Smoking enhanced the association between high anti-EBNA titers and increased multiple sclerosis risk, with a stronger risk among ever smokers (OR 3.9) than never smokers (OR 1.8; p=0.001).
Case-Control (n=1,307)
Yes
Does smoking modify the association between anti-EBNA antibody titers, HLA-DR15, and multiple sclerosis risk?
Smoking appears to enhance the association between high anti-EBNA titers and increased multiple sclerosis risk, whereas the association with HLA-DR15 is independent of smoking.
Effect estimate: OR 3.9 (95% CI 2.7-5.7)
p-value: p=0.001
OBJECTIVE: To examine the interplay between smoking, serum antibody titers to the Epstein-Barr virus nuclear antigens (anti-EBNA), and HLA-DR15 on multiple sclerosis (MS) risk. METHODS: Individual and pooled analyses were conducted among 442 cases and 865 controls from 3 MS case-control studies-a nested case-control study in the Nurses' Health Study/Nurses' Health Study II, the Tasmanian MS Study, and a Swedish MS Study. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% CIs for the association between smoking, anti-EBNA titers, HLA-DR15, and MS risk. Study estimates were pooled using inverse variance weights to determine a combined effect and p value. RESULTS: Among MS cases, anti-EBNA titers were significantly higher in ever smokers compared to never smokers. The increased risk of MS associated with high anti-EBNA Ab titers was stronger among ever smokers (OR = 3.9, 95% CI = 2.7-5.7) compared to never smokers (OR = 1.8, 95% CI = 1.4-2.3; p for interaction = 0.001). The increased risk of MS associated with a history of smoking was no longer evident after adjustment for anti-EBNA Ab titers. No modification or confounding by HLA-DR15 was observed. The increased risk of MS associated with ever smoking was only observed among those who had high anti-EBNA titers (OR = 1.7, 95% CI = 1.1-2.6). CONCLUSIONS: Smoking appears to enhance the association between high anti-EBNA titer and increased multiple sclerosis (MS) risk. The association between HLA-DR15 and MS risk is independent of smoking. Further work is necessary to elucidate possible biologic mechanisms to explain this finding.
Simon et al. (Wed,) conducted a case-control in Multiple sclerosis (n=1,307). Smoking and high anti-EBNA titers vs. Never smoking and low anti-EBNA titers was evaluated on Multiple sclerosis risk (OR 3.9, 95% CI 2.7-5.7, p=0.001). Smoking enhanced the association between high anti-EBNA titers and increased multiple sclerosis risk, with a stronger risk among ever smokers (OR 3.9) than never smokers (OR 1.8; p=0.001).