During the summer and winter holidays, the pediatric endocrinology specialty is always the busiest time of the year, with a steady stream of parents bringing their children to the clinic for “precocious puberty”. However, only a small percentage of them are finally diagnosed with precocious puberty and need treatment. On the one hand, parents are paying more and more attention to their children’s healthy development than a few years ago, and on the other hand, the incidence rate is really increasing (some news reports report that the incidence rate in Shanghai is 1%, but for the time being, we have only seen news reports and have not checked the relevant literature; the incidence rate of precocious puberty was generally considered to be 0.6% before). In the process of medical consultation, parents are most concerned about the consequences of precocious puberty and the need for treatment, but the most frequently asked question is “why?” . The answers searched on the Internet are not only varied, but also seem to be related to food: junk food such as Coke and burgers are the first to suffer; all kinds of tonic products are coming; infant milk powder is often blamed; environmental pollution is to blame …… and so on. So what exactly are the causes of precocious puberty in the eyes of pediatric endocrinologists? The causes of different types of precocious puberty are different We often divide precocious puberty into two simple categories: one is called peripheral precocious puberty, also called pseudo-precocious puberty; the other is called central precocious puberty, also called true precocious puberty. The causes of the former category are mostly clear, such as misuse of drugs, tumors that secrete sex hormones, and autonomic activation of gonads (ovaries and testes) that are not controlled by the higher nerve centers. In true precocious puberty, the situation is more complex and can be caused by other diseases (organic), but most cases are still idiopathic (i.e. no other etiology can be found). Of course, the situation varies by gender. In boys, organic diseases are the main cause of true precocious puberty, which can account for 25% to 90% of the cases, such as hypothalamic malformation tumor (which is not really a tumor), cranial trauma, central nervous system infection, radiotherapy, etc.; while in girls, the cause of true precocious puberty is mostly not found, i.e. idiopathic, which accounts for about 70% to 98%. Therefore, when you ask your doctor about the cause of precocious puberty, the answer you will probably get is “I can’t say” or “I don’t know”! The initiation mechanism of puberty is a very complex neuro-endocrine regulatory process. Even though changes in some cytokines and hormones have been found to indicate or confirm the onset of puberty, the mechanism of why these factors are characteristically altered at a certain time is not clear. Even the mechanisms of pubertal development under normal conditions have not been fully elucidated, let alone precocious puberty under abnormal conditions. These factors are associated with the occurrence of precocious puberty Although the exact cause of precocious puberty is still unclear, some factors appear to be associated with the occurrence of precocious puberty through some cross-sectional research studies. Gender: Girls are more likely to have precocious puberty. It is generally believed that the onset of central precocious puberty is about 10 times higher in girls than in boys. Of course, the results vary from study to study, but the ratio of both sexes is almost concentrated at 3:1 to 23:1 (female:male). Genetic: There is a significant genetic predisposition for pubertal development, including precocious and delayed sexual development. Early onset of menarche in the mother is generally associated with an early age of onset in the daughter. Also, mutations in certain genes have been found in some families with precocious puberty. Nutrition: The nutritional status has a very strong influence on sexual development. As the nutritional status of children in China has improved over the past 30 years, the average age of menarche for urban girls has dropped from 13.5 years in 1979 to 12.3 years in 2005. A similar situation occurred abroad: the age of puberty had been declining for 100 years until the middle of the 20th century, with improvements in living conditions thought to be the main factor. Many studies have also found an increased risk of precocious puberty in obese girls; however, no such problem has been found in boys. Intrauterine development: Many current studies have also found that if fetuses do not develop well in utero, for example, if their birth weight does not reach the appropriate standard for gestational age – medically known as small for gestational age – these children are at increased risk for certain diseases in the future, including precocious puberty, metabolic syndrome, polycystic ovaries, etc. Living environment: Foreigners have also found that the risk of precocious puberty increases 10-20 times in children adopted intercountry, and the risk of precocious puberty increases in single-parent families that lack a father. As for the reason, as usual, it is not clear. Endocrine disrupting chemicals Finally, we have to mention a very popular word in recent years – endocrine disrupting chemicals (EDCs for short), which are a large group of substances that can be said to be ubiquitous and inseparable in our lives, such as various plastic products, detergents, pesticides, etc. These substances have hormone-like effects. Because these substances have hormone-like effects or interfere with the normal action pathways of hormones in the body, they are now widely believed to be related to the occurrence of certain endocrine diseases. In the past 15 years, the United States and Europe have found that the age of breast development in girls has begun to advance, which obviously can no longer be explained by nutritional improvements, so many people have turned their attention to the role of EDCs that mimic estrogen, which include the famous bisphenol A (BPA), other substances such as the widespread use of DEHP (a plasticizer), pesticides in DDE, flame retardants polybrominated biphenyls ( PBB) and lead products, among others. Some animal experiments have also confirmed that these substances have estrogen-mimicking and anti-androgenic effects, with certain pathological manifestations, such as testicular dysgenesis in males. Some cross-sectional findings in the population vary from country to country, although most suggest an association between these substances and early breast development and early age of menarche. However, because there are so many confounding factors in these studies, there is still no unified conclusion that EDCs interfere with pubertal development, and it is still under hypothesis. In summary, precocious puberty really does not have much to do with what the child eats, unless the child is over-nourished or ingests substances containing large amounts of sex hormones, the latter of which usually occurs in accidental events, such as misuse of drugs. How to prevent Since the exact cause of idiopathic central precocious puberty is not known, it is basically impossible to talk about how to prevent it. What can be done includes 1) preventing accidents – for example, putting away contraceptive medications at home, including some topical dermatological medications (some containing corticosteroids), beauty products (especially colored cosmetics and nail polish, which contain lead); 2) eating right + exercising and not being overweight or obese; 3) reducing the exposure of infants and children to EDCs Risk, such as: do not repeatedly use plastic bottles containing beverages, because these plastic bottles are not designed to be used repeatedly, the use of too long will cause the release of plasticizers; avoid plastic products containing excessive heat or microwave heating; infants try to use glass bottles or BPA-free plastic bottles and so on. As for the rumors that frequent eating of chicken wings, foreign fast food, carbonated drinks and other so-called junk food causes precocious puberty, it is basically nonsense, unless your child eats too much fat. Of course, here is not to say that these fast food is good, although not very related to precocious puberty, but still can cause children obesity, tooth decay, bone calcium loss and other problems. Lastly, you need to stay away from all kinds of tonic products and growth promoters under various banners, whether they will cause precocious puberty or not, but your child does not need and should not be supplemented with so-called nutrition through these means. The actual fact is that you can find a lot of people who are not able to get a good deal on this.