Table 2.
General characteristics of the overall study sample according to tertiles of circulating plasma lithium concentrations (n = 928).
| Plasma Concentration of Lithium (µg/L) | T1 ≤ 0.78 µg/L | T2 0.79–1.21 µg/L | T3 ≥ 1.22 µg/L | p * | |
|---|---|---|---|---|---|
| n (% male) a | 309 (61.2) | 309 (57.9) | 310 (52.9) | 0.11 | |
| Plasma concentration of lithium (µg/L) b | 0.63 (0.52, 0.70) | 0.95 (0.87, 1.08) | 1.60 (1.37, 2.10) | <0.0001 | |
| Age (years) c | 57 ± 12 | 62 ± 12 | 64 ± 12 | <0.0001 | |
| Body mass index (kg/m2) c | 28.2 ± 5.4 | 26.9 ± 4.4 | 27.3 ± 4.8 | 0.004 | |
| Waist circumference (cm) b | male | 100.3 (93.3, 108.8) | 99.1 (92.7, 106.5) | 100.2 (94.1, 108.5) | 0.58 |
| female | 92.0 (80.4, 101.0) | 88.4 (79.0, 97.4) | 89.3 (82.5, 98.8) | 0.19 | |
| Waist-to-hip ratio b | male | 0.99 (0.95, 1.02) | 0.99 (0.94, 1.03) | 0.99 (0.94, 1.03) | 0.94 |
| female | 0.88 (0.83, 0.93) | 0.87 (0.81, 0.91) | 0.88 (0.83, 0.93) | 0.20 | |
| Systolic blood pressure (mmHg) c | 141 ± 18 | 139 ± 19 | 140 ± 19 | 0.58 | |
| Diastolic blood pressure (mmHg) c | 86 ± 9 | 84 ± 9 | 85 ± 9 | 0.07 | |
| Prevalent hypertension a | 198 (64.1) | 178 (57.6) | 209 (67.4) | 0.04 | |
| HbA1c (%) c | 5.65 ± 0.60 | 5.73 ± 0.54 | 5.82 ± 0.67 | 0.002 | |
| Glucose (mg/dL) b | 96.0 (90.0, 105.0) | 98.0 (91.0, 105.0) | 98.0 (92.0, 105.0) | 0.25 | |
| Prevalent diabetes a | 17 (5.5) | 23 (7.4) | 38 (12.3) | 0.01 | |
| C-reactive protein (mg/L) b | 1.40 (0.45, 2.90) | 1.10 (0.45, 2.50) | 1.30 (0.45, 2.40) | 0.16 | |
| Triglycerides (mg/dL) b | 103.0 (77.0, 137.0) | 106.0 (73.0, 140.0) | 107.0 (80.0, 145.0) | 0.47 | |
| Total cholesterol (mg/dL) c | 223.5 ± 41.4 | 223.8 ± 38.9 | 221.2 ± 43.0 | 0.71 | |
| High-density-lipoprotein cholesterol (mg/dL) c | 62.7 ± 16.8 | 66.6 ± 18.6 | 65.1 ± 18.6 | 0.03 | |
| Low-density-lipoprotein cholesterol (mg/dL) c | 134.8 ± 33.2 | 131.4 ± 31.7 | 127.9 ± 35.1 | 0.04 | |
| Estimated glomerular filtration rate (mL/min/1.73 m2) c | 89.0 ± 14.3 | 84.1 ± 14.1 | 80.2 ± 16.4 | <0.0001 | |
| Creatinine (mg/dL) c | 0.87 ± 0.17 | 0.88 ± 0.16 | 0.91 ± 0.21 | 0.02 | |
| Current smokers a | 45 (14.6) | 47 (15.2) | 37 (11.9) | 0.46 | |
| Physical activity (MET-hours/week) b | 86.5 (54.8, 123.0) | 94.5 (63.3, 132.6) | 85.4 (55.1, 134.3) | 0.07 | |
| High education (≥11 years) a | 96 (31.1) | 112 (36.3) | 91 (29.4) | 0.33 | |
| Alcohol intake (g/day) b | 8.6 (2.8, 15.8) | 9.3 (3.8, 18.8) | 8.8 (3.2, 20.7) | 0.17 | |
| Glutamate-Oxalacetate-Transaminase (U/L) b | 26.0 (22.0, 30.0) | 26.0 (22.0, 30.0) | 26.0 (23.0, 31.0) | 0.21 | |
| Gamma-Glutamyl-Transferase (U/L) b | 25.0 (17.0, 35.0) | 23.0 (17.0, 35.0) | 26.0 (18.0, 44.0) | 0.07 | |
| Glutamate-Pyruvate-Transaminase (U/L) b | 24.0 (18.0, 32.0) | 21.0 (17.0, 29.0) | 22.0 (17.0, 30.0) | 0.12 | |
Values are a n (%), b median (Q1; Q3), c mean (95% CI). * p-values based on chi-square test, Kruskal–Wallis test (skewed variables) or general linear models (normally distributed variables). Abbreviations: CI, confidence interval; HbA1c, glycated hemoglobin; MET, metabolic equivalent of task; Q, quartile; T, tertile.