Table 4.
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. HLA-DRB1*15 negative subjects. 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 | ||||
| − | − | 688/2748 | 1.0 (–) | 1.0 (–) | |
| + | − | 66/163 | 1.6 (1.2–2.2) | 1.6 (1.5–1.8) | 0.002 |
| − | + | 149/347 | 1.7 (1.4–2.1) | 1.8 (1.6–1.9) | <0.0001 |
| + | + | 23/14 | 6.9 (3.5–13.5) | 7.0 (6.4–7.6) | <0.0001 |
| Interaction term | 2.4 (1.1–5.1) | 2.4 (1.3–5.2) | 0.02 | ||
| AP | 0.7 (0.2–0.9) | 0.7 (0.2–0.8) | |||
| RERI | 4.5 (1.1–11.2) | 4.5 (1.1–11.2) | |||
| SI | 4.3 (1.8–10.4) | 4.2 (1.7–10.2) | |||
| IM after age 10 | |||||
| − | − | 688/2748 | 1.0 (–) | 1.0 (–) | |
| + | − | 66/163 | 1.6 (1.2–2.2) | 1.6 (1.2–2.2) | 0.0002 |
| − | + | 103/213 | 2.0 (1.5–2.6) | 2.0 (1.6–2.6) | <0.0001 |
| + | + | 18/6 | 13.1 (5.1–33.2) | 13.2 (5.2–33.6) | <0.0001 |
| Interaction term | 4.0 (1.5–11.0) | 4.0 (1.5–11.0) | 0.007 | ||
| AP | 0.8 (0.4–0.9) | 0.8 (0.4–0.9) | |||
| RERI | 10.4 (2.5–30.5) | 10.6 (2.5–31.0) | |||
| SI | 7.4 (2.5–22.1) | 7.4 (2.5–22.1) |
aNumber of exposed cases and controls; badjusted for matching variables, origin and smoking habits; cadjusted for matching variables, origin, smoking habits and HLA-A*02.