Risks of low-molecular-weight proteinuria in male workers with CdU<BMDL5 (6.6 μg/g creatinine) according to cumulative smoking
| Categories of pack-years | |||||
| Never smokers | <10 | 10–20 | >20 | p Value | |
| N* | 232 | 61 | 69 | 39 | |
| Age, mean (SD), years | 44.0 (10.0) | 40.1 (8.8) | 42.0 (10.7) | 52.5 (6.7)§ | <0.001 |
| Cd in urine | |||||
| Median (IQR), μg/g creatinine adjusted for CrU | 1.40 (0.57–2.90) | 1.23 (0.55–2.75) | 1.15 (0.52–3.08) | 2.63 (1.52–3.76)§ | 0.004 |
| RBP in urine adjusted for age, CrU and CdU† | |||||
| Median (IQR), μg/g creatinine | 113 (78–160) | 135 (99.8–178) | 143 (96.7–200)§ | 141 (86–205) | 0.03 |
| N>285 μg/g creatinine (%) | 12 (5.2) | 3 (4.9) | 10 (14.5) | 4 (10.3) | 0.03 |
| OR (95% CI) | 1.00 (1.0 to 1.0) | 0.95 (0.26 to 3.47) | 3.11 (1.28 to 7.55) | 2.10 (0.64 to 6.86) | |
| β2-Microglobulin in urine adjusted for CrU and CdU†, ‡ | |||||
| Median (IQR), μg/g creatinine | 78.7 (54.5–120) | 77.0 (55.2–144) | 92.7 (62.3–149) | 121 (80.7–231)§ | 0.02 |
| N>295 μg/g creatinine (%) | 8 (5.1) | 3 (7.0) | 3 (5.9) | 2 (7.7) | 0.59 |
| OR (95% CI) | 1.0 (1.0 to 1.0) | 1.41 (0.36 to 5.55) | 1.17 (0.30 to 4.60) | 3.41 (0.31 to 7.81) | |
p Values indicate the level of statistical significance in the χ2 test for trend (prevalences) or in one-way ANOVA.
↵* For β2-mU, n=158, 43, 51 and 26.
↵† Adjustment based on the multiple regression analysis of data in workers with CdU<6.6 μg/g creatinine.
↵‡ β2-mU>20 μg/g CrU.
↵§ Denotes statistical significance (p<0.05) by comparison with never smokers (Tukey-Kramer post hoc test).
β2-mU, concentration of β2-microglobulin in urine; BMDL5, benchmark dose lower limit for a 5% excess in the background prevalence of abnormal RBPU and β2-mU; CdU, urinary cadmium; RBPU, retinol-binding protein.