Kilpatrick L, Houston DK, Wilson VK, Lovato J, Ayonayon HN, Cauley JA, Harris T, Simonsick EM, Yaffe K, Kritchevsky SB, Sink KM. Low 25-Hydroxyvitamin D Concentrations and Risk of Incident Cognitive Impairment in Black and White Older Adults: The Health ABC Study. J Nutr Gerontol Geriatr. 2018 Jan-Mar; 37(1):1-13.