1. National Research Council of Italy (CNR‐CSFET), Italian Longitudinal Study on Aging, Florence, Italy;
2. Department of Neurological and Psychiatric Sciences, University of Florence, Florence, Italy;
3. Department of Neurology, University of Bari, Bari, Italy;
4. National Research Council of Italy (CNR), Center on Aging, Padua, Italy;
5. INRCA, Fermo, Italy;
6. Institute of Hygiene, University of Padua, Padua, Italy;
7. Institute of Clinical Neurology, University of Milan, Milan, Italy; and
8. Laboratorio di Epidemiologia e Biostatistica, Istituto Superiore di Sanità, Rome, Italy.