[1] Brown Univ, Dept Epidemiol, Providence, RI 02912 USA
[2] Brown Univ, Dept Biostat, Providence, RI 02912 USA
[3] Johns Hopkins Univ, Dept Environm Hlth & Engn, Baltimore, MD USA
[4] Univ Cincinnati, Coll Med, Dept Radiol, Cincinnati Childrens Hosp Med Ctr, Cincinnati, OH USA
[5] Univ Cincinnati, Coll Med, Dept Pediat, Cincinnati Childrens Hosp Med Ctr, Cincinnati, OH USA
[6] Univ Penn, Dept Biostat Epidemiol & Informat, Philadelphia, PA 19104 USA
[7] Brown Univ, Dept Family Med, Warren Alpert Med Sch, Providence, RI 02912 USA
[8] Simon Fraser Univ, Fac Hlth Sci, Vancouver, BC, Canada