Table 1.
Description of reliability sample
| Controls (n=110) | Cases (n=111) | |
|---|---|---|
| Non-Hispanic White Race; n (%) | 96 (87) | 98 (88) |
| Current Smoker; n (%) | 9 (8) | 5 (5) |
| Age at first toenail sample collection, y; Mean (std) | 44.1 (3.8) | 43.6 (3.5) |
| Age at second toenail sample collection, y; Mean (std) | 51.7 (3.8) | 51.6 (3.5) |
| Years between sample collections; Mean (range) | 7.6 (4.4–10.6) | 8.0 (4.6–10.6) |
| Baseline metal levels (μg/g); Geometric Mean (IQR)a | ||
| Arsenic | 0.054 (0.038–0.075) | 0.055 (0.036–0.080) |
| Cadmium | 0.006 (0.003–0.011) | 0.007 (0.003–0.012) |
| Cobalt | 0.008 (0.004–0.013) | 0.007 (0.004–0.012) |
| Chromium | 0.247 (0.119–0.548) | 0.263 (0.148–0.578) |
| Copper | 3.64 (2.99–4.05) | 3.99 (3.16–4.55) |
| Iron | 14.9 (8.12–23.0) | 13.0 (7.89–18.5) |
| Mercury | 0.084 (0.045–0.222) | 0.087 (0.040–0.200) |
| Manganese | 0.228 (0.113–0.359) | 0.189 (0.098–0.342) |
| Molybdenum | 0.009 (0.005–0.013) | 0.008 (0.005–0.012) |
| Nickel | 0.589 (0.142–1.18) | 0.457 (0.144–1.13) |
| Lead | 0.134 (0.064–0.229) | 0.144 (0.062–0.262) |
| Antimony | 0.020 (0.010–0.036) | 0.021 (0.012–0.029) |
| Selenium | 0.941 (0.860–1.04) | 0.973 (0.869–1.06) |
| Tin | 0.091 (0.055–0.143) | 0.067 (0.038–0.114) |
| Vanadium | 0.010 (0.005–0.019) | 0.010 (0.005–0.018) |
| Zinc | 105 (91.8–116) | 104 (92.5–114) |
a
Includes those below the limit of quantification: Arsenic (4% visit 1, 8% visit 2); Cadmium (13% visit 1, 19% visit 2); Cobalt (2% visit 1, 5% visit 2); Chromium (33% visit 1, 46% visit 2); Copper (0% visit 1, 0% visit 2); Iron (3% visit 1, 3% visit 2); Mercury (7% visit 1, 9% visit 2); Manganese (5% visit 1, 9% visit 2); Molybdenum (52% visit 1, 63% visit 2); Nickel (9% visit 1, 14% visit 2); Lead (4% visit 1, 7% visit 2); Antimony (33% visit 1, 37% visit 2); Selenium (0% visit 1, 0% visit 2); Tin (1% visit 1, 5% visit 2); Vanadium (30% visit 1, 38% visit 2); Zinc (0% visit 1, 0% visit 2). IQR indicates interquartile range.