[1] Univ Calif Davis, Dept Neurol, Sacramento, CA 95817 USA
[2] Univ Calif Davis, Ctr Neurosci, Sacramento, CA 95817 USA
[3] Boston Univ, Sch Med, Dept Neurol, Boston, MA 02118 USA
[4] Framingham Heart Dis Epidemiol Study, Framingham, MA USA
[5] Boston Univ, Sch Publ Hlth, Dept Biostat, Boston, MA USA
[6] Univ Versailles St Quentin En Yvelines, Dept Epidemiol, Versailles, France