Descriptive statistics for exposure variables and biologic monitoring results by group
| Exposure measure | Group | n | Mean (SD) | Range | p value* |
|---|---|---|---|---|---|
| *Student’s t test. | |||||
| †One chlorpyrifos subject had 0 days of exposure but met all criteria for inclusion. The next least exposed chlorpyrifos subject had 1.27 years of exposure. | |||||
| Historic cumulative chlorpyrifos (mg/m3* days) | CPF | 53 | 64.16 (59.97) | 0.00–220.36 | <0.0001 |
| Referent | 60 | 0.69 (2.51) | 0.00–15.98 | ||
| Duration of work in exposed areas (years) | CPF | 53 | 9.72 (6.12) | 0†–23.71 | <0.0001 |
| Referent | 60 | 0.10 (0.37) | 0–2.12 | ||
| Interim cumulative chlorpyrifos (mg/m3* days) | CPF | 53 | 6.13 (3.70) | 0.00–15.37 | <0.0001 |
| Referent | 60 | 0.00 (0.00) | 0.00–0.00 | ||
| Urine TCP (g/ml) | CPF | 53 | 0.251 (0.399) | 0.006–1.894 | <0.0001 |
| Referent | 60 | 0.008 (0.004) | 0.001–0.017 | ||
| TCP/Cr (μg/g-Cr) | CPF | 53 | 192.2 (311.8) | 8.8–1536.5 | <0.0001 |
| Referent | 60 | 6.2 (2.2) | 1.4–12.1 | ||
| Average BuChE over study year (mu/ml) | CPF | 52 | 7155 (1729) | 3286–10237 | <0.002 |
| Referent | 60 | 8183 (1631) | 4605–12848 | ||
| Ratio of lowest BuChE during study year to pre-exposure BuChE | CPF | 52 | 0.75 (0.26) | 0.03–1.21 | 0.0008 |
| Referent | 60 | 0.88 (0.09) | 0.64–1.00 | ||
| AChE (mu/ml) at baseline | CPF | 53 | 6923 (828) | 4940–8713 | 0.77 |
| Referent | 60 | 6967 (766) | 4366–8403 | ||
| AChE (mu/ml) at one year | CPF | 53 | 7149 (751) | 5450–9281 | 0.48 |
| Referent | 58 | 7253 (811) | 4917–9208 | ||