TABLE 6.
Risk of Childhood Leukemia in Relation to Outdoor Contact Voltage (VW-E), NCCLS Contact Current Study
| Exposure variables | Cases (no.) | Controls (no.) | Odds ratioa | 95% CI |
|---|---|---|---|---|
| Continuous variable (per 100 mV) | 219 | 257 | 0.96 | 0.85–1.09 |
| Categorical | ||||
| Quartile 1 (0.00–35.8 mV) | 59 | 65 | 1.00 | |
| Quartile 2 (35.8–89.7 mV) | 61 | 64 | 1.17 | 0.70, 1.96 |
| Quartile 3 (89.7–166.8 mV) | 54 | 63 | 1.02 | 0.61, 1.70 |
| Quartile 4 (≥166.8 mV) | 45 | 65 | 0.73 | 0.43, 1.25 |
| Binary (90th percentile) | ||||
| Unexposed (<291.2 mV) | 196 | 231 | 1.00 | |
| Exposed (≥291.2 mV) | 23 | 26 | 0.89 | 0.48, 1.63 |
a
All odds ratios were adjusted for household income, age, sex, Hispanic ethnicity and mother’s race.