Table 1.
Characteristics of participants according to tertiles of average daily minutes in light physical activity (n=1,059).
| Characteristics | Tertiles of daily light physical activity | ||
|---|---|---|---|
| Low (≤243 minutes) |
Medium (244 – 305 minutes) |
High (>305 minutes) |
|
| Sociodemographics | |||
| Mean (SD) age in years | 69.3 (9.3) | 64.8 (8.4) | 63.7 (8.2) |
| Women (%) | 45.9 | 54.6 | 63.0 |
| Race/ethnicity (%) | |||
| Non-Hispanic White | 83.4 | 82.0 | 77.1 |
| Non-Hispanic Black | 14.0 | 15.8 | 20.3 |
| Other race/ethnicity | 2.6 | 2.2 | 2.6 |
| Education (%)¶ | |||
| High school or less | 13.6 | 13.9 | 15.2 |
| Some or college graduate | 43.5 | 41.7 | 48.0 |
| At least some graduate school | 42.9 | 44.4 | 36.8 |
| Income (%)¶ | |||
| <$25,000 | 12.4 | 10.8 | 10.1 |
| $25,000 - $50,000 | 25.4 | 18.6 | 28.5 |
| >$50,000 | 62.1 | 70.6 | 61.5 |
| Clinical characteristics | |||
| Knee injury (%) | 5.7 | 4.7 | 4.0 |
| Knee surgery (%) | 4.9 | 2.5 | 3.4 |
| Kellgren-Lawrence grade (%) | |||
| 2 | 47.9 | 57.1 | 50.7 |
| 3 | 32.7 | 30.2 | 37.0 |
| 4 | 19.5 | 12.7 | 12.3 |
| Multi-joint symptoms (%) | 45.3 | 46.5 | 51.9 |
| General health | |||
| Body mass index (%)¶ | |||
| Normal | 19.5 | 20.6 | 20.6 |
| Overweight | 35.5 | 42.6 | 39.8 |
| Obese | 45.0 | 36.8 | 39.5 |
| PCS, mean (SD)*¶ | 46.6 (9.7) | 48.3 (8.7) | 48.4 (8.3) |
| MCS, mean (SD)*¶ | 54.5 (8.2) | 55.2 (7.9) | 53.6 (8.5) |
| Charlson Comorbidity Index¶ | |||
| 0 | 62.8 | 73.2 | 70.7 |
| 1 | 18.0 | 16.1 | 19.3 |
| ≥2 | 19.2 | 10.7 | 10.1 |
| CES-D (>16) (%)**¶ | 8.7 | 8.4 | 10.7 |
| Smoking¶ | |||
| Current | 3.8 | 3.7 | 4.6 |
| Past | 39.7 | 38.4 | 38.3 |
| Never | 56.5 | 58.0 | 57.1 |
| At-risk alcohol use (%)¶ | 6.9 | 7.3 | 9.5 |
*
PCS: SF-12 Physical Component Summary scores; MCS: Mental Component Summary scores.
**
CES-D: Centers for Epidemiologic Studies Depression Scale;
¶
Number of participants with missing information: education (6), annual household income (5), body mass index (2), SF-12 Physical Component Summary Scores (11), SF-12 Mental Component Summary Scores (11), Charlson Comorbidity Index (12), elevated depressive symptoms (12), smoking status (15), at-risk alcohol use (8). We imputed missing annual income with conditional means of income given age, sex, race/ethnicity, and education for 79 participants.