APOE and type 1 diabetes mellitus: Participants lost to follow-up (died or unable to complete any cognitive test; Figure A1) after 5 years (n = 501) had slightly higher median tHcy (P = .01) and plasma vitamin B12 concentrations (P = .05); were more likely to be APOE ε4 carriers (P = .01); were less likely to drink alcohol (P < .001); less physically active (P < .001); more likely to have a history of CVD (P = .003), diabetes type 1 and 2 (P = .01), and Alzheimer disease/dementia (P < .001); and more likely to live in institutions (P < .001) at baseline compared with those who had SMMSE data 5 years later.