Table 1. Sample characteristics, mobility measures, and neuroimaging markers for all three groups.
| Young1 (aged < 50) N=51 |
Young-old2 (aged 50-70) N=209 |
Old-old3 (aged 70-96) N=233 |
p-value | Pairwise comparison test |
|
|---|---|---|---|---|---|
| Characteristics | |||||
| Age, years | 42.1±5.4 | 62.1±4.9 | 78.2±5.4 | <.001 | 1<2, 2<3, 1<3 |
| Female | 24 (47.1) | 136 (65.1) | 114 (48.9) | 0.001 | 1<2, 2>3 |
| Education, years | 17±2 | 17±3 | 17±3 | 0.391 | - |
| Black | 10 (19.6) | 63 (30.1) | 45 (19.3) | 0.021 | - |
| Height, m | 1.72±0.10 | 1.68±0.09 | 1.67±0.10 | 0.001 | 1>2, 1>3 |
| Weight, kg | 79.6±18.5 | 78.8±16.4 | 74.3±13.6 | 0.005 | 2>3 |
| Body mass index, kg/m2 | 26.8±6.0 | 27.7±4.8 | 26.6±3.9 | 0.025 | 2<3 |
| Health-related conditions | |||||
| Smoker | 5 (10.2) | 13 (6.3) | 5 (2.2) | 0.020 | 1>3, 2>3 |
| Leg pain when walking | 3 (6.0) | 41 (19.6) | 28 (12.0) | 0.071 | - |
| Difficulty walking ¼ mile | 1 (2.1) | 9 (4.3) | 7 (3.0) | 0.647 | - |
| Osteoarthritis of knees | 1 (2.0) | 59 (28.2) | 71 (30.5) | 0.002 | 1<2 |
| Walking ability score | 8.7±1.2 | 8.3±1.7 | 8.1±1.6 | 0.031 | 1>3 |
| Mobility measures | |||||
| Lap time variation, sec | 0.64±0.26 | 0.71±0.30 | 0.87±0.42 | <.001 | 2<3, 1<3 |
| Mean lap time, sec | 21.8±2.6 | 24.9±3.1 | 28.9±6.0 | <.001 | 1<2, 2<3,1<3 |
| Microstructural white matter integrity: Fractional anisotropy | |||||
| Uncinate fasciculus | 0.3579±0.0407 | 0.3565±0.0402 | 0.3536±0.0431 | 0.692 | - |
| Superior longitudinal fasciculus |
0.4614±0.0206 | 0.4484±0.0238 | 0.4452±0.0337 | 0.001 | 1>2, 1>3 |
| Inferior fronto-occipital fasciculus |
0.3981±0.0249 | 0.3810±0.0242 | 0.3695±0.0299 | <.001 | 1>2, 2>3, 1>3 |
| Genu of corpus callosum | 0.5584±0.0487 | 0.5196±0.0541 | 0.4661±0.0721 | <.001 | 1>2, 2>3, 1>3 |
| Body of corpus callosum | 0.5446±0.0327 | 0.5304±0.0378 | 0.4995±0.0523 | <.001 | 2>3, 1>3 |
| Splenium of corpus callosum |
0.6289±0.0292 | 0.6242±0.0299 | 0.6032±0.0565 | <.001 | 2>3, 1>3 |
| Anterior limb of the internal capsule |
0.5333±0.0302 | 0.5259±0.0363 | 0.5091±0.0514 | <.001 | 2>3, 1>3 |
| Anterior corona radiate | 0.4202±0.0280 | 0.3918±0.0299 | 0.3607±0.0356 | <.001 | 1>2, 2>3, 1>3 |
|
Macrostructural white
matter damage |
0.0004±0.0017 | 0.0012±0.0026 | 0.0040±0.0057 | <.001 | 2<3, 1<3 |
Note: Samples were free of Parkinson’s and stroke and did not use a walking aid for the 400m walk. Values were mean ± SD or N (%) as noted. Macrostructural white matter damage was expressed as a ratio of total volume of white matter hyperintensities to the intracranial volume.