Difference in brain volumes and brain ageing years in WHR groups of different age groups
| Age group, year | N | MRI brain measures* | Mean brain volume, cm3† | Years of brain ageing‡ | |||
| Low level WHR§ | Medium level WHR§ | High level WHR§ | Medium level WHR§ | High level WHR§ | |||
| <60 | 1112 | TCBV | 1051.18 | 1050.42 | 1047.21 | 0.3 | 1.3 |
| GMV | 590.48 | 588.21 | 586.83 | 1.7 | 2.7 | ||
| WMV | 460.70 | 462.22 | 460.38 | −0.9 | 0.2 | ||
| WMHV | 1.39 | 1.73 | 2.11 | 1.1 | 2.4 | ||
| 60–64 | 571 | TCBV | 1030.53 | 1034.42 | 1031.25 | −1.3 | −0.2 |
| GMV | 578.32 | 580.23 | 573.86 | −1.4 | 3.3 | ||
| WMV | 452.21 | 454.19 | 457.39 | −1.2 | −3.1 | ||
| WMHV | 2.10 | 2.58 | 3.51 | 1.6 | 4.8 | ||
| ≥65 | 730 | TCBV | 1007.15 | 1005.05 | 1006.00 | 0.7 | 0.4 |
| GMV | 569.52 | 568.17 | 563.26 | 1.0 | 4.6 | ||
| WMV | 437.63 | 436.88 | 442.74 | 0.4 | −3.0 | ||
| WMHV | 5.37 | 5.93 | 5.53 | 1.9 | 0.5 | ||
| All participants | 2413 | TCBV | 1033.10 | 1032.84 | 1031.45 | 0.1 | 0.5 |
| GMV | 581.36 | 580.21 | 576.40 | 0.8 | 3.7 | ||
| WMV | 451.74 | 452.63 | 455.05 | −0.5 | −2.0 | ||
| WMHV | 2.75 | 3.21 | 3.40 | 1.6 | 2.2 | ||
*Expressed by residual method.
†Adjusted for age, sex, current smoking, current drinking, ethnicity and educational level.
‡Calculation of years of brain ageing is based on regressing each brain volume onto age at MRI, where the slope is the estimate of the change in residual adjusted brain volume per year of age (TCBV=−3.0375×age; GMV=−1.3579×age; WMV=−1.6796×age; WMHV=0.2963×age).
§WHR groups: low level: <0.85 (female), <0.90 (male); medium level: 0.85–1.00 (female), 0.90–1.00 (male); high level: >1.00 (female), >1.00 (male).
GMV, gray matter volume; TCBV, total cerebral brain volume; WHR, waist-hip ratio; WMHV, white matter hyperintensity volume; WMV, white matter volume.