Table 2.
Baseline Characteristics of the Overall Study Sample and the Three Activity-Restriction Groups
| Variable | Overall | No Activity Restriction | Moderate Activity Restriction | Severe Activity Restriction | P-Value |
|---|---|---|---|---|---|
| Age, mean ± SD | 75.8 ± 7.2 | 73.4 ± 6.5 | 75.7 ± 6.9 | 80.4 ± 7.6 | <.001 |
| Male, % | 30.9 | 41.3 | 28.2 | 24.0 | .002 |
| Body mass index, kg/m2, mean ± SD | 27.16 ± 4.18 | 27.22 ± 3.99 | 27.75 ± 4.12 | 28.12 ± 4.76 | .04 |
| Number of activity of daily living difficulties, mean ± SD | 0.2 ± 0.6 | 0.2 ± 0.7 | 0.1 ± 0.6 | 0.2 ± 0.7 | .22 |
| Number of instrumental activity of daily living difficulties, mean ± SD | 0.9 ± 1.7 | 0.5 ± 1.6 | 0.7 ± 1.5 | 2.3 ± 2.1 | <.001 |
| Short Performance Physical Battery score, mean ± SD | 9.5 ± 3.0 | 10.5 ± 2.6 | 9.7 ± 2.7 | 6.4 ± 3.4 | <.001 |
| Mini-Mental State Examination score, mean ± SD | 24.6 ± 3.4 | 25.6 ± 3.3 | 24.7 ± 3.2 | 22.7 ± 3.5 | .001 |
| Comorbidity index, mean ± SD | 2.3 ± 1.3 | 2.2 ± 1.3 | 2.3 ± 1.3 | 2.6 ± 1.3 | .07 |
| Smoking, pack-years, mean ± SD | 10.5 ± 20.1 | 13.3 ± 22.1 | 10.3 ± 19.9 | 6.6 ± 15.8 | .72* |
| Center for Epidemiologic Studies Depression Scale score, mean ± SD | 14.6 ± 8.9 | 11.5 ± 7.4 | 14.6 ± 8.7 | 20.1 ± 9.6 | <.001* |
| Walking speed, m/s, mean ± SD | 1.05 ± 0.30 | 1.18 ± 0.27 | 1.06 ± 0.26 | 0.79 ± 0.30 | <.001* |
| Inability to climb a flight of stairs without support, % | 64.9 | 48.3 | 64.6 | 95.0 | <.001 |
| Difficulty walking 400 m, % | 27.3 | 21.3 | 20.6 | 55.2 | <.001 |
Note: The analysis for the trend was adjusted for age and sex.
Age-significant covariate.
SD = standard deviation.