Table 3.
Odds ratio (OR) with 95% confidence interval (CI) of developing multiple sclerosis for subjects with different combinations of adolescent body mass index (BMI) and infectious mononucleosis (IM) status. Attributable proportion due to interaction (AP), relative excess risk due to interaction (RERI) and synergy index (SI) for the interaction between adolescent BMI and past IM
| BMI > 27 | IM | ca/coa | OR (95% CI)b | OR (95% CI)c | P |
|---|---|---|---|---|---|
| EIMS | Past IM | ||||
| − | − | 1325/3277 | 1.0 (–) | 1.0 (–) | |
| + | − | 129/187 | 1.7 (1.3–2.1) | 1.7 (1.4–2.2) | <0.0001 |
| − | + | 289/407 | 1.8 (1.5–2.1) | 1.8 (1.5–2.2) | <0.0001 |
| + | + | 37/14 | 6.6 (3.6–12.4) | 8.1 (4.2–15.0) | <0.0001 |
| Interaction term | 2.2 (1.1–4.4) | 2.6 (1.3–5.2) | 0.009 | ||
| AP | 0.6 (0.2–0.8) | 0.7 (0.3–0.8) | |||
| RERI | 4.2 (1.1–9.9) | 5.5 (1.7–12.8) | |||
| SI | 3.9 (1.7–8.6) | 4.6 (2.0–10.2) | |||
| IM after age 10 | |||||
| − | − | 1325/3277 | 1.0 (–) | 1.0 (–) | |
| + | − | 129/187 | 1.7 (1.3–2.1) | 1.7 (1.4–2.2) | <0.0001 |
| − | + | 208/249 | 2.1 (1.7–2.6) | 2.1 (1.7–2.6) | <0.0001 |
| + | + | 28/6 | 12.0 (4.9–29.1) | 14.7 (5.9–36.6) | <0.0001 |
| Interaction term | 3.4 (1.3–8.6) | 4.0 (1.5–10.4) | 0.005 | ||
| AP | 0.8 (0.4–0.8) | 0.8 (0.4–0.9) | |||
| RERI | 9.2 (2.1–26.3) | 11.9 (3.1–33.7) | |||
| SI | 6.2 (2.2–17.0) | 7.4 (2.6–20.6) | |||
| GEMS | Past IM | ||||
| − | − | 3644/3574 | 1.0 (–) | ||
| + | − | 196/152 | 1.3 (1.0–1.6) | <0.0001 | |
| − | + | 618/306 | 2.0 (1.7–2.3) | 0.002 | |
| + | + | 44/7 | 6.3 (2.8–13.9) | <0.0001 | |
| Interaction termd | 2.4 (1.1–5.6) | 0.04 | |||
| AP | 0.7 (0.2–0.8) | ||||
| RERI | 5.5 (1.2–16.7) | ||||
| SI | 4.6 (2.0–10.2) | ||||
| IM after age 10 | |||||
| − | − | 3644/3574 | 1.0 (–) | ||
| + | − | 196/152 | 1.3 (1.0–1.6) | 0.03 | |
| − | + | 505/245 | 1.8 (1.8–2.4) | <0.0001 | |
| + | + | 37/4 | 9.3 (3.3–26.1) | <0.0001 | |
| Interaction term | 3.5 (1.2–10.2) | 0.02 | |||
| AP | 0.7 (0.09–0.8) | ||||
| RERI | 6.9 (0.8–27.2) | ||||
| SI | 6.2 (1.9–20.4) |
aNumber of exposed cases and controls; badjusted for matching variables, origin and smoking habits; cadjusted for matching variables, origin, smoking habits, HLA-DRB1*15 and HLA-A*02; dindicates interaction on the multiplicative scale.