary to ensure that it doesn't accelerate."

Scientific studies indicate that, globally, the onset of puberty is advancing three months every decade, especially in girls. "It's practically every generation. This means that in four generations, it has advanced practically a year. And this is not normal," says López Bermejo.

First signs

In girls, the first sign of puberty is the beginning of breast growth, which ends with the onset of menstruation. Hair growth is not considered an indicator of the onset of puberty, although it may coincide in time, since it does not depend on the ovaries but is regulated by the adrenal glands and does not determine the age of the first period. While breast growth is the first sign, it alone is not a diagnosis of puberty because in some cases it disappears, and it can be a false alarm. "Sometimes, the bud may appear and then disappear, and this is a variation of normal because the ovary is an organ that is constantly active. That's why tests must be performed to determine whether it will be progressive or not because the other sign that indicates the onset of puberty is whether it develops and increases," explains Ibáñez.

On average, it takes two years between the beginning of breast growth and the onset of menstruation. But in the case of girls whose puberty progresses rapidly, this period is shortened, and they can begin menstruating within a year. And this impacts their height. Marcela, Lua's mother, was concerned that her daughter might remain shorter. "But they saw that the girl was a height appropriate for her age and that, although her breasts had begun to grow, it wasn't necessary to halt their development, although they offered us entry into a clinical trial," she explains.

The consequences of advancing menarche are both physical and emotional. "These are young girls who are not ready to have their periods, and there is a greater risk of sexual abuse or unwanted pregnancies," says López Bermejo. There is also a greater risk of diseases associated with exposure to estrogen for longer periods, such as an increased risk of cardiovascular disease or some cancers, such as breast or endometrial cancer. Mental health consequences have also been described. "Girls who experience puberty early are at greater risk of anxiety, depression, or low self-esteem because they feel different from everyone else; no one likes being different or being the first to get their period," Gatell admits.

Overweight and obesity

The reasons why puberty occurs early are multifactorial, but being overweight and obese can accelerate it. "Body fat is what stimulates the onset of puberty, and there is a very clear connection between more fat and more stimulation to begin puberty. Note that if a girl with normal periods has anorexia, she stops having periods because this mechanism works both due to excess and deficiency," explains the endocrinologist at Trueta.

According to a 2022 study conducted in China, advanced puberty occurs in 4% of non-overweight girls and 21% of overweight girls. "It's a small percentage, but it increases a lot if you're overweight; the difference is very marked," notes López Bermejo.

According to the experts consulted, the advancement of the age of puberty has gone hand in hand with a global epidemic of overweight and obesity. "And we know that the body mass index has been increasing over the last three decades. If children accumulate more fat, they enter puberty earlier," says López Bermejo. In fact, coinciding with the COVID pandemic, there was an increase in cases, as confinement—children didn't go outside for almost two months—led to less physical activity, higher calorie intake, changes in sleep schedules, and greater screen use. "The lack of healthy habits and a sedentary lifestyle promote overweight, coupled with screen use, and it's a vicious cycle we see in consultations," says Anna Gatell. There are also genetic alterations that can contribute to the advanced onset of puberty, and weight gain can cause these to manifest.

Environment and stress are other factors that can influence them. as well as endocrine disruptors, which can alter hormonal balance. "Plastics like bisphenol A have estrogenic activity. It's a molecule that can activate estrogen receptors, just like the female hormone," says López Bermejo. But there's no sufficiently conclusive data.

To treat or not to treat?

Generally, girls with precocious puberty are given treatment—an intramuscular injection every 28 days or every three months—to slow these changes and delay menstruation to an age within the limits considered normal, thus achieving a final height consistent with their genetic height. "But after a certain bone age, and if menstruation is already occurring, it is not treated because it no longer works and has side effects," explains Lourdes Ibáñez.

In the case of advanced puberty, there is no consensus, and treatment is usually not indicated, as it is an extreme of normality. However, there are patients who are at greater risk of compromising their adult height, and in these cases, treatment may be recommended. "It's a gray area," confirms López Bermejo. "Many professionals say nothing should be done, but recent scientific evidence suggests that a distinction should be made between girls who develop well and those who do not, and puberty should also be slowed in the latter cases."

It's estimated that half of the girls won't experience complications—that is, they won't lose weight or get their period earlier—but the other half will. "And it will depend a lot on genetics, the girl's weight, and endocrine disruptors," adds López Bermejo. But this can't be generalized. Tests and monitoring must be performed before making a decision.

The challenge is to identify which of these girls will experience rapid progression, and in this regard, a clinical trial is underway between the San Juan de Dios Hospital in Barcelona and the Josep Trueta Hospital in Girona to identify epigenetic markers that can determine which girls with advanced puberty will experience rapid progression. This observational study is expected to last two years.

The option to delay or stop puberty will depend on the girl's age and the timing of the onset, explains Ibáñez. In any case, this endocrinologist emphasizes prevention and good lifestyle habits to combat overweight and obesity.