Table 1.
Characteristics of the Study Cohorts
| CHNS (n = 8119) | CHARLS (n = 9304) | |
|---|---|---|
| Age, y | 49.9 ± 14.1 | 59.3 ± 9.4 |
| Young and middle-aged adults (<60 y) | 5978 (73.6) | 5115 (55.0) |
| Older adults (≥60 y) | 2141 (26.4) | 4189 (45.0) |
| Gender | ||
| Women | 4342 (53.5) | 4972 (53.4) |
| Men | 3777 (46.5) | 4332 (46.7) |
| Education | ||
| No schooling | 1844 (25.8) | 2802 (30.1) |
| Primary school | 1624 (22.7) | 3823 (41.1) |
| Middle school | 2717 (38.0) | 1804 (19.4) |
| High school or more | 971 (13.6) | 875 (9.4) |
| Marital status | ||
| Currently married | 6990 (86.5) | 7763 (83.4) |
| Others | 1096 (13.6) | 1541 (16.6) |
| Smoking status | ||
| Nonsmoker | 5849 (72.1) | 5641 (60.9) |
| Smoker | 2266 (27.9) | 3622 (39.1) |
| Alcohol consumption | ||
| Nondrinker | 5445 (67.1) | 5673 (61.1) |
| Drinker | 2671 (32.9) | 3615 (38.9) |
| BMI categories* | ||
| Underweight | 482 (6.0) | 629 (6.9) |
| Normal | 4281 (53.2) | 4793 (52.3) |
| Overweight | 2482 (30.8) | 2681 (29.2) |
| Obese | 805 (10.0) | 1065 (11.6) |
| Disease counts | ||
| 0 | 6544 (80.6) | 2778 (29.9) |
| 1 | 1245 (15.3) | 2964 (31.9) |
| 2 | 281 (3.5) | 2035 (21.9) |
| 3+ | 47 (0.6) | 1519 (16.3) |
| Healthy† | 3650 (45.3) | 1607 (17.3) |
| Died | 221 (2.7) | 394 (4.2) |
| Biomarkers selected for calculating KDM-BA and PD | ||
| Total cholesterol, mmol/L | 4.9 ± 1.0 | 5.0 ± 1.0 |
| Log(Triglyceride), mmol/L | 0.3 ± 0.6 | 0.2 ± 0.5 |
| Glycated hemoglobin, % | 5.6 ± 0.9 | 5.3 ± 0.8 |
| Urea, mmol/L | 5.5 ± 1.5 | 5.6 ± 1.6 |
| Creatinine, µmol/L | 86.9 ± 17.1 | 68.9 ± 16.5 |
| Albumin, g/L | 47.5 ± 3.4 | — |
| Log(high-sensitivity C-reactive protein), mg/L | −0.07 ± 1.5 | 0.2 ± 1.1 |
| Red blood cell count, 1012 cells/L | 4.7 ± 0.7 | — |
| Platelet count, 109 cells/L | 213.2 ± 67.3 | 212.0 ± 72.8 |
| Log(Ferritin), ng/mL | 4.3 ± 1.2 | — |
| Transferrin, mg/dL | 288.3 ± 55.6 | — |
| Systolic blood pressure, mmHg | 124.5 ± 18.8 | 130.9 ± 21.6 |
Notes: BMI = body mass index; CHARLS = China Health and Retirement Longitudinal Study; CHNS = China Health and Nutrition Survey; KDM-BA = Klemera and Doubal method-biological age; PD = physiological dysregulation; SD = standard deviation. Values are presented as mean ± SD or No. (%). Percentages may not sum to 100 because of rounding. There were missing data on ethnicity (n = 27), education (n = 963), marital status (n = 33), smoking status (n = 4), alcohol consumption (n = 3), BMI categories (n = 69), and disease (n = 2) in CHNS. There were missing data on smoking status (n = 41), alcohol consumption (n = 16), BMI categories (n = 136), and disease (n = 8) in CHARLS.
*BMI was calculated as weight in kilograms divided by height in meters squared. Underweight was defined as BMI < 18.5 kg/m2; normal was defined as 18.5 ≤ BMI < 24.0 kg/m2; overweight was defined as 24.0 ≤ BMI < 28.0 kg/m2; and obese was defined as BMI ≥ 28 kg/m2.
†Healthy participants were defined as those having no disease and normal BMI.