Table 4.
IV robustness analyses: different specifications of the instrument.
| Dependent variable | (1) KS3 |
(2) Systolic blood pressure |
(3) Diastolic blood pressure |
|||
|---|---|---|---|---|---|---|
| Coeff | p-Value | Coeff | p-Value | Coeff | p-Value | |
| Panel A: Mutually exclusive instruments | ||||||
| Coefficient and p-value | 0.039 | 0.695 | 0.299 | 0.015 | 0.205 | 0.026 |
| 95% confidence interval | [−0.16, 0.23] | [0.06, 0.54] | [0.03, 0.39] | |||
| First stage F-statistic | 8.90 | 8.20 | 8.20 | |||
| IV: p-value, Hausman test | 0.183 | 0.962 | 0.482 | |||
| IV: p-value, Hansen J-test | 0.862 | 0.574 | 0.531 | |||
| Panel B: 32 independent SNPs | ||||||
| Coefficient and p-value | −0.035 | 0.643 | 0.354 | <0.001 | 0.093 | 0.195 |
| 95% confidence interval | [−0.18, 0.11] | [0.16, 0.54] | [−0.05, 0.23] | |||
| First stage F-statistic | 4.93 | 4.38 | 4.38 | |||
| IV: p-value, Hausman test | 0.508 | 0.176 | 0.859 | |||
| IV: p-value, Hansen J-test | 0.039 | 0.594 | 0.602 | |||
| Panel C: No. of adiposity-increasing alleles for each of the 32 SNPs | ||||||
| Coefficient and p-value | −0.031 | 0.647 | 0.372 | <0.001 | 0.168 | 0.011 |
| 95% confidence interval | [−0.16, 0.10] | [0.20, 0.55] | [0.04, 0.30] | |||
| First stage F-statistic | 3.11 | 2.63 | 2.63 | |||
| IV: p-value, Hausman test | 0.277 | 0.082 | 0.267 | |||
| IV: p-value, Hansen J-test | 0.422 | 0.531 | 0.144 | |||
| Panel D: Weighted allelic score | ||||||
| Coefficient and p-value | 0.080 | 0.370 | 0.452 | <0.001 | 0.174 | 0.038 |
| 95% confidence interval | [−0.10, 0.26] | [0.23, 0.68] | [0.01, 0.34] | |||
| First stage F-statistic | 116.7 | 101.3 | 101.3 | |||
| IV: p-value, Hausman test | 0.049 | 0.045 | 0.482 | |||
| IV: p-value, Hansen J-test | – | – | – | |||
| Panel E: Selected instruments in weighted score | ||||||
| Coefficient and p-value | 0.116 | 0.239 | 0.542 | <0.001 | 0.182 | 0.037 |
| 95% confidence interval | [−0.08, 0.31] | [0.30, 0.78] | [0.01, 0.35] | |||
| First stage F-statistic | 96.59 | 91.68 | 91.68 | |||
| IV: p-value, Hausman test | 0.029 | 0.444 | 0.444 | |||
| IV: p-value, Hansen J-test | – | – | – | |||
| Panel F: Using only FTO and MC4R | ||||||
| Coefficient and p-value | 0.139 | 0.312 | 0.666 | <0.001 | 0.230 | 0.082 |
| 95% confidence interval | [−0.13, 0.41] | [0.30, 1.03] | [−0.03, 0.49] | |||
| First stage F-statistic | 24.54 | 21.81 | 21.81 | |||
| IV: p-value, Hausman test | 0.078 | 0.011 | 0.340 | |||
| IV: p-value, Hansen J-test | 0.403 | 0.192 | 0.147 | |||
| Number of observations | 4844 | 4047 | 4047 | |||
Notes: See notes to Table 3. Panel A shows the IV estimate using the mutually exclusive instrumental variables, indicating the number of adiposity-increasing alleles carried by each child. Panel B uses the 32 independent SNPs as 32 instruments. Panel C specifies the number of adiposity-increasing alleles for each SNP as separate instruments (i.e. 64 instruments). Panel D uses a weighted allelic score, where the weights at each locus are defined by the effect size of the variant on adiposity, as estimated in an independent meta-analysis (Speliotes et al., 2010). All analyses control for ancestry-informative principal components. 95% confidence intervals in square brackets; p-value is p-value for standard t-ratio.