Table 1.
Baseline study population characteristics of women according to tertiles of serum free thiol concentrations (μmol/g).
| Variable | Total |
T1 (<4.60) |
T2 (4.60–5.40) |
T3 (>5.40) |
P-value |
|---|---|---|---|---|---|
| n = 2980 | n = 993 | n = 994 | n = 993 | ||
| Serum free thiols (μmol/g) | 4.97 ± 1.01 | 3.88 ± 0.60 | 5.01 ± 0.22 | 6.05 ± 0.56 | <0.001 |
| Age (years) | 50.9 [42.9; 59.5] | 56.6 [46.6; 68.1] | 50.7 [43.3; 58.3] | 46.7 [40.7; 53.8] | <0.001 |
| Ethnicity | |||||
| Caucasian, n (%) | 2,841 (96.0) | 954 (96.8) | 944 (95.4) | 943 (96.0) | |
| Asian, n (%) | 57 (1.9) | 16 (1.6) | 21 (2.1) | 20 (2.0) | 0.620 |
| Black, n (%) | 31 (1.0) | 8 (0.8) | 15 (1.5) | 8 (0.8) | |
| Other, n (%) | 29 (1.0) | 8 (0.8) | 10 (1.0) | 11 (1.1) | |
| BMI (kg/m2) | 25.6 [23.0; 28.9] | 26.9 [23.9; 30.3] | 25.5 [23.2; 28.6] | 24.6 [22.4; 27.5] | <0.001 |
| Waist circumference (cm) | 85 [78; 94] | 89 [81; 98] | 85 [78; 93] | 82 [76; 90] | <0.001 |
| Smoking | |||||
| Never, n (%) | 989 (33.3) | 349 (35.3) | 325 (32.8) | 315 (31.9) | |
| Former, n (%) | 1,140 (38.4) | 397 (40.1) | 386 (39.0) | 357 (36.1) | 0.009 |
| Current, n (%) | 838 (28.2) | 243 (24.6) | 279 (28.2) | 316 (32.0) | |
| Alcohol use | |||||
| No, n (%) | 942 (31.6) | 367 (37.0) | 298 (30.0) | 277 (27.9) | <0.001 |
| Yes, n (%) | 2,037 (68.4) | 625 (63.0) | 696 (70.0) | 716 (72.1) | |
| Blood pressure | |||||
| SBP (mmHg) | 117[108; 131] | 124[111; 139] | 116[107; 129] | 114[106; 126] | <0.001 |
| DBP (mmHg) | 70 [64; 76] | 71 [65; 77] | 69 [64; 75] | 69 [64; 75] | <0.001 |
| Co-morbidity | |||||
| CVD history, n (%) | 62 (2.1) | 31 (3.1) | 18 (1.8) | 13 (1.3) | 0.014 |
| Hypertension, n (%) | 763 (27.1) | 374 (39.2) | 224 (23.7) | 165 (18.1) | <0.001 |
| Diabetes, n (%) | 66 (2.2) | 34 (3.4) | 19 (1.9) | 13 (1.3) | 0.004 |
| Laboratory parameters | |||||
| Hemoglobin (mmol/L) | 8.1 ± 0.6 | 8.1 ± 0.6 | 8.1 ± 0.6 | 8.0 ± 0.6 | 0.703 |
| hs-CRP (mg/L) | 1.4 [0.6; 3.2] | 1.7 [0.8; 4.0] | 1.4 [0.7; 3.2] | 1.0 [0.5; 2.5] | <0.001 |
| Albumin (g/L) | 43.0 [42.0; 45.0] | 43.0 [41.0; 45.0] | 43.0 [42.0; 45.0] | 43.0 [42.0; 45.0] | <0.001 |
| Creatinine (μmol/L) | 74.9 [68.8; 82.1] | 77.0 [69.8; 85.2] | 76.0 [69.8; 83.2] | 72.9 [67.8; 80.1] | <0.001 |
| eGFR (mL/min/1.73 m2) | 92.7 ± 16.4 | 85.7 ± 17.2 | 93.4 ± 14.9 | 98.8 ± 14.3 | <0.001 |
| AST (U/L) | 21.0 [18.0; 24.0] | 21.0 [19.0; 25.0] | 21.0 [18.0; 24.0] | 20.0 [18.0; 23.0] | <0.001 |
| ALT (U/L) | 14.0 [11.0; 19.0] | 15.0 [11.0; 20.0] | 14.0 [11.0; 19.0] | 14.0 [11.0; 19.0] | 0.001 |
| Total cholesterol (mmol/L) | 5.5 ± 1.1 | 5.6 ± 1.0 | 5.5 ± 1.1 | 5.3 ± 1.1 | <0.001 |
| LDL-cholesterol (mmol/L) | 3.3 [2.7; 4.1] | 3.4 [2.8; 4.2] | 3.2 [2.5; 3.9] | 3.3 [2.5; 4.1] | 0.262 |
| HDL-cholesterol (mg/dL) | 52.5 [45.3; 60.6] | 51.6 [44.5; 59.6] | 53.0 [45.3; 61.4] | 52.8 [46.0; 61.0] | 0.055 |
| Triglycerides (mg/dL) | 89.3 [65.6; 122.7] | 96.1 [73.4; 127.3] | 88.8 [64.7; 126.1] | 81.8 [59.3; 112.5] | <0.001 |
| Glucose (mmol/L) | 4.7 [4.3; 5.1] | 4.7 [4.4; 5.3] | 4.7 [4.4; 5.1] | 4.6 [4.3; 5.1] | <0.001 |
| Follow-up (10 years) | |||||
| CV events, n (%) | 112 (3.8) | 53 (5.3) | 36 (3.6) | 23 (2.3) | 0.002 |
| Mortality, n (%) | 94 (3.2) | 51 (5.1) | 22 (2.2) | 21 (2.1) | <0.001 |
| Gynecological variables | |||||
| Menopausal status | |||||
| Premenopausal, n (%) | 1469 (49.3) | 350 (35.2) | 497 (50.0) | 622 (62.6) | <0.001 |
| Postmenopausal, n (%) | 1511 (50.7) | 643 (64.8) | 497 (50.0) | 371 (37.4) | |
| Age at menopause | |||||
| <37 years, n (%) | 38 (2.6) | 13 (2.1) | 19 (4.0) | 6 (1.7) | 0.350 |
| 37–41 years, n (%) | 122 (8.3) | 55 (8.7) | 36 (7.5) | 31 (8.6) | |
| 42–46 years, n (%) | 307 (20.9) | 139 (22.1) | 93 (19.4) | 75 (20.7) | |
| 47–50 years, n (%) | 469 (31.9) | 187 (29.7) | 156 (32.5) | 126 (34.8) | |
| 51–53 years, n (%) | 367 (24.9) | 156 (24.8) | 127 (26.5) | 84 (23.2) | |
| >53 years, n (%) | 168 (11.4) | 79 (12.6) | 49 (10.2) | 40 (11.0) | |
| Pregnancy in past | |||||
| No, n (%) | 685 (23.1) | 217 (22.0) | 227 (22.9) | 241 (24.4) | 0.444 |
| Yes, n (%) | 2279 (76.9) | 768 (78.0) | 765 (77.1) | 746 (75.6) | |
| No. of children | |||||
| 0, n (%) | 127 (5.4) | 38 (4.8) | 45 (5.7) | 44 (5.7) | <0.001 |
| 1, n (%) | 358 (12.0) | 99 (12.5) | 118 (15.1) | 141 (18.2) | |
| 2, n (%) | 1159 (49.4) | 350 (44.2) | 402 (51.3) | 407 (52.7) | |
| 3, n (%) | 497 (21.2) | 201 (25.4) | 152 (19.4) | 144 (18.6) | |
| 4, n (%) | 120 (5.1) | 56 (7.1) | 44 (5.6) | 20 (2.6) | |
| 5, n (%) | 47 (2.0) | 22 (2.8) | 12 (1.5) | 13 (1.7) | |
| ≥ 6, n (%) | 40 (1.7) | 25 (3.2) | 11 (1.4) | 4 (0.5) | |
| Hysterectomy, n (%) | 70 (2.4) | 20 (2.0) | 25 (2.5) | 25 (2.5) | 0.693 |
| Oophorectomy, n (%) | 32 (1.1) | 14 (1.4) | 9 (0.9) | 9 (0.9) | 0.909 |
| Current OCC use, n (%) | 395 (13.3) | 126 (12.7) | 134 (13.5) | 135 (13.6) | 0.816 |
| Current female hormone use | |||||
| Climacterium, n (%) | 111 (3.8) | 29 (2.9) | 44 (4.5) | 38 (3.8) | 0.208 |
| Other reasons, n (%) | 77 (2.6) | 20 (2.0) | 23 (2.3) | 34 (3.5) | 0.113 |
Data are presented as mean ± SD, median [IQR] in case of skewed variables or proportions n with corresponding percentages (%). Differences between tertiles of serum free thiol concentrations were tested using chi-square tests or Fisher's exact tests for nominal variables and one-way analysis of variance (ANOVA) in case of normally distributed continuous variables or Kruskal-Wallis tests in case of skewed continuous variables, as appropriate. P ≤ 0.05 were considered statistically significant. T1, tertile 1; T2, tertile 2; T3, tertile 3; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; CVD, cardiovascular disease; hs-CRP, high-sensitive C-reactive protein; eGFR, estimated glomerular filtration rate; AST, aspartate aminotransferase; ALT, alanine aminotransferase; LDL, low-density lipoprotein; HDL, high-density lipoprotein; OCC, oral contraceptives.