Table 1.
Epidemiologic parameters and the blood lead level (PbB), mean, maximum and minimum PbB, zinc protoporphyrin concentration in blood (ZPP) mean, maximum and minimum ZPP and delta-aminolevulinic acid (ALA) in urine
| Low Se group n = 162 |
High Se group n = 162 |
Relative change (%) | p value | |||
|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | |||
| Age | 39.0 | 11.0 | 38.0 | 9.78 | −2 | 0.418 |
| Years of work | 13.7 | 11.4 | 12.0 | 10.4 | −13 | 0.157 |
| Height (cm) | 176 | 6.32 | 176 | 5.83 | 0 | 0.608 |
| Weight (kg) | 83.8 | 14.8 | 85.4 | 12.4 | 2 | 0.308 |
| Systolic blood pressure (mmHg) | 121.91 | 5.52 | 121.17 | 5.42 | −1 | 0.058 |
| Diastolic blood pressure (mmHg) | 78.52 | 4.66 | 78.09 | 4.93 | −1 | 0.418 |
| PbB (μg/dl) | 33.83 | 9.43 | 31.85 | 9.87 | −6 | 0.030 |
| PbBmean (μg/dl) | 32.55 | 8.86 | 30.87 | 9.22 | −5 | 0.069 |
| PbBmin (μg/dl) | 20.12 | 9.71 | 19.20 | 9.42 | −5 | 0.397 |
| PbBmax (μg/dl) | 43.18 | 11.47 | 41.45 | 12.12 | −4 | 0.087 |
| ZPP (μg/g Hb) | 4.28 | 2.25 | 4.05 | 1.90 | −5 | 0.324 |
| ZPPmean (μg/g Hb) | 4.81 | 2.38 | 4.50 | 2.26 | −6 | 0.237 |
| ZPPmin (μg/g Hb) | 2.87 | 1.52 | 2.77 | 1.19 | −4 | 0.512 |
| ZPPmax (μg/g Hb) | 7.89 | 4.72 | 7.36 | 5.00 | −7 | 0.089 |
| ALA (mg/l) | 5.38 | 1.73 | 4.77 | 1.95 | −11 | 0.386 |
PbB and ZPP mean levels of Pb and ZPP in the blood determined simultaneously with the biochemical analysis; PbB mean and ZPP mean mean levels of Pb and ZPP in the blood calculated based on the values determined, on average, every 3 months during the 5 years of observation before the study; PbB min, PbB max, ZPP min, and ZPP max mean of the maximal and minimal levels of Pb and ZPP in the blood collected from each worker calculated based on the values determined, on average, every 3 months during the 5 years of observation