Characteristics of the workers
| Characteristic | All workers | Stratified by thirds of the blood lead distribution | |||
| <3.1 µg/dL | 3.1–7.0 µg/dL | >7.0 µg/dL | P value | ||
| Number in category | 328 | 106 | 112 | 110 | |
| Number (%) with characteristic | |||||
| Current smoking | 96 (29.3) | 25 (23.6) | 38 (33.9) | 33 (30) | 0.24 |
| Current alcohol intake | 132 (40.2) | 38 (35.9) | 52 (46.4) | 42 (38.2) | 0.24 |
| High blood pressure | 34 (10.4) | 9 (8.5) | 18 (16.0) | 7 (6.4)* | 0.045 |
| Treated hypertension | 21 (6.4) | 7 (6.6) | 11 (9.8) | 3 (2.7)* | 0.10 |
| Diabetes mellitus | 7 (2.1) | 2 (1.9) | 3 (2.7) | 2 (1.8) | 0.89 |
| History of CV disease | 17 (5.2) | 8 (7.5) | 5 (4.5) | 4 (3.6) | 0.40 |
| Mean of characteristic | |||||
| Age (years) | 28.3±10.2 | 28.7±10.1 | 29.8±11.5 | 26.4±8.7* | 0.090 |
| Body mass index (kg/m2) | 28.6±6.2 | 29.3±6.5 | 29.1±6.3 | 27.5±5.6 | 0.027 |
| Waist to hip ratio | 0.97±0.07 | 0.97±0.07 | 0.98±0.07 | 0.95±0.07* | 0.032 |
| Systolic pressure (mm Hg) | 120.6±9.7 | 120.5±9.2 | 122.2±10.0 | 119.1±9.5* | 0.27 |
| Diastolic pressure (mm Hg) | 80.7±7.9 | 80.2±8.2 | 81.7±8.0 | 80.2±7.5 | 0.95 |
| Mean arterial pressure (mm Hg) | 94.0±7.7 | 93.7±7.9 | 95.2±7.8 | 93.1±7.4 | 0.62 |
| Total cholesterol (mg/dL) | 169.4±36.9 | 172.3±37.0 | 174.0±39.2 | 162.1±33.6* | 0.039 |
| HDL cholesterol (mg/dL) | 45.9±10.5 | 44.3±9.6 | 46.5±10.0 | 47.0±11.7 | 0.058 |
| Total to HDL cholesterol ratio | 3.88±1.21 | 4.08±1.29 | 3.90±1.15 | 3.66±1.16 | 0.011 |
| Insulin (μIU/mL) | 7.3 (3.9–12.7) | 7.5 (4.5–13.0) | 7.4 (4.0–13.0) | 6.8 (3.4–11.8) | 0.37 |
| Blood lead (μg/dL) | 4.54 (2.50–8.30) | 1.81 (1.30–2.60) | 4.60 (3.70–5.40)*** | 11.0 (8.90–12.2)*** | <0.0001 |
Average values are arithmetic (±SD) or geometric means (IQR). High blood pressure was a level of ≥140 mm Hg systolic, or ≥90 mm Hg diastolic, or use of antihypertensive drugs. Mean arterial pressure was diastolic pressure plus one-third of the difference between systolic and diastolic pressure. P values are for linear trend across thirds of the blood lead distribution.
Significance of the difference with the adjacent left column: *P≤0.05; ***P≤0.001.
CV, cardiovascular; HDL, high-density lipoprotein.