DIGITAL LIFE

Blue light from tablets and smartphones causes precocious puberty, according to scientific study

Regular exposure to blue light through tablet and smartphone use has been linked to retinal damage, insomnia and skin problems. Now, a study presented at the 60th Annual Meeting of the European Society of Pediatric Endocrinology has pointed to a new harm: the risk of precocious puberty. Conducted in animal models, the research found reduced levels of melatonin and increased levels of some reproductive hormones, as well as physical changes in the ovaries of female rats frequently exposed to this artificial light source.

According to the authors, blue light inhibits the nightly rise in melatonin levels, which prepares the body for rest and sleep. Levels of this hormone are generally higher during prepuberty than puberty, a complex process that involves the coordination of multiple organ systems.

In recent years, several studies have reported increases in the onset of precocious puberty for girls, particularly during the COVID-19 pandemic. The link between blue light exposure and reduced melatonin levels suggests that increased screen time, such as during pandemic restrictions, may be playing a role in this reported increase. However, it is very difficult to assess this in children, justify the authors, from various medical institutions in Ankara, Turkey.

Ovaries...In the study, Aylin Kilinç Uurlu's team from Ankara City Hospital in Turkey used a mouse model to investigate the effects of blue light exposure on reproductive hormone levels and the timing of puberty onset. Females were divided into three groups of six and exposed to either a six-hour normal or 12-hour blue light cycle.

The first signs of puberty occurred significantly earlier in both groups exposed to blue light, and the longer the duration of exposure, the earlier the onset of puberty. Rats exposed to this type of lighting also had reduced levels of melatonin and increased levels of specific reproductive hormones (estradiol and luteinizing hormone), as well as physical changes in their ovarian tissue, all consistent with the onset of puberty. The females in the 12-hour group also showed some signs of cell damage and inflammation in their ovaries.

"We found that exposure to blue light, sufficient to alter melatonin levels, is also capable of altering reproductive hormone levels and causing earlier onset of puberty in our model. Furthermore, the greater the exposure, the earlier the onset." , said Uurlu. However, he does have one caveat: "As this is a mouse study, we cannot be sure that these findings would be replicated in children, but the data suggest that blue light exposure may be considered a risk factor for early onset. of puberty".

Similarities...According to the researcher, the puberty time point in rats is equivalent to that of humans, if adjusted for the lower life expectancy of these animals. The hormonal and ovulation changes that occur during prepuberty and puberty in females are also comparable to those in girls.

The team plans to investigate the cell damage and inflammatory effects detected after increased exposure to blue light, as this can have long-term impacts on reproductive health and fertility. Scientists will also assess whether the filtering feature available on some mobile devices can reduce the effects seen in the mouse model.

"While the study is not conclusive, we advise that the use of blue light-emitting devices should be minimized in prepubescent children, especially at night, when exposure may have the greatest hormone-altering effects," concludes Uurlu.

by European Society of Pediatric Endocrinology