Table 2.
Difference in tremor scores by lead biomarker quintiles.
| Linear regression | Quintile 1 | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 | p-Trend |
|---|---|---|---|---|---|---|
| Blood lead | ||||||
| n | 244 | 178 | 122 | 153 | 110 | |
| Tremor score (mean ± SD) | 3.89 ± 1.02 | 3.96 ± 1.10 | 3.98 ± 0.74 | 4.01 ± 1.03 | 4.06 ± 1.11 | |
| Lead range (μg/dL) | 0 to 3 | 4 to 4 | 5 to 5 | 6 to 7 | 8 to 28 | |
| Crude model (95% CI) | 0 (reference) | 0.07 (–0.13, 0.26) | 0.09 (–0.13, 0.31) | 0.12 (–0.08, 0.33) | 0.18 (–0.05, 0.41) | 0.11 |
| Adjusteda model (95% CI) | 0 (reference) | 0.09 (–0.10, 0.29) | 0.06 (–0.16, 0.28) | 0.07 (–0.13, 0.27) | 0.07 (–0.16, 0.30) | 0.62 |
| Patella lead | ||||||
| n | 154 | 129 | 127 | 131 | 131 | |
| Tremor score (mean ± SD) | 3.97 ± 1.01 | 3.98 ± 1.05 | 3.93 ± 0.68 | 3.87 ± 0.88 | 4.22 ± 1.16 | |
| Lead range (μg/g) | –9 to 15 | 16 to 21 | 22 to 28 | 29 to 39 | 40 to 165 | |
| Crude model (95% CI) | 0 (reference) | 0.01 (–0.22, 0.23) | –0.04 (–0.27, 0.19) | –0.10 (–0.33, 0.12) | 0.24 (0.02, 0.47) | 0.07 |
| Adjusteda model (95% CI) | 0 (reference) | –0.07 (–0.30, 0.15) | –0.14 (–0.37, 0.09) | –0.22 (–0.45, 0.01) | –0.02 (–0.27, 0.22) | 0.67 |
| Tibia lead | ||||||
| n | 142 | 124 | 136 | 133 | 135 | |
| Tremor score (mean ± SD) | 3.88 ± 1.02 | 3.92 ± 1.06 | 4.00 ± 0.95 | 4.11 ± 0.98 | 4.02 ± 0.93 | |
| Lead range (μg/g) | –1 to 11 | 12 to 16 | 17 to 21 | 22 to 29 | 30 to 126 | |
| Crude model (95% CI) | 0 (reference) | 0.04 (–0.20, 0.28) | 0.12 (–0.11, 0.36) | 0.23 (–0.01, 0.46) | 0.14 (–0.10, 0.37) | 0.13 |
| Adjusteda model (95% CI) | 0 (reference) | 0.03 (–0.20, 0.26) | 0.03 (–0.20, 0.26) | 0.13 (–0.11, 0.36) | –0.07 (–0.32, 0.17) | 0.70 |
| aAdjusted for age, age squared, alcohol intake, cigarette pack-years, and education level. | ||||||