[1] SLIPPERY ROCK UNIV, COLL HLTH & HUMAN SERV, DEPT ALLIED HLTH, SLIPPERY ROCK, PA 16057 USA
[2] UNIV PITTSBURGH, GRAD SCH PUBL HLTH, DEPT EPIDEMIOL, PITTSBURGH, PA 15261 USA
[3] CHILDRENS HOSP PITTSBURGH, DEPT ENDOCRINOL, PITTSBURGH, PA 15261 USA
[4] CHILDRENS HOSP PITTSBURGH, DIV NEPHROL, PITTSBURGH, PA 15261 USA
[5] UNIV PITTSBURGH, MONTEFIORE HOSP, PITTSBURGH, PA 15213 USA