[1] Univ Penn, Sch Med, Dept Neurol, Philadelphia, PA 19104 USA
[2] Univ Penn, Dept Biostat Epidemiol & Informat, Philadelphia, PA 19104 USA
[3] Parkinsons Fdn Women PD Initiat, New York, NY USA
[4] Univ Colorado, Dept Neurol, Denver, CO 80202 USA
[5] Henry Ford Med Grp, Dept Neurosurg, Detroit, MI USA
[6] Greenville Hlth Syst Univ, Med Grp, Greenville, SC USA
[7] Univ Maryland, Sch Med, Dept Neurol, Baltimore, MA USA
[8] Univ Penn, Leonard Davis Inst Hlth Econ, Philadelphia, PA 19104 USA
[9] Univ Penn, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[10] Healthcare Outcomes & Dispar Working Grp, Parkinson Study Grp, Rochester, NY USA