Coronary artery bypass graft surgery and dementia risk in the cardiovascular health study by Kuźma, E, Airdrie, J, Littlejohns, T, Lourida, I, Thompson-Coon, J, Lang, I, Scrobotovici, M, Thacker, E, Fitzpatrick, A, Kuller, L, Lopez, O, Longstreth, W, Ukoumunne, O, Llewellyn, D