Table 1. Characteristics of Participants in the Magnetic Resonance Imaging Substudy.
| Variable | Completed baseline scan | Completed follow-up scan | ||
|---|---|---|---|---|
| Intensive (n = 356) | Standard (n = 317) | Intensive (n = 251) | Standard (n = 203) | |
| Age, mean (SD), y | 67.6 (8.0) | 66.9 (8.5) | 67.7 (7.7) | 66.4 (7.8) |
| Age ≥75 y, No. (%) | 83 (23.3) | 67 (21.1) | 54 (21.5) | 37 (18.2) |
| Montreal Cognitive Assessmenta | 24 (21 to 26) | 24 (22 to 26) | 24 (21 to 27) | 24 (22 to 27) |
| Total brain volume, mean (SD), cm3 | 1127.1 (113.5) | 1141.7 (114.7) | 1108.3 (106.7) | 1124.0 (114.8) |
| WML volume, cm3 | ||||
| No. | 355 | 315 | 249 | 200 |
| Median (IQR) | 3.0 (1.5 to 6.2) | 3.3 (1.6 to 6.1) | 2.9 (1.5 to 5.8) | 3.2 (1.7 to 6.2) |
| Hippocampal volume, cm3 | ||||
| No. | 353 | 316 | 251 | 203 |
| Mean (SD) | 7.4 (0.8) | 7.5 (0.8) | 7.4 (0.8) | 7.5 (0.8) |
| Frontal gray matter volume, cm3 | ||||
| No. | 356 | 317 | 251 | 203 |
| Mean (SD) | 171.0 (20.7) | 173.7 (20.8) | 165.3 (19.1) | 168.9 (20.6) |
| SPARE-ADb | ||||
| No. | 354 | 316 | 255 | 203 |
| Mean (SD) | −1.5 (0.9) | −1.6 (0.9) | −1.2 (1.0) | −1.4 (1.0) |
| Meta-ROI mean cortical thickness, mm | ||||
| No. | 353 | 315 | 252 | 202 |
| Mean (SD) | 2.8 (0.3) | 2.8 (0.3) | 2.6 (0.3) | 2.6 (0.3) |
| Mean FA in the cingulum bundlec | ||||
| No. | 347 | 308 | 252 | 200 |
| Mean (SD) | 0.29 (0.04) | 0.29 (0.03) | 0.29 (0.04) | 0.29 (0.04) |
| Mean FA in the corpus callosum genuc | ||||
| No. | 348 | 309 | 253 | 200 |
| Mean (SD) | 0.41 (0.04) | 0.40 (0.08) | 0.39 (0.08) | 0.38 (0.08) |
| CBF in the posterior cingulate gyrus, mL/100 mg/min | ||||
| No. | 309 | 284 | 174 | 136 |
| Mean (SD) | 62.4 (16.6) | 59.3 (14.3) | 64.0 (15.8) | 59.5 (14.1) |
| rCBF in posterior cingulate gyrus relative to putamen | ||||
| No. | 309 | 284 | 174 | 136 |
| Median (IQR) | 1.3 (1.2 to 1.5) | 1.3 (1.2 to 1.4) | 1.2 (1.1 to 1.4) | 1.2 (1.1 to 1.4) |
| Frontal gray matter CBF, mL/100 mg/min | ||||
| No. | 326 | 296 | 173 | 149 |
| Mean (SD) | 50.1 (14.4) | 48.7 (12.6) | 53.5 (12.5) | 49.0 (12.1) |
Abbreviations: CBF, cerebral blood flow; FA, fractional anisotropy; IQR, interquartile range; rCBF, regional cerebral blood flow; ROI, region of interest; SPARE-AD, spatial pattern for recognition of Alzheimer disease; WML, white matter lesion.
a
Scores range from 0 to 30, with higher scores denoting better cognitive function.
b
Higher positive scores indicate greater similarity to the Alzheimer disease pattern, while lower negative scores indicate greater similarity to a cognitively normal sample.
c
Values range from 0 to 1, with higher values indicating greater limitation of diffusion in a single direction.