LONDON, June 14.- Scientists around the world are increasingly concerned about evidence that girls enter puberty at a much earlier age than previous generations, according to the British BBC.
From the time they experience their first menstruation, something scientists call the age of menarche, to the beginning of breast development, these changes that mark the beginning of adolescence appear to be occurring earlier.
For example, it is estimated that American girls today begin menstruating up to four years earlier than those a century ago. In May, new data showed that while girls born between 1950 and 1969 typically began menstruating at age 12.5, this age dropped to an average of 11.9 for the generation born in the early 1990s. 2000.
The same trend has been observed around the world. South Korean scientists have described with some alarm how the number of girls showing signs of precocious puberty – either breast development or menstruation before the age of 8 – increased 16-fold between 2008 and 2020.
We’re also seeing that these decreasing ages at puberty are even more pronounced in lower socioeconomic status groups, and in ethnic minority groups, says Audrey Gaskins, an associate professor at Emory University in Atlanta. This has important implications for long-term health, the expert said.
Researchers like Gaskins are primarily concerned that the early onset of puberty could trigger a cascade of events with far-reaching consequences in adulthood. New data suggest that it may not only shorten the fertility window, especially if these women enter menopause earlier, but also shorten their lives.
Precocious puberty has repeatedly been associated with an increased risk of diseases ranging from breast and ovarian cancers, metabolic syndromes such as obesity and type 2 diabetes, and cardiovascular disease.
Scientists are still trying to understand why this happens, but Brenda Eskenazi, a professor of public health at the University of California, Berkeley, says one theory suggests that if the body’s cells are exposed to circulating levels of sex hormones such as estrogen for a longer period of time, this can increase the risk of tumor development because these hormones stimulate cell growth.
The onset of puberty is dictated by two powerful communication networks in the body known as the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes, specialists explain.
Gaskins says that until 15 years ago, scientists assumed that the only cause of premature puberty was obesity, and that proteins produced by fat cells, called adipokines, played a role in stimulating it. Instead, several studies carried out in the last three years have pointed to another, more surprising cause: air pollution.
Much of this research has been carried out by scientists in South Korea, where Seoul, Busan and Incheon are among the 100 most polluted cities in the world. A study recently published by Ewha Womans University in Seoul has detected a repeated relationship between exposure to various pollutants and earlier puberty.
Some of the main culprits appear to be toxic gases such as sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone, all released into the air through vehicle emissions or waste produced by factories.
