Table 6.
Interactive association between dichotomized exposure to PCB-153 (concentrations above or below the 75th percentile) and ASD status modified by GSTM1 genotypes, along with sensitivity analysis results by fitting the final model with pairs of concentrations above LoD.
| GST M1 Genotype | n = 338 children (169 pairs) (Model with GSTM1 interaction) |
Sensitivity Analysis n = children in pairs with both concentrations above LoD (Model with GSTM1 interaction) |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Category of PCB-153 | ASD Cases (n) | TD Controls (n) | Unadjustedc | Adjustedd | ASD Cases (n) | TD Controls (n) | Unadjustede | Adjustedf | |||||
| MOR (95% CI)a | P-valueb | MOR (95% CI)a | P-valueb | MOR (95% CI)a | P-valueb | MOR (95% CI)a | P-valueb | ||||||
| D/Dg | ≥ 75th percentile | 13 | 5 | 1.82 (0.59, 5.59) | 0.29 | 2.55 (0.68, 9.62) | 0.17 | 7 | 3 | 2.10 (0.36, 12.12) | 0.41 | 2.99 (0.40, 22.39) | 0.29 |
| < 75th percentile | 39 | 31 | 4 | 5 | |||||||||
| I/I or I/Dh | ≥ 75th percentile | 21 | 35 | 0.60 (0.33, 1.10) | 0.10 | 0.25 (0.11, 0.59) | <0.01 | 9 | 15 | 0.48 (0.15, 1.49) | 0.20 | 0.19 (0.04, 0.92) | 0.04 |
| < 75th percentile | 92 | 89 | 19 | 14 | |||||||||
Note: ASD, autism spectrum disorder; CI, confidence interval; MOR, matched odds ratio; PCB, polychlorinated biphenyl; TD, typically developing.
MOR represents those in Q4 (≥75%) compared to those in Q1, Q2, and Q3 (< 75%) of PCB-153 concentration.
P-value from Wald statistic in conditional logistic regression (CLR) model. (child age and sex were study matching factors and accounted for in CLR models)
P-value for the interaction term in the unadjusted CLR model based on the full data set is 0.08.
P-value for the interaction term in the CLR model adjusted for consumption of yogurt and salt fish/pickled mackerel, and age of the father based on the full data set is <0.01.
P-value for the interaction term in the unadjusted CLR model based on the subset of pairs with both concentrations above LoD is 0.14.
P-value for the interaction term in the CLR model adjusted for consumption of yogurt and salt fish/pickled mackerel, and age of the father at child’s birth based on the subset (concentrations above LoD) is 0.09.
Indicates the null alleles for GSTM1.
Indicates the homozygote (I/I) or heterozygote (I/D) for GSTM1.