According to the findings of a rat research presented today at the 60th Annual European Society for Paediatric Endocrinology Meeting, constant exposure to blue light from tablets and smartphones may disrupt hormone levels and increase the risk of early puberty.
A longer time of blue light exposure was connected to the early beginning of puberty in female rats, who also had lower melatonin levels, higher levels of many reproductive hormones, and morphological changes to their ovaries. The usage of mobile devices that produce blue light has already been linked to disruptions in children’s sleep habits, but new findings suggest that there may be additional risks for foetal development and future fertility.
The increased use of blue-light emitting gadgets, such as tablets and smartphones, has been related to lower sleep quality in both children and adults. Blue light is supposed to interfere with our biological clock by slowing the rise in melatonin levels that happens in the evenings to prepare our bodies for sleep and rest. Melatonin levels are often greater in pre-puberty than in puberty, which may contribute to the delayed beginning of puberty. Puberty is a complex process that requires the synchronisation of multiple body systems and hormones.
Several recent studies have found a rise in the onset of early puberty in girls, notably during the COVID-19 outbreak.
Increased screen time, like that experienced during the pandemic limitations, may be contributing to this observed surge, as the association between blue light exposure and lower melatonin levels implies. However, assessing this in youngsters is fairly tough.
Dr. Aylin Kilinc Uurlu and colleagues from Ankara, Turkey, employed a rat model to investigate the effects of blue light exposure on reproductive hormone levels and puberty development timing. A normal light cycle, six hours of blue light, or twelve hours of blue light were given to three groups of six female rats each.
Both groups were exposed to blue light, and the first indications of puberty began considerably early in both groups. The longer the length of exposure, the sooner puberty begins.
In addition, rats exposed to blue light saw morphological changes in their ovarian tissue, decreased melatonin levels, and higher levels of two particular reproductive hormones (oestradiol and luteinizing hormone). These alterations are all consistent with the start of puberty. Rats exposed for 12 hours also exhibited some evidence of ovarian inflammation and cell damage.
We have discovered that blue light exposure, which is sufficient to change melatonin levels, is also capable of changing reproductive hormone levels and causing earlier puberty onset in our rat model, says Dr Aylin Kilinc Uurlu. Additionally, the sooner they start, the longer the exposure.
Despite the fact that Dr Aylin Kilinc Uurlu issues the following warning: “Since this was a rat study, we cannot be certain that these findings would be duplicated in children,” the data point to blue light exposure as a potential risk factor for earlier puberty onset.
Although it is challenging to simulate in rats the same levels of blue light exposure as a child using a tablet, the age at which rats reach puberty is fairly comparable to that of humans when taking into account the shorter lifespan of rats.
Female rats go through similar hormonal and ovulation changes as humans during pre-puberty and puberty. Therefore, despite the study’s limitations, these findings are in favour of future research into the potential effects of blue light exposure on hormone levels and the start of puberty in young people.
Since the cell damage and inflammatory consequences associated with prolonged blue light exposure have the potential to have long-term repercussions on reproductive health and fertility, the team plans to look into these implications.
Additionally, they will examine whether using “night light” mobile device capabilities that minimise blue light will lessen the impacts seen in the rat model.
Despite the lack of proof, Dr Aylin Kilinc Uurlu continues, “We would advise limiting the usage of blue light emitting devices in pre-pubertal children, especially at night when exposure may have the most hormone-altering effects.”
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