Table 4.
Crude and adjusted RR of having ADHD symptoms at 4 years of age in relation to in utero exposure to HCB [coefficient (95% CI)].
| Exposure | Unadjusted (n = 377) | Adjusteda (n = 377) | Adjusted for other OCsb (n = 377) | Menorca cohortb (n = 329) |
|---|---|---|---|---|
| HCB category | ||||
| Referencec | 1 | 1 | 1 | 1 |
| 0.5–0.99 ng/mL | 1.19 (0.58–2.42) | 1.23 (0.54–2.78) | 1.47 (0.63–3.46) | 1.38 (0.57–3.32) |
| 1–1.49 ng/mL | 1.73 (0.77–3.91) | 2.28 (0.88–5.96) | 2.74 (1.01–7.45)* | 2.17 (0.73–6.49) |
| ≥ 1.5 ng/mL | 2.05 (0.90–4.67)** | 2.71 (1.05–6.96)* | 3.43 (1.24–9.51)* | 3.11 (1.01–9.55)* |
| HCB (ng/mL)d | 1.49 (0.99–2.24)** | 1.63 (1.02–2.63)* | 1.88 (1.13–3.14)* | 1.77 (1.00–3.11)* |
a
Adjusted for age, cohort, sex, maternal education, paternal education, tobacco and alcohol exposure, maternal age in years, and type and duration of breast-feeding (see “Population and Methods”).
b
Adjusted for same variables above and PCBs, p,p′-DDE and p,p′-DDT.
c
Reference group: < 0.5 ng/mL.
d
Natural logarithmic transformed HCB concentration.
*
p < 0.05
**
p < 0.10.