Precocious puberty is a condition which causes children to begin puberty abnormally early. “Abnormally early” is generally defined as before 8 in girls and before 9 in boys. It is up to twenty times more common in girls. This condition has some serious consequences, including higher rates of behavioral and emotional disorders and shorter adult height.
There are two types of precocious puberty: central and peripheral. Central precocious puberty means the part of the brain responsible for puberty sends signals to produce the hormones that cause pubertal development, but the signals are sent unusually early. Everything except the onset of puberty is normal with CPP, so the timeline and sequence of development are roughly normal. It is often difficult to identify a specific cause of CPP.
Peripheral precocious puberty occurs when these signals are NOT being sent yet, but some sexual characteristics are developing anyways. This is because the hormones responsible for puberty are being produced from an outside source, such as a cyst or tumor. The sequence of development often occurs out of order when this is the case, so there is often an isolated aspect of development. For example, development of pubic hair may occur abnormally early without any other aspects of puberty.
Symptoms: Girls vs. Boys
In girls, precocious puberty is considered by physicians when they begin breast/pubic hair development before the age of 8 or beginning menstruation before 10 years old. It may also be considered if the child has nearly or fully developed breasts before age 9 or 10. Girls are more likely to experience precocious puberty in general, and they usually will experience central precocious puberty.
In boys, precocious puberty is considered when testicular or penile enlargement occurs before age 9. Boys rarely experience precocious puberty - but when they do, it is usually peripheral precocious puberty. These tumors release the hormones that trigger certain aspects of sexual development, resulting in isolated forms of development.
Causes
A variety of causes have been identified for central precocious puberty. One of the main causes is childhood obesity. As childhood obesity becomes more and more common, so does precocious puberty. This is because obesity almost always causes hormonal imbalances. Leptin is the hormone responsible for the feeling of being full or satisfied after a meal. People with obesity have leptin resistance, meaning they have a very high level of leptin, but their bodies do not necessarily sense that. High levels of leptin trigger the release of the hormones that set off puberty.
Another suspected cause of CPP is exposure to chemicals that disrupt the endocrine system. These chemicals include fluoride, phthalates, BPA, and parabens. Exposure to pesticides and antibiotics found in food and water are also suspected causes. Most studies indicate that exposure to these chemicals in the womb is a more significant cause for precocious puberty. It is very difficult to limit exposure to consumer chemicals, so the most effective way to prevent precocious puberty is to encourage a healthy lifestyle in childhood.
Peripheral precocious puberty does occur in girls as well, although very rarely. In girls, it is usually caused by ovarian cysts, hypothyroidism, or McCune Albright syndrome. Hypothyroidism and MAS indirectly cause precocious puberty by causing ovarian cysts that secrete puberty-triggering hormones. In boys, peripheral precocious puberty is most often caused by tumors in the testicles or adrenal glands or a genetic mutation. The testicles and adrenal glands are both responsible for pubertal development, and tumors in either of these places results in disordered hormone production. Familial Male-limited Precocious Puberty is a very rare genetic condition which causes sexual development as early as 1-5 years old.
Impacts
Precocious puberty has a variety of impacts, both physical and psychological. One of the primary physical impacts of precocious puberty is shorter adult height. Children with precocious puberty often have a shorter final height since they will stop growing earlier then their peers due to the early onset of puberty. The psychological impacts of precocious puberty are more severe, though. Adolescence is a time when one wants to fit in with their peers, so having an earlier onset of puberty may make a child feel “other”.
Women who experienced earlier onset of puberty are much more prone to depression and substance use disorders. While boys experiencing precocious puberty had lower levels of depression in adolescence than their peers who matured later, they were found to be much more likely to have increased anxiety, depression, and negative self image in adulthood. However, girls were found to be much more likely than boys to develop a full-fledged disorder.
Conclusion
Early onset of puberty, which is often caused by childhood obesity and exposure to chemicals, has a variety of impacts. It is more common in girls and also substantially more likely to have severe psychological impacts on girls. Over time, puberty has, on average, been occurring earlier and earlier. This is particularly true for girls. In the eighteenth century, the average age of the first menstruation was 17. By the 1960’s, that age was lowered to 13 due to better access to nutrition and hygiene. However, the age of puberty is still decreasing steadily due to the rise in childhood obesity. The best way to reduce the psychological impacts of precocious puberty is to prevent it altogether, which can be achieved most effectively by preventing childhood obesity.
Further reading:
Obesity and Precocious Puberty:
Chemical Exposure:
Assessed and Endorsed by the MedReport Medical Review Board