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. Author manuscript; available in PMC: 2018 Feb 1.
Published in final edited form as: Alzheimers Dement. 2016 Jul 25;13(2):168–177. doi: 10.1016/j.jalz.2016.06.2359

Table 1.

Characteristics of participants and non-participants in imaging studies

MRI
n=672
No MRI
n=398
P value
Age, mean (SD) 79.8 (5.0) 80.6 (5.4) 0.015
Men, n (%) 353 (52.5) 193 (48.5) 0.20
Education, mean (SD) 14.2 (2.9) 13.8 (3.0) 0.032
APOE ε4 carrier, n (%) 156 (23.2) 96 (24.2) 0.70
BMI, mean (SD) 27.4 (4.6) 28.0 (5.7) 0.12
Diabetes, n (%) 99 (14.7) 73 (18.3) 0.12
Hypertension, n (%) 517 (76.9) 328 (82.4) 0.034
Dyslipidemia, n (%) 545 (81.1) 330 (82.9) 0.46
Stroke, n (%) 25 (3.7) 33 (8.3) 0.001
Congestive heart failure, n (%) 42 (6.3) 74 (18.6) <0.001
Coronary artery disease, n (%) 256 (38.1) 181 (45.5) 0.018
Vascular conditions, mean (SD)* 2.9 (1.6) 3.4 (1.7) <0.001
Smoking:
    Never 64 (50.4) 56 (44.4) 0.56
    Former 50 (39.4) 53 (42.1)
    Current 13 (10.2) 30 (11.9)
Depressive symptoms 27 (4.0) 27 (6.8) 0.046
Global z score 0.5 (0.9) 0.3 (0.8) <0.001
MeDi score, median (IQR) 4.0 (3.0 – 5.0) 4.0 (3.0- 5.0) 0.052
FFQ to MRI, median (IQR) months§ 6.2 (3.6 – 12.7) NA
MCI at time of imaging, n (%) 22 (3.3) NA
Imaging measures://
    Parietal cortical thickness, mm 2.03 (1.95, 2.11) NA
    Temporal cortical thickness, mm 2.65 (2.55, 2.74) NA
    Frontal cortical thickness, mm 2.30 (2.22, 2.37) NA
    Occipital cortical thickness, mm 1.75 (1.69, 1.81) NA
    AD signature cortical thickness, mm 2.77 (2.67, 2.85) NA

MeDi, Mediterranean diet total score; MRI, magnetic resonance imaging; BMI, body mass index; FFQ, food frequency; SD, standard deviation; IQR, interquartile range. Data are based on participants with non-missing data only. P-values are based on the chi-square test for categorical variables and Kruskal-Wallis test for continuous variables.

*

Number of vascular conditions (diabetes, hypertension, coronary heart disease, peripheral vascular disease, obesity, congestive heart failure, atrial fibrillation, dyslipidemia, and stroke).

Depressive symptoms were assessed from the Beck Depression Inventory II.

Composite global cognitive score based on memory, executive function, language and visuospatial skills domain z scores.

§

Time between completion of food frequency questionnaire and MRI imaging.

//

Median (25th, 75th percentile)