1. Department of Preventive Medicine and Childhood Obesity Research Center, University of Southern California; Los Angeles California USA
2. Division of Cancer Prevention; National Cancer Institute; Bethesda Maryland USA
3. Department of Nutritional Sciences, University of Texas at Austin; Austin Texas USA
4. Department of Pediatrics; University of Southern California; Los Angeles California USA
5. Center for Economic and Social Research, University of Southern California; Los Angeles California USA