Table 1.
Descriptive statistics of the overall study population
| Predictors and covariates | Value | Standard deviation | Range |
|---|---|---|---|
| Sociodemographic characteristics (N = 8806) | |||
| Age (years), mean | 68.9 | 8.96 | 57–107 |
| Female, % | 54 | 0–1 | |
| Race/ethnicity, % | |||
| Non-Hispanic White | 78 | 0–1 | |
| Non-Hispanic Black | 10 | 0–1 | |
| Hispanic/Latino | 9 | 0–1 | |
| Other race | 3 | 0–1 | |
| Education (years), mean | 13.2 | 2.92 | 0–17 |
| Married, % | 59 | 0–1 | |
| Self-reported mobility limitation (N = 8806), % | |||
| Difficulty walking several blocks | 31 | 0–1 | |
| Difficulty walking one block | 15 | 0–1 | |
| Difficulty climbing several flights of stairs | 46 | 0–1 | |
| Difficulty climbing one flight of stairs | 19 | 0–1 | |
| Mobility Limitation Index, mean | 1.11 | 0–4 | |
| CKD biomarkers (N = 8806) | |||
| Serum creatinine (mg/dL), mean | 0.96 | 0.46 | 0.28–14.1 |
| eGFR (mL/min/1.73 m2), mean | 75.5 | 22.33 | 2.69–140.25 |
| CKD Stages 3b–5 (eGFR ≤45 mL/min/1.73 m2), % | 10 | 0–1 | |
| CKD Stages 3–5 (eGFR ≤60 mL/min/1.73 m2), % | 29 | 0–1 | |
| Self-reported health conditions (N = 8806), % | |||
| Hypertension | 59 | 0–1 | |
| Diabetes | 25 | 0–1 | |
| Heart condition | 25 | 0–1 | |
| Stroke | 7 | 0–1 | |
| Trouble with pain | 40 | 0–1 | |
| BMI (N = 8683), mean | 28.51 | 6.01 | 10.30–70.69 |
| Obese (BMI >30 kg/m2), % | 33 | 0–1 | |
| Social contact and participation* (N = 3420), mean | |||
| Frequency of contact with family and friends | 3.68 | 1.07 | 1–6 |
| Adult children | 3.84 | 1.42 | 1–6 |
| Extended family | 3.19 | 1.47 | 1–6 |
| Friends | 4.07 | 1.30 | 1–6 |
| Participation in social activities | 6.41 | 4.95 | 0–31 |
| Taking care of grandchildren | 2.08 | 1.88 | 0–6 |
| Volunteering for youth organizations | 0.59 | 1.14 | 0–6 |
| Charity work | 1.10 | 1.51 | 0–6 |
| Educational activities | 0.62 | 1.14 | 0–6 |
| Social clubs | 1.35 | 1.61 | 0–6 |
| Civic organizations | 0.71 | 1.09 | 0–6 |
*
Significant differences (P < 0.05) between the full and half-sample include race/ethnicity (e.g. White: 78% versus 82%); no other variables are significantly different among the two samples.