Table 1 Baseline characteristics of study participants used for the gene-specific screening for CpG sites, differentially methylated according to urinary 8-isoprostane levels
Characteristics | Derivation set (n = 1000) | 1st validation set (n = 548) | 2nd validation set (n = 741) | P value# |
|---|---|---|---|---|
Age (year, median, IQR) | 62 (57–67) | 62 (57–67) | 62 (56–67) | 0.30 |
Sex (n, %) | < 0.001 | |||
Female | 500 (50.0) | 324 (61.0) | 415 (56.0) | |
Male | 500 (50.0) | 224 (39.0) | 326 (44.0) | |
Education (n, %) | 0.95 | |||
< 9 years | 737 (73.7) | 411 (75.0) | 548 (74.0) | |
9–11 years | 155 (15.5) | 85 (15.5) | 115 (15.5) | |
> 12 years | 108 (10.8) | 52 (9.5) | 78 (10.5) | |
Smoking status (n, %) | 0.19 | |||
Never smoker | 481 (48.1) | 257 (46.9) | 363 (49.0) | |
Former smoker who quitted > 20 years ago | 124 (12.4) | 74 (13.5) | 112 (15.1) | |
Former smoker who quitted 5 to < 20 years ago | 149 (14.9) | 83 (15.2) | 100 (13.5) | |
Former smoker who quitted 0 to < 5 years ago | 60 (6.0) | 29 (5.3) | 31 (4.2) | |
Current smoker smoking 0 to < 15 g tobacco/day | 84 (8.4) | 49 (8.9) | 60 (8.1) | |
Current smoker smoking 15 to < 30 g tobacco/day | 97 (9.7) | 49 (8.9) | 60 (8.1) | |
Current smoker smoking > 30 g tobacco/day | 5 (0.5) | 7 (1.3) | 15 (2.0) | |
Alcohol consumption (g/day, median, IQR) † | 6.0 (0–14.4) | 5.6 (0–12.6) | 4.8 (0–13.7) | 0.80 |
Physical activity (n, %) ‡ | 0.17 | |||
Inactive | 204 (20.4) | 114 (20.8) | 157 (21.2) | |
Sedentary | 438 (43.8) | 270 (49.3) | 343 (46.3) | |
Vigorously active | 358 (35.8) | 164 (39.9) | 241 (32.5) | |
BMI (kg/m2, median, IQR) | 27.4 (25.0–30.1) | 27.1 (24.5–30.1) | 27.2 (24.9–30.1) | 0.39 |
Categorized BMI (n, %) | < 0.001 | |||
< 25 kg/m2 | 251 (25.1) | 167 (30.5) | 195 (26.3) | |
25 to < 30 kg/m2 | 483 (48.3) | 235 (42.9) | 350 (47.2) | |
≥ 30 kg/m2 | 266 (26.6) | 146 (26.6) | 196 (26.5) | |
Dietary factors (n, %) | ||||
Fruit consumption, < once/day | 391 (39.2) | 192 (35.0) | 287 (38.7) | 0.26 |
Vegetable consumption, < once/day | 656 (65.6) | 341 (62.2) | 461 (62.2) | 0.25 |
Meat consumption, ≥ once/day | 349 (34.9) | 178 (31.5) | 247 (33.3) | 0.59 |
Leukocyte composition (mean, SD) ┼ | ||||
CD8+ T cells | 0.07 (0.05–0.10) | 0.09 (0.07–0.12) | 0.06 (0.04–0.09) | < 0.001 |
CD4+ T cells | 0.16 (0.12–0.20) | 0.17 (0.13–0.20) | 0.16 (0.12–0.20) | 0.01 |
NK cells | 0.91 (0.07–0.12) | 0.09 (0.07–0.12) | 0.10 (0.07–0.13) | 0.18 |
B cells | 0.06 (0.05–0.07) | 0.07 (0.06–0.08) | 0.06 (0.04–0.07) | < 0.001 |
Monocytes | 0.10 (0.09–0.11) | 0.10 (0.09–0.11) | 0.07 (0.06–0.08) | < 0.001 |
Granulocytes | 0.55 (0.48–0.60) | 0.54 (0.47–0.59) | 0.56 (0.50–0.62) | < 0.001 |
8-isoprostane (nmol/mmol creatinine, median, IQR) | 0.19 (0.13–0.26) | 0.21 (0.16–0.27) | 0.21 (0.16–0.28) | < 0.001 |
Prevalent cancer cases (n, %) | 75 (7.5) | 32 (6.0) | 57 (7.7) | 0.46 |
Prevalent CVD cases (n, %) ^ | 218 (21.8) | 107 (20.2) | 137 (18.5) | 0.24 |
Prevalent diabetes cases (n, %) | 155 (15.5) | 89 (16.8) | 108 (14.6) | 0.64 |
Prevalent asthma cases (n, %) | 74 (7.4) | 23 (4.3) | 49 (6.6) | 0.19 |