Table 1.
Descriptive statistics
| e4 absent (N = 6040; 74%) | e4 present (N = 2147; 26%) | Effect size | P value | |
|---|---|---|---|---|
| Demographic/lifestyle variables | ||||
| Age in years, mean (SD) | 61.66 (7.03) | 61.19 (7.04) | 0.07 | 0.009 |
| Gender, male N (%) | 2916 (48.28) | 941 (43.83) | 0.04 | <0.001 |
| Townsend score, mean (SD) | −2.035 (2.58) | −1.98 (2.58) | 0.02 | 0.367 |
| Smoking history, ever N (%) | 2249 (40.32) | 848 (39.55) | 0.07 | 0.536 |
| Brain MRI values | ||||
| Left hippocampal volume (mm3) | 3821.69 (468.75) | 3814.99 (446.79) | 0.01 | 0.613 |
| Right hippocampal volume (mm3) | 3933.61 (480.72) | 3924.82 (478.75) | 0.02 | 0.521 |
| Normalised total grey matter (mm3) | 796,681.00 (47,417.56) | 800,931.70 (46,699.26) | 0.09 | 0.002 |
| Normalised total white matter (mm3) | 711,833.90 (40,033.25) | 713,252.30 (41,790.69) | 0.04 | 0.220 |
| White matter hyperintensity vol. (mm3) [before log-transform] | 3517.85 (4480.04) | 3710.22 (4657.41) | 0.04 | 0.157 |
| Disease prevalence rates | ||||
| Coronary heart disease N, % | 194 (3.22) | 59 (2.75) | 0.01 | 0.287 |
| Hypertension N, % | 1387 (22.99) | 492 (22.95) | <0.01 | 0.971 |
| Diabetes N, % | 298 (4.97) | 85 (4.00) | 0.02 | 0.067 |
Effect size = Cohen’s d for continuous data; Cramer’s V for frequency data