For some time, the medical and scientific communities have recognized that puberty is hitting girls at younger and younger ages. In addition to simply adding complications to a child’s life before she’s ready to deal with them, earlier puberty also seems to carry health risks.
Many factors have been examined as possible causes, including dietary shifts, products used in food production, and environmental factors. A new study finds that a combination of hormonal changes and other factors (including stress and BMI) are associated with earlier onset of puberty.
Here’s what the study found, and what parents should know.
Stress, BMI, Progesterone, & More
A new study published in the Journal of Clinical Endocrinology & Metabolism finds that hormones (specifically progesterone, androgens, and glucocorticoids) are a factor in the earlier onset of puberty-related changes, but that stress and BMI also affect the timing. Meanwhile, higher estrogen levels were actually correlated with the later onset of some signs of puberty.
Girls who measured high on glutocorticoid hormones, BMI, and stress levels, on average, began showing physical changes in their bodies an average of 7.2 months earlier than girls who measured lower on all three factors.
While higher hormone levels alone showed a correlation with earlier puberty, the association was much stronger when stress and BMI were higher, and less prominent in girls with lower stress and BMI.
The Long-Observed Shift
Since at least the 1980s, doctors have been noticing that more and more girls are starting puberty at younger ages. At that time, The Guardian reports that medical wisdom didn’t predict the first changes until at least age 11, but Dr. Marcia Herman-Giddens noticed an unusually high number of girls under age 10 showing signs. She raised questions that led to further research, and the numbers have continued to shift since.
“Consider the statistics provided by German researchers. They found that in 1860, the average age of the onset of puberty in girls was 16.6 years. In 1920, it was 14.6; in 1950, 13.1; 1980, 12.5; and in 2010, it had dropped to 10.5. Similar sets of figures have been reported for boys, albeit with a delay of around a year.”
Researchers have since sought the cause of this earlier onset of puberty. They’ve found a variety of correlations, such as Kaiser Permanente’s 2020 research, which found that girls who do not live in a two-parent home from birth to age two are more likely to start puberty at an earlier age. (Does this possibly correlate with the new findings about stress?)
Research has also found that Black, Hispanic, and Native American girls have higher rates of early-onset puberty, and in some cases, it can be caused by a tumor on the spine or brain, injuries to the spine or brain, certain genetic changes, or other medical conditions, according to the University of Michigan Health Sparrow.
However, so far, there is no single definitive cause that researchers can pinpoint in a way that would allow prevention or correction on a population scale.
Why Does Early Puberty Matter?
Starting puberty before one’s peers can cause social discomfort and increase mental health concerns. The American Psychological Association has advised extra support in coping skills for these girls, and noted that the symptoms aren’t unique to girls who medically meet the standards for ‘precocious puberty’ (starting before age 8) but also apply to any child who begins seeing bodily changes ahead of her peer group.
“Early-maturing girls are at increased risk of a range of psychosocial problems including depression, substance use and early sexual behavior.”
The Endocrine Society (positing that chemical exposure may be a factor and calling for additional research) adds that early-onset puberty is associated with a long list of physical health problems, including “obesity, diabetes, cardiovascular disease, and breast cancer.”
What Does The New Data Mean For Parents & Daughters?
The finding that BMI and stress may play a role in early puberty onset doesn’t mean that a better diet, more mental health care, or an easier life will prevent an individual girl from starting puberty early. The study did still find correlations between higher hormone levels and early puberty onset, even in girls with lower stress and BMI, just with a less-strong connection.
It does give parents and pediatricians some new information to work with to help predict which girls may be at higher risk, though, and early intervention can help protect girls.
Treatments do exist to halt and prevent precocious puberty when diagnosed, which can include hormone therapy or finding and treating an underlying medical problem that is causing it. That means that any information that helps medical teams predict precocious puberty more clearly is information that can make kids safer.
