Table 3.
Adjusted associationsa of maternal blood arsenic with birth outcomes, stratified by maternal glucose tolerance status.
| Outcome and exposure | Normal (< 140 mg/dL) | Impaired glucose tolerance (≥ 140 mg/dL) | p-Value for interactionc | ||
|---|---|---|---|---|---|
| n | Estimate (95% CI)b | n | Estimate (95% CI)b | ||
| Birth weight | |||||
| As quartile 1d | 132 | 0 (reference) | 11 | 0 (reference) | |
| Quartile 2 | 120 | –21.0 (–134.2, 92.2) | 13 | –409.0 (–771.7, –46.3) | 0.33 |
| Quartile 3 | 118 | –112.9 (–228.3, 2.6) | 24 | –183.5 (–495.3, 128.3) | 0.76 |
| Quartile 4 | 115 | –115.3 (–235.6, 5.1) | 24 | –562.6 (–919.6, –205.7) | 0.20 |
| Per IQR increase in As | 485 | –68.6 (–123.4, –13.8) | 72 | –185.0 (–358.6, –11.4) | 0.62 |
| Gestational age | |||||
| As quartile 1 | 132 | 0 (reference) | 11 | 0 (reference) | |
| Quartile 2 | 120 | 0.00 (–0.31, 0.32) | 13 | –0.33 (–1.4, 0.75) | 0.70 |
| Quartile 3 | 118 | –0.12 (–0.44, 0.20) | 24 | –0.74 (–1.7, 0.22) | 0.49 |
| Quartile 4 | 115 | –0.33 (–0.66, 0.00) | 24 | –1.7 (–2.8, –0.60) | 0.06* |
| Per IQR increase in As | 485 | –0.07 (–0.22, 0.08) | 72 | –0.73 (–1.2, –0.23) | 0.04* |
| Birth weight for gestational age | |||||
| As quartile 1 | 132 | 0 (reference) | 11 | 0 (reference) | |
| Quartile 2 | 120 | –0.05 (–0.28, 0.18) | 13 | –0.81 (–1.5, –0.09) | 0.28 |
| Quartile 3 | 118 | –0.20 (–0.43, 0.03) | 24 | –0.10 (–0.73, 0.52) | 0.54 |
| Quartile 4 | 115 | –0.18 (–0.42, 0.07) | 24 | –0.70 (–1.4, 0.02) | 0.47 |
| Per IQR increase in As | 485 | –0.14 (–0.25, –0.03) | 72 | –0.21 (–0.56, 0.14) | 0.84 |
| Head circumference | |||||
| As quartile 1 | 127 | 0 (reference) | 11 | 0 (reference) | |
| Quartile 2 | 113 | –0.02 (–0.47, 0.43) | 13 | –1.2 (–2.5, 0.04) | 0.63 |
| Quartile 3 | 113 | –0.58 (–1.0, –0.13) | 23 | –0.75 (–1.8, 0.35) | 0.67 |
| Quartile 4 | 112 | –0.44 (–0.91, 0.04) | 24 | –1.9 (–3.1, –0.65) | 0.58 |
| Per IQR increase in As | 465 | –0.21 (–0.43, 0.01) | 71 | –0.67 (–1.3, –0.08) | 0.87 |
| aModels were adjusted for maternal blood Pb and Mn (smoothed), maternal age at child’s birth (smoothed), infant sex, race/ethnicity, parity, smoking during pregnancy, maternal education, prenatal vitamin use, and maternal hemoglobin at delivery. bEffect estimates represent change in birth outcomes for arsenic quartiles 2, 3, 4 compared to quartile 1; or interquartile range increase in arsenic (continuous loge-transformed concentrations, scaled to the interquartile range. cInteraction cross-product term between arsenic and impaired glucose tolerance. dArsenic quartile 1: < 0.97 μg/L, quartile 2: ≥ 0.97 to < 1.4 μg/L, quartile 3: ≥ 1.4 to < 2.3 μg/L, quartile 4: ≥ 2.3 μg/L. *Interaction p-value < 0.10. | |||||