Study Population
This study involved analyses of cross-sectional data from US
children aged 2 to 18 years (n¼17,344) and adults aged !19
years (n¼24,807) participating in the 2001-2002, 2003-2004,
2005-2006, 2007-2008, and 2009-2010 NHANES. The data
from these five cycles were merged to increase sample size