A recent scientific study shows that the bright electric exposure of pre-school children almost completely suppresses melatonin production in the evening, which is an important complement to growing research in this area. Melatonin suppression is a marker of the disruption of our circadian rhythms.
Ten children between the ages of 3 and 5 were exposed to bright light one hour before bedtime at around 8 pm (~ 1000 lux from a light box). Melatonin suppression (which stops the body from producing this hormone) began within 10 minutes and lasted another hour after the bright light was turned off at 8:00 pm, which was well within its usual sleep period. Melatonin is a hormone that is important for healthy circadian rhythms and good sleep.
This could undoubtedly decrease sleep quality, but it can also cause other serious long-term problems.
It can be bad if you see the light
The new study is based on a study of children and adolescents aged 9 to 1
Although the researchers used fluorescent room lights in their study, the authors point out that smartphone use is now common in children too preschool children, the circadian effects of their use could be considerable because they give children bright light near the face expose.
There are at least three reasons that too much light during the evening could be important for children's health, and all are terrible: depression, suicide and cancer
Excessive evening electric light is part of what I call "light pollution "What is defined as 'pollution of the night by electric light, whether indoors or outdoors in the neighborhood and city.' It is a fast-growing problem in the modern world.
A common reaction to severe depression is suicide. Well over 40,000 Americans die each year from suicide, more than car accidents and close to deaths from colorectal cancer. In addition, nearly half a million are being hospitalized for self-harm, many of whom have been injured in their failed suicide attempt.
This is especially tragic when it happens to very young people.
Jean Twenge studies mental health and social adaptation in young people, especially after 1995. Her research has focused on smartphones, as described in several informative and provocative recent articles by The Conversation. The articles are based on their own studies published in peer-reviewed scientific journals.
Twenge has found connections between "new media" screen time (eg, smartphones) and risk of depression and suicide in adolescents from two large samples of adolescents in the US
Twenge suggests potential causes for their outcomes social isolation, sleep deprivation or both. In another recent analysis, Twenge focused on sleep duration and concluded that "increased short-term sleep times in young adults from the recent increase (from 35 percent to 41 percent and from 37 percent to 43 percent) at the time of the new Could be involved in the media. "  Circadian Disruption could be the underlying culprit. Bright light in the evening delays the transition to nocturnal physiology, which should begin at dusk. This degrades the quality of sleep.
There is also evidence that circadian disorders can lead to depression and other unfavorable mood swings.
Light Pollution and Cancer in Children
In 2012, I was invited to speak at a conference about causes of childhood cancer sponsored by the Foundation Children with Leukemia UK. My job was to discuss possible mechanisms by which excessive nighttime exposure to electrical light could increase a child's cancer risk. I wrote a scientific paper on the topic, which was published shortly before the conference.
This charity has a tragic history of origin. The son of a very wealthy man in the UK, Eddie O & Gorman, died of leukemia in 1987 at the age of 14. His name was Paul. Before his death, Paul asked his parents to help other children with cancer. With the determined support of his sister Jean, his parents Eddie and Marion began fundraising
Jean died of breast cancer at the age of 29, just nine months after Paul's death. Princess Diana heard about the tragedy and offered to charter the charity in 1988. She remained involved in the charity's activities until her own death in 1997.
The charity was renamed Children with Cancer a few years ago  The cause for concern about childhood cancer is the fact that untimely electrical light can disrupt circadian rhythms and that circadian disorders are implicated in adult cancers, although few if any, studies have directly examined cancer in children. The evidence for an effect in children is indirect, but the problem is critical.
Leukemia is the most common childhood cancer. It is a disease of unrestrained growth of white blood cells. These white cells are produced by stem cells that, in normal behavior, produce just enough white cells for a healthy immune system to function as it should. When the stem cells go crazy, leukemia is the result. Recent studies have shown that stem cell proliferation is under circadian control. Therefore, too much light at night could destabilize the growth of stem cells.
Children with Cancer UK will hold its next scientific meeting in Westminster, London in September of this year. I will focus on these new results of evening light-induced melatonin suppression in children for my presentation.
Too much light at night early in life, even in utero
Early life, including in utero, is a particularly vulnerable time. The establishment of circadian rhythms begins early in pregnancy, but is not fully established at birth, as each new parent becomes aware.
For these reasons, the focus of research should be on the effects of untimely electric light on pregnant women, such as changes in hormone production, which could then affect fetal development. Scientists studying this must also focus on developmental effects on young children and adolescents.
For example, it is not known to what extent night-lights in nurseries alter the consolidation of circadian rhythm in infants, and whether infants who suffer at high-lit evenings at home are at risk. I believe that this is an urgent issue as negative effects could lead a child to a lifelong disease and death toll.
Richard G. "Bugs" Stevens, Professor, School of Medicine, University of Connecticut