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Saturday, April 13, 2013

Sunlight & ADHD

Attention Deficit Hyperactivity Disorder, or ADHD, diagnoses are on the rise.  New data from the CDC, or Centers for Disease Control, show that nearly 1 in 5 high school boys in the US, and almost 1 in 10 school age children overall, have been given a medical diagnosis of ADHD.  The diagnosis is twice as common in boys (15%) as in girls (7%), and it rises with age—doubling in both boys and girls from early childhood (ages 4-9) to late teenage (14-17) years.  Rates in Michigan are among the highest in the US.

But rates in the southwest are remarkably low.  A new study shows that states with high solar intensity, like California and Arizona, have much lower rates of ADHD than states with low solar intensity, like Michigan or Ohio.  Sunlight seems to have a protective effect, accounting for as much as 34% to 57% of the variance in ADHD risk.  And the same effect shows up internationally: children in sunny countries, like Mexico and Spain, are at much lower risk than children in cloudy countries, like France or the Netherlands—where the study was done.
Researchers suggest that children in cloudy countries should get out more.  "Exposure to more intense early day natural light, such as might occur by asking them to walk their dog in the morning or to walk or ride their bikes to school instead of being driven, could be beneficial."  It probably wouldn't hurt.