Table 5.
Observed and instrumental variable analysis of the maternal homocysteine offspring birthweight association
| Analysis | Observed change in birthweight (g) per SD change in total homocysteine |
Instrumental variable estimate of change in birthweight (g) per SD change in total homocysteine |
P1 | ||||
|---|---|---|---|---|---|---|---|
| Effect size (g) | 95% CI | P | Effect size (g) | 95% CI | P | ||
| Unadjusted | |||||||
| PMNS | –39 | –71, –7 | 0.02 | –89 | –295, 118 | 0.40 | 0.63 |
| Parthenon | –74 | –112, –36 | <0.001 | –268 | –462, –75 | 0.007 | 0.045 |
| Meta-analysis | –56 | –81, –32 | <0.001 | –198 | –338, –57 | 0.006 | 0.044 |
| Heterogenity P (I2%) | 0.16 (48.4) | 0.20 (33.5) | |||||
| Adjusted for gestational age and gender | |||||||
| PMNS | –22 | –50, 5 | 0.11 | –84 | –259, 90 | 0.34 | 0.48 |
| Parthenon | –57 | –92, –21 | 0.002 | –309 | –488, –131 | 0.001 | 0.005 |
| Meta-analysis | –40 | –62, –17 | <0.001 | –224 | –349, –100 | <0.001 | 0.003 |
| Heterogenity P (I2%) | 0.15 (51.0) | 0.078 (68.0) | |||||
| Additionally adjusted for fetal genotype | |||||||
| PMNS | –27 | –55, 1 | 0.06 | –135 | –324, 53 | 0.16 | 0.25 |
| Parthenon | –58 | –94, –22 | 0.002 | –308 | –490, –125 | 0.001 | 0.006 |
| Meta-analysis | –43 | –65, –20 | <0.001 | –248 | –378, –118 | <0.001 | 0.002 |
| Heterogenity P (I2%) | 0.29 (37.9) | 0.076 (39.4) | |||||
P1: P-value for the Durbin-Wu-Hausman test for the difference between the estimates from observed and instrumental variable analysis.