- During the pandemic, rates of precocious puberty increased in many countries, sometimes by three-fold.
- Researchers identified possible reasons for the phenomenon, including sedentary lifestyles.
- Given the potential negative consequences of precocious puberty, these mechanisms should be further studied.
The COVID-19 pandemic disrupted people’s lives in many irreversible ways. One of the lesser-known effects was precocious puberty among children.
Precocious puberty occurs when children develop secondary sex characteristics at an extremely early age, that is, before age 8 for girls and age 9 for boys. Precocious puberty can lead to poorer physical health, including a higher risk for metabolic syndrome, a higher risk for reproductive cancers, and rapid, incomplete growth (sometimes resulting in shorter adult height). In addition, precocious puberty is associated with risky behaviors and poorer mental health, including lower self-esteem.
During the pandemic, increases in rates of precocious puberty were reported around the world. In both Turkey and Henan Province, China, three times as many cases of precocious puberty were reported in 2020 than in 2019. Given its negative consequences, Prosperi and Chiarelli (2023) identified nine potential causes of the phenomenon:
1. Sedentary lifestyle
During the pandemic, people, including children, often adopted or were forced into a sedentary lifestyle. Without access to gyms and often stuck at home, people exercised less and spent more time on electronic devices. These practices likely contributed to weight gain, which can stimulate puberty through different means including greater body fat, leptin levels, and insulin resistance.
For example, in Shanghai, China, girls who were diagnosed with precocious puberty had gained on average (median) 2 kilograms within the last six months. They were also spending more time on electronic devices and exercising less.
2. Poor diet
People tended to consume more snacks and processed food, including sugary and high-calorie foods during the pandemic. Studies found increases in not only BMI, but also glucose, glycemia, and insulin levels in children during the pandemic. These changes contributed to obesity, and thus precocious puberty, among children.
3. Sleep disturbance
Overall, adults and children experienced lower sleep quality during the pandemic. In some studies, sleep disturbances were comorbid with precocious puberty.
It is speculated that low melatonin levels, which may underlie poor sleep quality, might contribute to precocious puberty as melatonin appears to inhibit early puberty. However, more research is needed in this area.
4. Electronic devices
It is speculated that blue light from electronic devices could contribute to precocious puberty. Whereas previously, humans were mostly exposed to blue light from the sun, these days, we receive blue light exposure at night from our various electronic devices.
This exposure might inhibit the production of melatonin, which could then lead to precocious puberty. However, this research is preliminary; current studies are extremely limited and typically focus on effects on rats.
5. Vitamin D deficiency
During the pandemic, people tended to spend less time outdoors and received less exposure to the sun. Thus, rates of Vitamin D deficiency increased. Vitamin D deficiency has been tentatively linked to precocious puberty in girls.
6. Disposable plastics
Disposable items, such as plastic utensils, became more popular during the pandemic due to the prevalence of take-out and efforts to avoid virus transmission. However, these items may have an unintended consequence, exposing children to endocrine disruptors (which modify the hormonal system) such as Bisphenol A (BPA), and potentially spurring early puberty.
Many children experienced fear and anxiety because of the pandemic, potentially triggering their biological stress responses. Stress is a risk factor for precocious puberty, as explained in my prior article.
8. COVID infection
Although the mechanism is unknown, COVID-19 itself could potentially cause precocious puberty. Autopsies of people who died from COVID-19 indicated brain abnormalities, including viral spread to the olfactory bulb which is related to precocious puberty. Researchers speculate that COVID-19 could contribute to precocious puberty through inflammation of the olfactory bulb, disruption of the blood-brain barrier, or cytokine storm (when the immune system overreacts and releases too many cytokines, resulting in hyperinflammation).
9. Parental monitoring
Finally, the authors suggest a more benign reason for the increase in precocious puberty. It is possible that due to increased time at home, parents were able to monitor their children’s development more closely, and thus more readily detect precocious puberty. Therefore, the increased rates could reflect better diagnosis.
In summary, many different factors, including a sedentary lifestyle, anxiety, and COVID infection may have contributed to precocious puberty. However, the evidence for these various mechanisms is still emerging.
Nevertheless, the long-term effects of the pandemic need to be examined. Whereas people have typically focused on the effects on children’s learning and social development, there have also been irreversible biological effects—including, perhaps, the case of precocious puberty.
Prosperi, S., & Chiarelli, F. (2023). Early and precocious puberty during the COVID-19 pandemic. Frontiers in Endocrinology, 13, 1107911. https://doi.org/10.3389/fendo.2022.1107911