TABLE 2.
Incidence rates (IR) and hazard ratios (HR) of dementia at z score threshold of −1.5: Atherosclerosis Risk in Communities Neurocognitive Study (ARIC‐NCS), 2011–2020 (N = 5296).
| Unadjusted IR | Adjusted IR | Unadjusted HR | Adjusted HR | ||||
|---|---|---|---|---|---|---|---|
| No. dementia/No. (%) | IR (95% CI) | IR (95% CI) | HR (95% CI) | P | HR (95% CI) | P | |
| Baseline diagnosis | |||||||
| Normal | 587/4317 (13.6%) | 18.20 (16.82–19.69) | 16.29 (15.02–17.66) | 1 [Reference] | <0.0001 | 1 [Reference] | <0.0001 |
| Mild cognitive impairment | 385/979 (39.3%) | 61.26 (55.87–67.17) | 45.47 (40.87–50.58) | 3.65 (3.21, 4.15) | 3.11 (2.73, 3.55) | ||
| Language with or without other domains | |||||||
| Normal | 772/4669 (16.5%) | 22.50 (21.02–24.10) | 18.85 (17.47–20.34) | 1 [Reference] | <0.0001 | 1 [Reference] | <0.0001 |
| Abnormal | 200/627 (31.9%) | 47.27 (41.46–53.88) | 38.71 (33.75–44.40) | 2.18 (1.87, 2.55) | 2.20 (1.88, 2.57) | ||
| Executive function with or without other domains | |||||||
| Normal | 725/4552 (15.9%) | 21.52 (20.05–23.09) | 17.94 (16.59–19.40) | 1 [Reference] | <0.0001 | 1 [Reference] | <0.0001 |
| Abnormal | 247/744 (33.2%) | 50.98 (45.34–57.31) | 43.02 (37.94–48.78) | 2.55 (2.20, 2.94) | 2.69 (2.31, 3.12) | ||
| Memory with or without other domains | |||||||
| Normal | 692/4602 (15.0%) | 20.34 (18.92–21.87) | 17.38 (16.08–18.79) | 1 [Reference] | <0.0001 | 1 [Reference] | <0.0001 |
| Abnormal | 280/694 (40.3%) | 61.97 (55.64–69.03) | 49.11 (43.73–55.14) | 3.25 (2.82, 3.73) | 3.14 (2.73, 3.62) | ||
| Number of abnormal domains | |||||||
| Normal | 487/3740 (13.0%) | 17.37 (15.93–18.93) | 14.72 (13.45–16.12) | 1 [Reference] | <0.0001 | 1 [Reference] | <0.0001 |
| Abnormal domain | 288/1127 (25.6%) | 36.75 (32.93–41.01) | 30.33 (27.01–34.05) | 2.21 (1.91, 2.55) | 2.20 (1.90, 2.55) | ||
| Abnormal domains | 152/349 (43.6%) | 68.84 (59.60–79.52) | 56.48 (48.67–65.54) | 4.32 (3.60, 5.18) | 4.43 (3.69, 5.33) | ||
| Abnormal domains | 45/80 (56.3%) | 100.61 (77.29–130.97) | 80.44 (61.54–105.13) | 6.89 (5.08, 9.36) | 7.29 (5.36, 9.93) | ||
| Specific patterns of abnormal domains | |||||||
| Normal | 487/3740 (13.0%) | 17.37 (15.93–18.93) | 14.77 (13.50–16.17) | 1 [Reference] | <0.0001 | 1 [Reference] | <0.0001 |
| Abnormal language only | 67/316 (21.2%) | 29.51 (23.44–37.14) | 24.31 (19.23–30.73) | 1.73 (1.34, 2.24) | 1.70 (1.31, 2.19) | ||
| Abnormal executive function only | 94/427 (22.0%) | 31.85 (26.26–38.64) | 27.61 (22.81–33.42) | 1.94 (1.55, 2.42) | 2.03 (1.62, 2.55) | ||
| Abnormal memory only | 127/384 (33.1%) | 48.56 (41.26–57.15) | 38.36 (32.44–45.37) | 2.93 (2.41, 3.56) | 2.82 (2.32, 3.44) | ||
| Multidomain, normal memory | 44/119 (37.0%) | 58.47 (44.29–77.20) | 52.49 (39.51–69.72) | 3.63 (2.67, 4.94) | 4.13 (3.03, 5.65) | ||
| Multidomain, abnormal memory | 108/230 (47.0%) | 74.20 (62.75–87.74) | 58.45 (49.34–69.24) | 4.68 (3.80, 5.76) | 4.57 (3.70, 5.64) | ||
| All domains abnormal | 45/80 (56.3%) | 100.61 (77.29–130.97) | 80.65 (61.73–105.36) | 6.89 (5.08, 9.36) | 7.30 (5.36, 9.94) | ||
Note: Dementia diagnosis was determined by adjudicated review of in‐person cognitive examinations, telephone interviews, informant interviews, hospitalization records, and death certificates. Diagnosis date based on the last clinical examination or phone‐based assessment. If dementia was ascertained from a telephone interview, informant interview, hospitalization record, or death certificate, the date was defined as 180 days prior to the documented incident or interview. Incidence rates per 1000 person‐years were calculated from Poisson regression models with robust error variance. Hazard ratios were calculated from cause‐specific, Cox proportional hazards regression models. Adjusted models integrated baseline age, sex, race‐center, and education as time‐invariant covariates.
Abbreviations: CI, confidence intervals; IR, incidence rates per 1000 person‐years.