Comparison of two modes of vitamin B12 supplementation on neuroconduction and cognitive function among older people living in Santiago, Chile: a cluster randomized controlled trial. a study protocol [ISRCTN 02694183]
Hugo Sánchez*, Cecilia Albala, Lydia Lera, José L Castillo, Renato Verdugo, Manuel Lavados, Eva Hertrampf, Alex Brito, Lindsay Allen and Ricardo Uauy