Table 3.
Joint associations between ASD, folic acid (FA) intakea and air pollution (near roadway air pollution (NRP) and regional pollutants)b during the first trimester of pregnancy. N=606
| Poll. < or ≥ median |
FA < or ≥ 800 µg |
N ASD/ Control |
Unadjusted Model | Adjusted Modelc | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
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|
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| OR (95% CI) | OR (95% CI) | Additive interaction | Multiplicative Interaction | |||||||
|
| ||||||||||
| Expected Joint OR |
RERI p-value |
AP p-value |
Expected Joint OR |
Interaction p-value |
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|
|
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| NRP | Low | High | 85/71 | 1.0 (ref) | 1.0 (ref) | |||||
| Low | 78/61 | 1.07 (0.67, 1.69) | 0.88 (0.45, 1.73) | |||||||
| High | High | 81/80 | 0.85 (0.54, 1.32) | 0.75 (0.47, 1.19) | ||||||
| Low | 102/48 | 1.77 (1.11, 2.83) | 1.18 (0.58, 2.37) | 0.63 | 0.076 | 0.059 | 0.66 | 0.091 | ||
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|
|
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| NO2 | Low | High | 87/74 | 1.0 (ref) | 1.0 (ref) | |||||
| Low | 82/67 | 1.04 (0.67, 1.63) | 0.78 (0.40, 1.51) | |||||||
| High | High | 79/77 | 0.87 (0.56, 1.36) | 0.71 (0.44, 1.12) | ||||||
| Low | 98/42 | 1.98 (1.23, 3.20) | 1.38 (0.69, 2.75) | 0.49 | 0.011 | <0.001 | 0.55 | 0.008 | ||
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| PM10 | Low | High | 93/86 | 1.0 (ref) | 1.0 (ref) | |||||
| Low | 86/62 | 1.28 (0.83, 1.99) | 1.02 (0.53, 1.96) | |||||||
| High | High | 73/65 | 1.04 (0.67, 1.62) | 0.89 (0.56, 1.42) | ||||||
| Low | 94/47 | 1.85 (1.17, 2.92) | 1.28 (0.65, 2.51) | 0.91 | 0.294 | 0.262 | 0.91 | 0.319 | ||
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| PM2.5 | Low | High | 95/96 | 1.0 (ref) | 1.0 (ref) | |||||
| Low | 102/66 | 1.56 (1.03, 2.38) | 1.26 (0.66, 2.39) | |||||||
| High | High | 71/55 | 1.30 (0.83, 2.05) | 1.19 (0.74, 1.90) | ||||||
| Low | 78/43 | 1.83 (1.15, 2.93) | 1.33 (0.67, 2.68) | 1.45 | 0.793 | 0.798 | 1.50 | 0.742 | ||
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| Ozone | Low | High | 90/83 | 1.0 (ref) | 1.0 (ref) | |||||
| Low | 95/57 | 1.54 (0.99, 2.40) | 1.19 (0.61, 2.30) | |||||||
| High | High | 76/68 | 1.03 (0.66, 1.61) | 0.88 (0.56, 1.40) | ||||||
| Low | 85/52 | 1.51 (0.96, 2.38) | 1.08 (0.56, 2.08) | 1.07 | 0.971 | 0.971 | 1.05 | 0.923 | ||
Abbreviations: ASD, autism spectrum disorder; FA, folic acid; NRP, near roadway air pollution; NO2, nitrogen dioxide; PM2.5, particulate matter < 2.5 µm; PM10, particulate matter < 10 µm.
Folic acid intake is dichotomized at 800 µg (high vs. low) and includes all folic acid intake during the first month of pregnancy.
All pollutants were dichotomized at their whole pregnancy period median (high vs low) (NRP = 15.58 ppb; NO2 = 14.18 ppb; PM10 = 22.88 µg/cm3; PM2.5 = 12.40 µg/cm3; Ozone = 33.41 µg/cm3).
Model was adjusted for self-reported financial hardship between 3 months before pregnancy to time of interview (yes/no), child’s year of birth, vitamin A and zinc intake during the first month of pregnancy.