[1] Yale Sch Med, Internal Med & Pediat, New Haven, CT USA
[2] Yale Sch Med, Yale Adult Cyst Fibrosis Program, Sect Pulm Crit Care & Sleep Med, New Haven, CT USA
[3] Univ Michigan Hlth, Mott Childrens Hosp, Dept Pediat, Div Pediat Psychol, Ann Arbor, MI USA
[4] Univ Michigan Hlth, Mott Childrens Hosp, Dept Pediat, Div Pediat Pulmonol, 1500 E Med Ctr Dr, Ann Arbor, MI 48109 USA