TABLE 4.
Unadjusted and adjusted associations between serum concentrations* of polychlorinated biphenyls and organochlorine pesticides and total thyroxine in pregnant women† (n = 333), Salinas Valley, California, 1999–2000
| Change in total thyroxine concentration (μg/dl) per 10-fold increase in exposure |
||||
| Unadjusted |
Adjusted‡ |
|||
| β | 95% CI§ | β | 95% CI | |
| Organochlorines (ng/g) | ||||
| p,p′-DDT§ | 0.08 | −0.16, 0.32 | 0.13 | −0.11, 0.36 |
| o,p′-DDT | 0.12 | −0.16, 0.39 | 0.17 | −0.11, 0.44 |
| p,p′-DDE§ | 0.04 | −0.29, 0.36 | 0.17 | −0.15, 0.49 |
| Hexachlorobenzene | −0.67 | −1.13, −0.20 | −0.51 | −0.97, −0.04 |
| PCB§ groupings | ||||
| ΣPCBs (ng/g)¶ | −0.53 | −1.30, 0.24 | −0.29 | −1.06, 0.47 |
| Toxic equivalents (pg/g) | −0.18 | −0.87, 0.51 | 0.26 | −0.45, 0.96 |
| Enzyme inducers (ng/g)# | −0.86 | −1.60, −0.11 | −0.31 | −1.10, 0.48 |
| Mono-ortho PCBs (ng/g)** | −0.19 | −0.86, 0.48 | −0.13 | −0.78, 0.53 |
| Wolff's method group 3†† | −0.97 | −1.66, −0.29 | −0.51 | −1.23, 0.22 |
| Individual PCB congeners (ng/g) | ||||
| PCB 18 | −0.23 | −0.73, 0.28 | −0.29 | −0.79, 0.20 |
| PCB 28 | −0.20 | −0.71, 0.32 | −0.27 | −0.78, 0.23 |
| PCB 44 | −0.58 | −1.09, −0.06 | −0.57 | −1.07, −0.07 |
| PCB 49 | −0.25 | −0.74, 0.24 | −0.31 | −0.79, 0.18 |
| PCB 52 | −0.38 | −0.90, 0.15 | −0.43 | −0.94, 0.08 |
| PCB 66 | −0.14 | −0.73, 0.45 | −0.17 | −0.75, 0.40 |
| PCB 74 | −0.25 | −0.95, 0.45 | 0.02 | −0.68, 0.71 |
| PCB 99 | −0.67 | −1.36, 0.02 | −0.28 | −0.99, 0.44 |
| PCB 101 | −0.40 | −0.86, 0.07 | −0.43 | −0.88, 0.03 |
| PCB 118 | −0.16 | −0.84, 0.52 | 0.26 | −0.43, 0.95 |
| PCB 138 | −0.42 | −1.01, 0.17 | −0.04 | −0.65, 0.57 |
| PCB 146 | −0.61 | −1.09, −0.14 | −0.34 | −0.83, 0.15 |
| PCB 153 | −0.77 | −1.37, −0.17 | −0.37 | −1.00, 0.26 |
| PCB 156 | −0.42 | −0.86, 0.03 | −0.05 | −0.52, 0.42 |
| PCB 180 | −0.77 | −1.33, −0.20 | −0.42 | −1.01, 0.17 |
| PCB 183 | −0.14 | −0.62, 0.35 | 0.15 | −0.34, 0.64 |
| PCB 187 | −0.41 | −0.90, 0.08 | −0.11 | −0.61, 0.39 |
| PCB 194 | −0.34 | −0.86, 0.18 | 0.07 | −0.48, 0.62 |
| PCB 199 | −0.14 | −0.60, 0.33 | 0.22 | −0.26, 0.70 |
All polychlorinated biphenyl and organochlorine concentrations are expressed on a lipid basis (ng/g lipids) and were log10-transformed. Toxic equivalents are expressed in pg/g lipids. Total thyroxine is expressed in μg/dl.
One participant with an invalid total thyroxine measurement was dropped.
Results were adjusted for age and prepregnancy body mass index.
CI, confidence interval; DDT, dichlorodiphenyl trichloroethane; DDE, dichlorodiphenyl dichloroethylene; PCB, polychlorinated biphenyl.
Sum for the 19 PCB congeners with a detection frequency greater than 75%.
Enzyme inducers include PCBs 99, 101, 118, 153, 156, 157, 167, 180, 183, 187, 194, 189, and 199.
Mono-ortho PCBs include PCBs 28, 66, 74, 118, 156, 157, 167, and 189.
Group 3 includes PCBs 99, 153, 180, 183, and 196.