White light found to supress production of Melatonin - sleep regulating hormone - street lighting and light pollution implications

LED white lights were found to be five times and Metal halide lights three times more powerful in suppressing melatonin production than High Pressure Sodium light

http://www.eurekalert.org/pub_releases/2011-09/uoh-doe091111.php

 

Sleep deprivation in obese teens linked with increased risk of developing type II diabetes

http://www.sciencedaily.com/releases/2008/01/080101093903.htm