Table 3.
Mean difference in eGFR measures, in mL/min/1.73 m2, by quartiles of urine metal concentrations, using three approaches to urine concentration adjustment.
| Urine concentration adjustment method | |||
|---|---|---|---|
|
| |||
| μg/L β (95% CI) | μg/g Creatinine β (95% CI) | μg/μOsm/kg β (95% CI) | |
| Cadmium | CKiD bedside serum creatinine-based eGFR | ||
| Q1 | 0 (reference) | 0 (reference) | 0 (reference) |
| Q2 | −0.3 (−4.2, 3.5) | 3.5 (−0.4, 7.3) | −0.7 (−4.6, 3.3) |
| Q3 | −0.8 (−4.8, 3.1) | 7.8 (3.9, 11.8) | −1.1 (−5.1, 2.9) |
| Q4 | −1.1 (−5.2, 3.1) | 7.2 (3.0, 11.4) | −1.2 (−5.3, 2.9) |
| p-Trenda | 0.62 | 0.001 | 0.62 |
| Cadmium | Filler serum cystatin-C-based eGFR | ||
| Q1 | 0 (reference) | 0 (reference) | 0 (reference) |
| Q2 | 2.0 (−2.0, 6.0) | 1.8 (−2.3, 5.8) | 2.6 (−1.5, 6.7) |
| Q3 | 0.5 (−3.6, 4.6) | 5.9 (1.8, 10.0) | 1.9 (−2.2, 6.1) |
| Q4 | 0.7 (−3.6, 5.1) | 4.9 (0.4, 9.3) | −0.4 (−4.7, 3.9) |
| p-Trend | 0.99 | 0.03 | 0.47 |
| Thallium | CKiD bedside serum creatinine-based eGFR | ||
| Q1 | 0 (reference) | 0 (reference) | 0 (reference) |
| Q2 | 2.9 (−1.0, 6.8) | 1.2 (−2.5, 5.0) | 2.3 (−1.6, 6.3) |
| Q3 | 0.7 (−3.2, 4.7) | 6.5 (2.7, 10.2) | 2.6 (−1.3, 6.5) |
| Q4 | 0.0 (−4.0, 4.1) | 10.9 (7.0, 14.8) | 1.3 (−2.8, 5.3) |
| p-Trend | 0.71 | <0.001 | 0.67 |
| Thallium | Filler serum cystatin-C-based eGFR | ||
| Q1 | 0 (reference) | 0 (reference) | 0 (reference) |
| Q2 | 0.6 (−3.5, 4.7) | 0.3 (−3.8,4.3) | 1.3 (−2.8, 5.4) |
| Q3 | −1.8 (−5.9, 2.3) | 2.9 (−1.1, 7.0) | −1.3 (−5.3, 2.8) |
| Q4 | 1.0 (−3.2, 5.2) | 4.4 (0.2,8.6) | 0.4 (−3.8, 4.6) |
| p-Trend | 0.80 | 0.02 | 0.85 |
| Uranium | CKiD bedside serum creatinine-based eGFR | ||
| Q1 | 0 (reference) | 0 (reference) | 0 (reference) |
| Q2 | 0.5 (−3.4, 4.4) | 1.9 (−2.0, 5.8) | −1.8 (−5.6, 2.1) |
| Q3 | −0.7 (−4.6, 3.3) | 2.9 (−1.1, 6.9) | −1.4 (−5.3, 2.6) |
| Q4 | −3.7 (−7.7, 0.3) | 3.8 (−0.3, 7.9) | −3.9 (−7.8, 0.1) |
| p-Trend | 0.03 | 0.08 | 0.07 |
| Uranium | Filler serum cystatin-C-based eGFR | ||
| Q1 | 0 (reference) | 0 (reference) | 0 (reference) |
| Q2 | 0.9 (−3.2, 5.0) | 0.4 (−3.7, 4.5) | −0.4 (−4.4, 3.7) |
| Q3 | −2.4 (−6.5,1.7) | 1.5 (−2.7, 5.7) | −4.9 (−9.0, −0.8) |
| Q4 | −1.2 (−5.4, 2.9) | 1.5 (−2.8, 5.8) | −1.8 (−6.0, 2.3) |
| p-Trend | 0.39 | 0.46 | 0.36 |
Adjusted for age, sex, maternal education (none/primary, secondary, >secondary), monthly household income (<3000 pesos, ≥3000 pesos, unknown/no response), participant smoking status (never, former [not in past month], current [at least once in past month]), BMI, systolic blood pressure and natural log blood lead.
p-Value for trend based on Wald test from regression model in which quartile medians were entered.Quartiles 1, 2 and 3 cut-points are as follows: <0.149, <0.237, and <0.371 for cadmium in μg/L; <0.149, <0.220, and <0.333 for cadmium in μg/g creatinine; <0.233, <0.328, and <0.511 for cadmium in μg/μOsm/kg; <0.209, <0.332, and <0.453 for thallium in μg/L; <0.192, <0.269, <0.378 for thallium in μg/g creatinine; <0.318, <0.417, and <0.550 for thallium in μg/μOsm/kg; <0.025, <0.044, and <0.076 for uranium in μg/L; <0.026, <0.042, and <0.061 for uranium in μg/g creatinine; <0.039, <0.062, and <0.098 for uranium in μg/μOsm/kg.β reflects the difference in serum creatinine and cystatin C comparing metal quartiles 2–4 to the lowest quartile.