A new scientific study shows how preschoolers exposed to intense electric light at night suppress their production of melatonin almost completely. This study is an important step on research in this area, since the suppression of melatonin marks the alteration of our circadian rhythms.
Ten children aged 3 to 5 years were exposed to intense light (~ 1000 lux of a light box) for an hour before their usual bedtime, around 8 in the afternoon. Melatonin suppression (when the body stops producing this hormone) began at 10 minutes and still did not occur for another hour after turning off the light at 9, well into the sleep period. Melatonin is a very important hormone to have healthy circadian rhythms and to sleep well.
This is something that certainly reduces the quality of sleep, but that could also cause other serious long-term problems.
When seeing the light can bad
This new study was based on a 2015 study conducted on children and adolescents aged 9 to 16 years in which it was shown that younger children were more sensitive to exposure compared to older ones. This study used several different levels of light at night in a laboratory environment that oscillated between a dim light (~ 15 lux), moderate (~ 150 lux; similar to a 60W incandescent lamp) or intense (~ 500 lux), measuring body responses to each dose; dim light suppressed melatonin by 9 percent; moderate light about 26 percent; and intense light around 37 percent in younger children, being less in older children.
Although the researchers used fluorescent lamps in their study, the authors suggest that the use of smartphones is common among children today, even among preschoolers, and that the circadian effects of its use could be considerable because phones expose children to intense light near the face.
There are at least three reasons why too much light during the night could affect the health of children and they are all terrible: depression, suicide and cancer.Too much artificial light before going to sleep is part of what I call "Light pollution", something that is defined as "pollution during the night by electric light, either inside or outside the neighborhood and the city." It is a problem that is growing at a dizzying pace in the modern world.
Light pollution in the greatest privacy: the smartphone
Research suggests that smartphone light can disturb circadian rhythms.A common reaction in cases of severe depression is suicide. More than 40,000 Americans die each year from suicide, being a cause of death greater than that of car accidents and close to the number of deaths from colon cancer. In addition, almost half a million people have to be hospitalized for self-harm, many of which are caused by suicide attempts. It is especially tragic when it occurs among the youngest.
Jean Twenge is dedicated to the study of mental health and social adaptation in adolescents, particularly those born after 1995. His research has focused on smartphones, as described by several informative and provocative articles recently published in The Conversation . These articles are based on their own studies published in scientific journals backed by experts.
Twenge has realized that there is a relationship between time before "new media" screens (such as smartphones) and between the risk of depression and suicide in adolescents based on two large studies of young people in the United States.
Twenge proposes as possible causes of its conclusions social isolation, lack of sleep or a combination of both. In another recent analysis, Twenge focused on the amount of sleep and concluded that "the increase in screen time of new media may be involved in recent increases (from 35 percent to 41 percent and 37 percent to 43 percent) of teenagers who don't get enough sleep. "
The interruption of circadian cycles could be the underlying cause. Exposure to intense light at night delays the transition to nocturnal physiology, which should begin at dusk. So it makes the quality of sleep degrade.
There is also evidence that the alteration of circadian cycles can cause depression and other adverse mood swings.
Light pollution and cancer in children
In 2012 I was invited to speak at a conference on causes of childhood cancer sponsored by the Children with Leukemia UK charity. In my talk I explained the possible mechanisms by which excessive exposure to electric light at night could increase the risk of cancer in childrenYes, since I had written a scientific article on the subject published just before the conference.
The history of this charity has a tragic origin: The son of a very rich man in Britain, Eddie O'Gorman, died of leukemia in 1987 at the age of 14. His name was Paul and before his death he asked his parents to help other children with cancer. With the help of his sister Jean, his parents, Eddie and Marion, began raising funds.
His sister Jean died of breast cancer at age 29, just nine months after Paul's death. Princess Diana learned of the tragedy and offered to found the charity in 1988, remaining involved with the activities of the organization until her own death in 1997.
They changed the name a few years ago to Children with Cancer UK.
The basis of concern about the risk of cancer in children is the fact that exposure to light when it is not normal can alter the rhythm of circadian cycles, something that has been linked to cases of cancer in adults. It is true that there are few studies that have examined its consequences in children, so the tests are indirect, although the problem is critical.
Leukemia is the most common childhood cancer. It is a disease that causes uncontrolled growth of white blood cells in the blood. These white blood cells are generated by stem cells and under normal conditions a sufficient amount of white blood cells is produced for the immune system to function healthily. However, when stem cells fail and produce too many white blood cells, the result is leukemia. Recent studies have shown that stem cell proliferation is regulated in part by circadian cycles. Therefore, an excess of light at night could destabilize the growth of stem cells.
Children with Cancer UK will host their next scientific conference in Westminster, London, in September of this year and I will come to present these new results on the suppression of night light-induced melatonin in children.
Too much light at night in the early years, even before birth
The first months, including time in the womb, are a particularly vulnerable period. The establishment of circadian rhythms begins in the first months of gestation, although they are not fully established at birth, something that any new parent realizes.
That is why research attention should be directed to the effects of artificial lighting at night in pregnant women, such as alterations in the production of hormones that could affect the development of the fetus. Scientists in this field should also focus on the effects it has on the development of young children and adolescents.
For example, it is unknown to what extent the lights at night in the baby's room alter the consolidation of the circadian rhythm in the little ones or if those who are exposed to nights with a lot of lighting in the home are at risk. I think this is an urgent issue because adverse effects could influence the child's health for life and even cause premature death.
Author: Richard G. "Bugs" Stevens. Professor at the University of Medicine at the University of Connecticut. Dr. Stevens has been working for a long time trying to help discover why people get cancer. * * This article has been originally published in The Conversation. You can read the original article here. * * Translated by Silvestre Urbón.
