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. 2020 Sep 18;76(9):1627–1632. doi: 10.1093/gerona/glaa238

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.