Table 4.
Odds ratios and 95% confidence intervals for the association between interpregnancy interval (IPI) and ADHD, stratified by the comorbid diagnosis of autism spectrum disorder (ASD) in the case
| Interpregnancy interval (mo) | Comorbid ASD diagnosis in the case (N = 5238) | No ASD diagnosis in the case (N = 38 163) | P interaction b |
|---|---|---|---|
| ORa (95% CI) | ORa (95% CI) | ||
| <6 | 0.34 (0.14, 0.83) | 1.32 (1.13, 1.55) | <.01 |
| 6–11 | 0.80 (0.42, 1.50) | 1.00 (0.90, 1.11) | .49 |
| 12–23 | 0.62 (0.37, 1.05) | 1.01 (0.92, 1.10) | .07 |
| 24–59 | 1.00 (Reference) | 1.00 (Reference) | -- |
| 60–119 | 0.76 (0.41, 1.39) | 1.11 (1.00, 1.23) | .23 |
| ≥120 | 1.24 (0.51, 3.01) | 1.18 (1.00, 1.38) | .91 |
| First-born, no IPI | 1.06 (0.69, 1.64) | 1.29 (1.20, 1.39) | .38 |
a
Adjusted for parental psychiatric diagnosis, maternal history of substance abuse, maternal immigration, maternal education, and paternal education.
b
Pinteraction, P-value for interaction.