THURSDAY, Aug. 3, 2023 (HealthDay News) -- More girls started puberty before age 8 during the COVID-19 pandemic, a phenomenon called precocious puberty, researchers say.

The reasons include potential risk factors such as increased screen time and less exercise, according to a new study, published online Aug. 3 in the Journal of the Endocrine Society.

In precocious puberty, children's bodies begin changing into adult bodies too soon. These changes normally begin between age 8 and 14.

The number of girls referred to pediatric endocrinologists for precocious puberty rose substantially over the past two years, researchers found. COVID-19 has also been linked to endocrine diseases, including obesity, which can contribute to early puberty in girls.

“Our study confirms the rise in precocious puberty diagnoses during COVID-19 and identifies contributing factors such as poor eating and exercise habits, too much screen time and impaired sleep,” said study author Dr. Mohamad Maghnie, of the University of Genoa and the Giannina Gaslini Institute in Italy.

“We found an increase in weight gain among girls diagnosed with precocious puberty during the pandemic, and rapid increase in body weight is associated with advanced pubertal development," he said in a journal news release.

The researchers studied data on rates of precocious puberty from before and after the pandemic in 133 girls in Italy. They also considered the possible relationship between COVID-19 and pandemic-related lifestyle changes.

They found 72 cases of precocious puberty between January 2016 and March 2020, and 61 between March 2020 and June 2021.

Girls diagnosed with precocious puberty during the pandemic tended to have a higher BMI than girls who did not. (BMI, or body mass index, is a measure of body fat based on height and weight.) They also spent an average of two hours per day using electronic devices. About 88.5% of them stopped all physical activity.

“The role of stress, social isolation, increased conflicts between parents, economic status and the increased use of hand and surface sanitizers represent potentially further interesting hypotheses as to why early puberty is increasing in youth,” Maghnie said. “Although, the consequence of biological adaptation cannot be entirely ruled out."

More information

The U.S. National Library of Medicine has more on precocious puberty.

SOURCE: Journal of the Endocrine Society, news release, Aug. 3, 2023