Sunny climates may reduce ADHD prevalence

A study shows that the prevalence of ADHD may be influenced by sunny climates and amount of sunlight.

Attention-deficit/hyperactivity disorder, or ADHD, is the most common childhood psychiatric disorder. Scientists do not know what causes it, but genetics play a clear role. Other risk factors have also been identified, including premature birth, low birth weight, a mother’s use of alcohol or tobacco during pregnancy, and environmental exposures to toxins like lead.

ADHD is characterized by an inability to focus, poor attention, hyperactivity, and impulsive behavior, and the normal process of brain maturation is delayed in children with ADHD. Many individuals with ADHD also report sleep-related difficulties and disorders. In fact, sleep disorder treatments and chronobiological interventions intended to restore normal circadian rhythms, including light exposure therapy, have been shown to improve ADHD symptoms.

Estimates suggest that the average worldwide prevalence of ADHD ranges from about 5 to 7%, but it also varies greatly by region. A simple visual comparison of data maps released by the U.S. Centers for Disease Control and Prevention and the U.S. Department of Energy that display ADHD prevalence rates by state and solar intensities (sunlight) across the country, respectively, reveals an interesting pattern indicative of an association. So does this mean that there could be an identifiable relationship between ADHD prevalence rates and the sunlight intensity levels of particular regions?

The accumulation of these points led Dr. Martijn Arns and his colleagues to systematically and scientifically investigate this question. They collected and analyzed multiple data-sets from the United States and 9 other countries. Reporting their findings in the current issue of Biological Psychiatry, they did find a relationship between solar intensity and ADHD prevalence.

Even after controlling for factors that are known to be associated with ADHD, both U.S. and non-U.S. regions with high sunlight intensity have a lower prevalence of ADHD, suggesting that high sunlight intensity may exert a ‘protective’ effect for ADHD.

To further validate their work, they also looked at this same relationship with autism and major depressive disorder diagnoses. They found that the findings were specific to ADHD, with no associations observed between the other two disorders.

“The reported association is intriguing, but it raises many questions that have no answers,” commented Dr. John Krystal, Editor of Biological Psychiatry. “Do sunny climates reduce the severity or prevalence of ADHD and if so, how? Do people prone to develop ADHD tend to move away from sunny climates and if so, why?”

As with all scientific research, further work is necessary, including a prospective replication of these findings. It is also important to realize that this data reflects only an association – not a causation – between ADHD and solar intensity levels so worried parents should not start planning cross-country moves.

However, these findings do have significant implications, explains Dr. Arns. “From the public health perspective, manufacturers of tablets, smartphones and PCs could investigate the possibility of time-modulated color-adjustment of screens, to prevent unwanted exposure to blue light in the evening.”

“These results could also point the way to prevention of a sub-group of ADHD, by increasing the exposure to natural light during the day in countries and states with low solar intensity. For example, skylight systems in classrooms and scheduling playtime in line with the biological clock could be explored further.”

Read more here

Sleep disorders, vitamin D and skin pigmentation

This article discusses the link between vitamin D deficiency and the increase of the occurrence of sleep disorders.

Vitamin D Deficiency and Daytime Sleepiness: Skin Pigmentation Is a Complicated Factor

Posted: 01/30/2013 12:11 pm

Vitamin D has received a great deal of attention recently. Vitamin D has long been recognized as primarily a regulator of calcium and phosphorus, helping to protect bone density. In recent years, however, our understanding of the functions of vitamin D in the body has expanded. Vitamin D is now understood to play an important role in metabolic and immune system functions. Vitamin D deficiency has been linked to a number of illnesses and chronic conditions, including high blood pressure, diabetes, metabolic syndrome, pulmonary disease, and chronic pain.

We've seen evidence that vitamin D deficiency is associated with sleep problems, particularly with daytime sleepiness. A new study examined the link between daytime sleepiness and vitamin D, and also considered one of the major risk factors of vitamin D deficiency: skin pigmentation.

Researchers at Louisiana State University investigated the relationship between vitamin D and daytime sleepiness with two specific goals in mind. First, they wanted to determine whether a correlation exists between vitamin D levels in the body and excessive daytime sleepiness. Second, they sought to evaluate the role that race might play in the relationship between daytime sleepiness and vitamin D.

In earlier work, researchers at LSU had observed that more than half of the patients who came to their sleep clinic with sleep problems and with chronic pain were also deficient in vitamin D. They noticed this cluster of symptoms appeared to occur more often in patients who were African-American.

Vitamin D is actually a fat-soluble hormone that the body can receive in food and also through supplements. But the primary -- and most effective -- way the body accumulates vitamin D is during exposure to sunlight. Exposure to sunlight prompts our skin to self-manufacture vitamin D. Increased skin pigmentation lowers the rate of manufacture of vitamin D. Therefore, greater levels of skin pigmentation are considered a risk factor for vitamin D deficiency.

...

The results of the study support a strong correlation between excessive daytime sleepiness and vitamin D. They also indicate that race is a factor in the relationship between vitamin D and daytime sleepiness. But the results were in some ways surprising and indicate a complicated relationship, particularly where race is concerned.

Here's an overview of the most important findings:

• Sixty-five percent of the study population was found to have a vitamin D deficiency.
• The patients with greater skin pigmentation had higher average levels of daytime sleepiness and lower average levels of vitamin D, compared to those with less skin pigmentation
• African-American patients made up 35 percent of the study population, but 55 percent of the group that was deficient in vitamin D
• Only 6 percent of the group without a vitamin D deficiency were African-American
• Among those with deficiencies of vitamin D -- under 20 mg/mL as measured by a blood test -- there was no correlation between vitamin D levels and daytime sleepiness. This is the opposite of what was expected based on prior research.
• An exception to this was found among African-American patients in the study group. Among those African-American patients with vitamin D deficiency, there was a direct correlation between levels of vitamin D and daytime sleepiness. Among these patients, higher vitamin D levels were associated with higher levels of daytime sleepiness -- the exact opposite of what was expected.

It is this last finding that is unexpected, and surprised researchers themselves, who expected to see lower levels of vitamin D associated with higher levels of daytime sleepiness.

Why might this have been the case?    Full article HERE

Sweet Dreams,
Michael J. Breus, PhD 
The Sleep Doctor™ 
www.thesleepdoctor.com

The Sleep Doctor's Diet Plan: Lose Weight Through Better Sleep

Everything you do, you do better with a good night's sleep™ 
Twitter: @thesleepdoctor 
Facebook: www.facebook.com/thesleepdoctor

For more by Dr. Michael J. Breus, click here.

For more on sleep, click here.

Follow Dr. Michael J. Breus on Twitter: www.twitter.com/thesleepdoctor

Study: Sunny climates may reduce ADHD

A study indicates many risk factors for ADHD, and interestingly notes that sunny and warm climates may reduce the condition.

Attention-deficit/hyperactivity disorder, or ADHD, is the most common childhood psychiatric disorder. Scientists do not know what causes it, but genetics play a clear role. Other risk factors have also been identified, including premature birth, low birth weight, a mother's use of alcohol or tobacco during pregnancy, and environmental exposures to toxins like lead.

ADHD is characterized by an inability to focus, poor attention, hyperactivity, and impulsive behavior, and the normal process of brain maturation is delayed in children with ADHD. Many individuals with ADHD also report sleep-related difficulties and disorders. In fact, sleep disorder treatments and chronobiological interventions intended to restore normal circadian rhythms, including light exposure therapy, have been shown to improve ADHD symptoms.

Estimates suggest that the average worldwide prevalence of ADHD ranges from about 5 to 7%, but it also varies greatly by region. A simple visual comparison of data maps released by the U.S. Centers for Disease Control and Prevention and the U.S. Department of Energy that display ADHD prevalence rates by state and solar intensities (sunlight) across the country, respectively, reveals an interesting pattern indicative of an association. So does this mean that there could be an identifiable relationship between ADHD prevalence rates and the sunlight intensity levels of particular regions?

The accumulation of these points led Dr. Martijn Arns and his colleagues to systematically and scientifically investigate this question. They collected and analyzed multiple data-sets from the United States and 9 other countries. Reporting their findings in the current issue of Biological Psychiatry, they did find a relationship between solar intensity and ADHD prevalence.

Even after controlling for factors that are known to be associated with ADHD, both U.S. and non-U.S. regions with high sunlight intensity have a lower prevalence of ADHD, suggesting that high sunlight intensity may exert a 'protective' effect for ADHD.

To further validate their work, they also looked at this same relationship with autism and major depressive disorder diagnoses. They found that the findings were specific to ADHD, with no associations observed between the other two disorders.

"The reported association is intriguing, but it raises many questions that have no answers," commented Dr. John Krystal, Editor of Biological Psychiatry. "Do sunny climates reduce the severity or prevalence of ADHD and if so, how? Do people prone to develop ADHD tend to move away from sunny climates and if so, why?"

As with all scientific research, further work is necessary, including a prospective replication of these findings. It is also important to realize that this data reflects only an association -- not a causation -- between ADHD and solar intensity levels so worried parents should not start planning cross-country moves.

However, these findings do have significant implications, explains Dr. Arns. "From the public health perspective, manufacturers of tablets, smartphones and PCs could investigate the possibility of time-modulated color-adjustment of screens, to prevent unwanted exposure to blue light in the evening."

"These results could also point the way to prevention of a sub-group of ADHD, by increasing the exposure to natural light during the day in countries and states with low solar intensity. For example, skylight systems in classrooms and scheduling playtime in line with the biological clock could be explored further."

Read more here

Camping helps you feel more rested

A study claims a week of camping giving a break from artificial light helps you feel more rested.

Getting away from it all really does make you feel well-rested.

A new study published in Current Biology says camping for a week can help improve sleep by resetting the body’s natural clock.

Researchers at the University of Colorado Boulder found that spending time in the great outdoors —
and away from alarm clocks, electric lights and other modern distractions — can sync up sleep patterns to the sunrise and sunset. That’s the sleep schedule humans are meant to have, scientists say.

The study found that when artificial light is available, people tend to stay up much later than they should.

“What’s remarkable is how, when we’re exposed to natural sunlight, our clocks perfectly become in synch in less than a week to the solar day,” professor Kenneth Wright, who led the study, said in a report on the university’s website.

“Some people are morning types and others like to stay up later. What we found is that natural light-dark cycles provide a strong signal that reduces the differences that we see among people—night owls and early birds—dramatically,” Wright added.

For those who can’t take a week off to go camping, similar benefits can be achieved by turning off the lights earlier at night, dimming computer screens and by beginning the day with a walk outside.

Read more here