[1] Indiana Univ, Sch Med, Sect Adolescent Med, Dept Pediat, Indianapolis, IN 46202 USA
[2] Indiana Univ, Sch Med, Sect Child Dev, Dept Pediat, Indianapolis, IN 46202 USA
[3] Indiana Univ, Sch Med, Dept Med, Div Biostat, Indianapolis, IN USA
[4] Indiana Univ, Sch Nursing, Dept Family Hlth, Indianapolis, IN 46204 USA