[1] Natl Inst Deafness & Other Commun Disorders NIDCD, Epidemiol & Stat Program, NIH, Bethesda, MD 20892 USA
[2] Univ Minnesota, Dept Otolaryngol, Minneapolis, MN USA
[3] Univ Minnesota, Div Epidemiol, Minneapolis, MN 55455 USA
[4] Univ Pittsburgh, Childrens Hosp, Sch Med, Div Pediat Otolaryngol, Pittsburgh, PA 15260 USA
[5] Univ Copenhagen, Rigshosp, Dept Otorhinolaryngol Head & Neck Surg, DK-1168 Copenhagen, Denmark
[6] Norwegian Inst Publ Hlth, Div Mental Hlth, Oslo, Norway
[7] Univ Oslo, Dept Hlth Management & Hlth Econ, Inst Hlth & Soc, Fac Med, Oslo, Norway
[8] Oslo Univ Hosp, Dept Res Innovat & Educ, Oslo, Norway
[9] Childrens Hosp, Pediat Phys Org Childrens, Div Gen Pediat, Boston, MA 02115 USA