Table 4.
Relative risk ratios (RRR) from multinomial logistic regression and 95% confidence intervals (CI) of ASD and Non-TD (versus TD) in relation to phthalate metabolite concentrations (μg/L) during mid- to late pregnancy among mothers who took prenatal vitamins during the first month of pregnancy and those who did not
| Prenatal vitamin use (n = 105; TD = 61, ASD = 15, Non-TD = 29) | No prenatal vitamin use (n = 85; TD = 36, ASD = 26, Non-TD = 23) | P-value for interaction c | |||
|---|---|---|---|---|---|
| RRR a | 95% CI | RRR a | 95% CI | ||
| ASD versus TD | |||||
| MEP | 1.88 | (0.82, 4.27) | 0.77 | (0.42, 1.37) | 0.12 |
| MiBP | 0.44 | (0.21, 0.88)* | 0.71 | (0.32, 1.51) | 0.52 |
| MHiBP | 0.52 | (0.22, 1.20) | 0.61 | (0.27, 1.35) | 0.97 |
| MBP | 0.48 | (0.17, 1.30) | 0.90 | (0.35, 2.26) | 0.33 |
| MHBP | 0.53 | (0.18, 1.56) | 0.87 | (0.31, 2.36) | 0.43 |
| MBzP | 0.85 | (0.41, 1.73) | 0.69 | (0.37, 1.30) | 0.97 |
| MCPP | 0.41 | (0.20, 0.83)* | 1.33 | (0.60, 2.93) | 0.02 |
| MCOP | 0.49 | (0.27, 0.88)* | 1.17 | (0.66, 2.05) | 0.08 |
| MCNP | 0.85 | (0.50, 1.42) | 1.16 | (0.55, 2.43) | 0.47 |
| ΣDEHP b | 0.51 | (0.19, 1.36) | 1.14 | (0.50, 2.56) | 0.12 |
| Non-TD versus TD | |||||
| MEP | 1.53 | (0.97, 2.41)# | 1.28 | (0.76, 2.14) | 0.79 |
| MiBP | 1.18 | (0.51, 2.70) | 1.39 | (0.68, 2.83) | 0.84 |
| MHiBP | 1.20 | (0.45, 3.16) | 1.24 | (0.61, 2.50) | 1.00 |
| MBP | 1.48 | (0.63, 3.46) | 1.86 | (0.75, 4.61) | 0.66 |
| MHBP | 1.38 | (0.57, 3.32) | 1.87 | (0.70, 4.97) | 0.72 |
| MBzP | 1.47 | (0.82, 2.62) | 1.16 | (0.65, 2.07) | 0.74 |
| MCPP | 0.93 | (0.54, 1.57) | 5.09 | (2.05, 12.6)* | 0.00 |
| MCOP | 0.99 | (0.58, 1.66) | 1.86 | (1.01, 3.39)* | 0.11 |
| MCNP | 0.88 | (0.53, 1.46) | 3.67 | (1.80, 7.48)* | 0.00 |
| ΣDEHP b | 1.26 | (0.72, 2.19) | 1.76 | (0.84, 3.65) | 0.30 |
aAdjusted for pre-pregnancy BMI, year of birth (linear and squared terms), and homeownership
bDue to high correlations among DEHP metabolites (r = 0.84–0.99), the molar sum of DEHP metabolites was only examined (ΣDEHP, μmol/L)
cP-value for interaction from the separate regression models
*p-value < 0.05, # p-value < 0.10
Note: MNP was excluded from this table because approximately 50% of samples had detectable concentrations. See Table 2 for abbreviations