Table 1.
Baseline characteristics
| Variable | Total sample | Dementia sample | Stroke sample |
|---|---|---|---|
| Number of participants | 3294 | 1834 | 3210 |
| Age, y, mean (SD) | 65 (11) | 72 (8) | 65 (11) |
| Women, n (%) | 1849 (56) | 809 (44) | 1808 (56) |
| Education, n (%) | |||
| No high-school diploma | 239 (7) | 189 (11) | 223 (7) |
| High-school diploma only | 1008 (32) | 637 (36) | 982 (32) |
| Some college | 902 (28) | 484 (27) | 881 (28) |
| College graduate | 1050 (33) | 482 (27) | 1031 (33) |
| CES-D, median (IQR) | 3 (1–7) | 3 (1–6) | 3 (1–7) |
| CES-D ≥16, n (%) | 263 (8) | 134 (7) | 257 (8) |
| BMI, mean (SD), kg/m2 | 28 (5) | 28 (5) | 28 (5) |
| Current smoker, n (%) | 360 (11) | 134 (7) | 353 (11) |
| Physical Activity Index, mean (SD) | 38 (6) | 38 (6) | 38 (6) |
| Prevalent comorbidity, n (%) | |||
| Cardiovascular disease∗ | 569 (17) | 446 (24) | 489 (15) |
| Stroke | 80 (2) | 61 (3) | 3210 (100) |
| Atrial fibrillation | 193 (6) | 153 (8) | 177 (6) |
| Diabetes mellitus | 408 (13) | 275 (17) | 384 (13) |
| Stage 1 or higher JNC-VII hypertension | 1671 (51) | 1143 (62) | 1602 (50) |
| Systolic blood pressure, mean (SD), mm Hg | 129 (20) | 134 (20) | 129 (20) |
| Total cholesterol, mean (SD), mg/dL | 199 (37) | 197 (37) | 199 (37) |
| BDNF by Social Network Index,† median (IQR), pg/mL | |||
| Low | 24,112 (18,926–29,314) | 22,708 (17,342–28,067) | 24,112 (19,045–29,314) |
| Medium | 23,237 (17,807–28,944) | 22,612 (17,579–28,154) | 23,623 (17,887–28,969) |
| Medium-high | 23,804 (18,267–29,287) | 22,961 (17,996–29,122) | 23,789 (18,266–29,286) |
| High | 22,759 (17,647–28,236) | 22,801 (17,767–28,530) | 22,759 (17,675–28,287) |
Abbreviations: BDNF, brain-derived neurotrophic factor; BMI, body mass index; CES-D, Center for Epidemiologic Studies Depression Scale; JNC, Joint National Committee; IQR, interquartile range; SD, standard deviation.
∗
Includes coronary heart disease, congestive heart failure, peripheral vascular disease, ischemic cardiomyopathy, stroke, and transient ischemic attack.
†
Social Network Index score summed to categorize individuals into four levels of social connection based on summed score cutoffs: 0 or 1 being the low socially connected category and 2 (medium), 3 (medium-high), or 4 (high) corresponded to categories of increasing social connectedness.