1. Division of Health and Nutrition Examination Surveys, National Center for Health Statistics, CDC, Hyattsville, MD, USA
2. Epidemic Intelligence Service, CDC, Atlanta, GA, USA
3. Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Rockville, MD, USA
4. United States Public Health Service, Rockville, MD, USA