Excessive screen time is already known to affect physical and mental health, but researchers have now found that it may also accelerate puberty and bone growth in children, raising concerns about its impact on long-term development.

Results of a recent rat study revealed that exposure to blue light, such as from smartphones or tablets, may accelerate bone growth and bone age in rats, leading to early puberty. The study presented at the European Society for Pediatric Endocrinology Meeting in Liverpool highlights how exposure to screens from a very young age affects children's height and physical maturity.

Girls typically reach their full height by the age of 14 to 16, while boys complete their growth around 16 to 18. However, with early puberty, there is a shift in these timelines, leading to a situation where children experience a rapid growth spurt much earlier than expected and a halt in growth thereafter.

The latest study investigated if blue light could be a factor that affects bone growth, bone aging, and the early onset of puberty by studying 36 rats: 18 males and 18 females. They were divided equally into three groups. Each group underwent a different light exposure: a standard light cycle, six hours of blue light, or 12 hours of blue light daily. The exposure continued until the first signs of puberty.

The researchers then noted how the light exposure affected the growth, and length of femur bones and found that those "exposed to blue light had a faster growth, particularly in their bones, and started puberty earlier compared to those in standard light conditions."

"This is the first study to show how blue light could potentially influence physical growth and development, prompting further research into the effects of modern screen exposure on children's growth," said lead researcher Dr Aylin Kılınç Uğurlu in a news release.

"As this a rat study, we cannot be sure that these findings would be replicated in children but our data suggest that prolonged exposure to blue light accelerates both the physical growth and maturation of the growth plate, leading to early puberty," Dr Kılınç Uğurlu said.

The researchers also cautioned that the increased growth is not as beneficial as it sounds, as the blue light exposure leads to long-term bone age by causing structural changes in the growth plates of the rats' bones.

"This means their bones matured too soon which could potentially cause them to be shorter than average as adults," Dr. Uğurlu warned.

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