Are girls growing up too fast?

Source: Best Health Magazine: May 2011

The onset of puberty for females now ranges from age eight to 13, and is typically defined as the beginning of breast development. ‘If a girl comes in at age nine with the start of breasts, that is normal,’ says Dr. Rose Girgis, a pediatric endocrinologist at Stollery Children’s Hospital in Edmonton. ‘After about two years of these first signs, parents can expect their daughters to have their first menstrual period.’

While there is no Canada-specific research, a large-scale American study in 1997 showed that the average age girls get their first period has gradually fallen over the centuries, dropping from age 17 to about age 12 today.

A 2009 study from Denmark shows that girls in Europe are also entering puberty earlier. There is research arguing that the age of puberty in boys has also come down, but not as dramatically.

The many theories

Parents, doctors and the media have floated around theories as to why girls in particular are maturing earlier: Is it hormones in some ‘of the meats we eat, products we’re exposed ‘to that contain chemicals which mimic hormones in the body (think bisphenol A, banned in Canada for use in baby bottles), the growing trend to childhood obesity, or even the early sexualization of children via the media?

In effect, each of the theories is possible, but there is no hard data to prove that any of them is the actual cause, says Dr. Mark Palmert, head of the division of endocrinology at The Hospital for Sick Children in Toronto.

‘There have been reports of isolated exposures to environmental chemicals leading to early puberty,’ says Palmert. ‘But to say that environmental exposure is widespread and that this is why girls are now starting puberty earlier is much less clear.’

Kids are exposed to environmental estrogens or endocrine-disrupting chemicals found in everything from insecticides and pesticides to nail polish, makeup, lotion and plastics. Extensive research has shown that these chemicals send signals through the estrogen pathways that can trigger early breast development and puberty in girls.

‘Have such exposures affected the pubertal development of the population as a whole? We don’t know,’ says Palmert. ‘It depends on when, how and to what extent the child has been exposed. It’s going to take a lot of good epidemiologic data to prove cause and effect, and that may be difficult because effects can depend on the route, the dose and the time of exposure.’

The cause-and-effect link is further blurred when it comes to the impact of the overt sexuality found in magazines, movies, TV and music videos. Some researchers argue that today’s kids are constantly exposed to sexual stimuli and this might somehow trigger their bodies to adapt accordingly.

‘While there is evidence that your mind can affect some systems in the body such as the immune system, there is no hard evidence that those kinds of signals are changing the timing of puberty in the general population,’ says Palmert. ‘There is less buy-in to this hypothesis.’

One of the biggest areas of concern for parents is the growing trend of obesity in children and the role it may play in early puberty. On average, girls who are overweight begin puberty earlier. Hormones released from the added fat cells could play a role in girls maturing faster. ‘Again, it may be a factor, but we don’t know how much of it is related to being overweight or if this is a definitive cause of earlier development in the general population,’ says Palmert.

The most likely cause

The good news is parents can relax: The most accepted reason for the earlier start to adulthood is better nutrition and health. ‘You need to be about 93 lb. to be able to men-struate, and in previous centuries this weight was attained later, at around 16 years of age,’ says Dr. Franziska Baltzer, director of the adolescent medicine/gynecology program of the Montreal Children’s Hospital. ‘Today, we are eating better and we’re healthier.’

In fact, historically the earlier onset of puberty in girls was not necessarily seen as ‘a bad thing. In the past, it was perceived as ‘a sign of our progress, just like people getting taller was, says Palmert. ‘More recently, as concerns about early development have increased, researchers started looking for unhealthy explanations for it, and ideas about better health and nutrition gave way to environmental issues.’

While the health consequences of earlier puberty are not clear, and more focused research is necessary, some studies have linked early puberty in girls to increased risk for self-destructive behaviours such as drug and alcohol abuse, early sexual experimentation, depression, heart disease and breast cancer. But in fact early onset of puberty in girls is rarely a cause for medical concern.

The fact is, girls tend to follow in their mothers’ footsteps when it comes to puberty, and boys in their fathers’. ‘Heredity does play a role in when a child enters puberty,’ says Girgis.

How parents can help kids

What’s the best way to help your child”and you’adapt? ‘Parents should keep in mind that puberty brings many changes’hormonal, behavioural, and some emotional confusion,’ says Ester Cole, a psychologist in private practice in Toronto and the current chair of Parenting for Life, a non-profit education program promoting positive parenting skills. ‘So children may not want to talk to you as much. It doesn’t mean they are angry with you. They are struggling’and the younger they are in the developmental stage of adolescence, the more confusing it is.

‘As parents, we have to realize that the physical, emotional and cognitive changes are all happening simultaneously and that there is no linear path of progression simply because their bodies are maturing,’ she says.

According to Cole, the best thing parents can do when puberty hits is give their kids some latitude, and listen. ‘Positive communication and reinforcement is always important. We are good at this when they are younger, but we tend to think they need it less as they get older, particularly when they look much older than they are.’

This is particularly important as children come to terms with their changing bodies. And parents need to realize that there isn’t going to be a direct line from puberty to sexual exploration, and a sudden boy-crazy/girl-crazy attitude.

‘It’s important to maintain a clear value system at home so children feel there is psychological security and a sense of acceptance while they exercise new choices,’ says Cole.

This article was originally titled "Growing up too fast?" in the May 2011 issue of Best Health. Subscribe today and never miss an issue!