Table 4.
Controlled direct effects24 within the paternal line
| F1 |
F2 |
|||
|---|---|---|---|---|
| Father’s ever asthma | Offspring's ever asthma with nasal allergies | Offspring's ever asthma without nasal allergies | ||
| Generation | OR (95% CI) | RRR (95% CI) | RRR (95% CI) | |
| F0 | Grandmother’s ever asthma (present vs absent) | 3.08 (1.96–4.85) | – | – |
| Grandfather’s ever asthma (present vs absent) | 2.38 (1.51–3.75) | – | – | |
| Grandparents’ education levela (low vs high) | 0.96 (0.71–1.30) | – | – | |
| Grandmother’s smoking (vs not smoking) | ||||
| when the father was in utero | 0.82 (0.47–1.44) | 1.60 (0.95–2.68) | 1.08 (0.55–2.13) | |
| during other periods (or unknown smoking period) | 1.02 (0.62–1.67) | 1.24 (0.81–1.91) | 1.35 (0.87–2.09) | |
| F1 | Father’s age (1-year increase) | 0.99 (0.96–1.02) | – | – |
| Father’s ever asthma (present vs absent) | – | 2.37 (1.63–3.43) | 1.70 (1.14–2.53) | |
| Father’s education levela (low vs high) | – | 0.47 (0.27–0.83) | 0.87 (0.49–1.53) | |
| Father’s smoking initiation (vs not smoking) | ||||
| <15 years of age | – | 1.19 (0.74–1.90) | 1.43 (1.01–2.01) | |
| ≥15 years of age | – | 0.98 (0.71–1.36) | 0.88 (0.70–1.11) | |
| F2 | Offspring’s gender (female vs male) | – | 0.71 (0.59–0.84) | 0.83 (0.70–0.98) |
| Offspring’s age (1-year increase) | – | 1.00 (0.98–1.02) | 0.96 (0.94–0.99) | |
Comparison of the goodness-of-fit between the present mediation model and the cluster-robust (centre = cluster variable) two-level (father = level 2 unit) multinomial regression model (outcome: offspring’s ever asthma with or without nasal allergies; covariates: grandmother’s smoking, father’s ever asthma, education level and smoking initiation, offspring’s gender and age): P-value (Satorra-Bentler scaled chi-square test for nested models27 with 8 degrees of freedom) <0.0001. aThe estimates for the ‘unknown’ category are not shown.