Assessing interactions between HLA-DRB1*15 and infectious mononucleosis on the risk of multiple sclerosis(20/02/13)Summary: This study from the UK looked at gene-environment interactions in MS.
The researchers looked at the interaction between HLA-DRB1*15 (DRB1-15) and history of infectious mononucleosis (IM). They found that individuals exposed to both factors were at an increased risk of disease. Both DRB1-15 and IM status were independent predictors of disease, while there interaction term was not, but interaction on an additive scale was evident.
Based on this, if the additive model is appropriate, the DRB1-15 and IM may be part of the causal process leading to MS. This study demonstrates the importance of reporting gene-environment interactions on both a multiplicative and additive scale.
Abstract
Gene-environment interactions may shed light on the mechanisms underlying multiple sclerosis (MS). We pooled data from two case-control studies on incident demyelination and used different methods to assess interaction between HLA-DRB1*15 (DRB1-15) and history of infectious mononucleosis (IM). Individuals exposed to both factors were at substantially increased risk of disease (OR=7.32, 95% CI=4.92-10.90).
In logistic regression models, DRB1-15 and IM status were independent predictors of disease while their interaction term was not (DRB1-15*IM: OR=1.35, 95% CI=0.79-2.23). However, interaction on an additive scale was evident (Synergy index=2.09, 95% CI=1.59-2.59; excess risk due to interaction=3.30, 95%CI=0.47-6.12; attributable proportion due to interaction=45%, 95% CI=22-68%).
This suggests, if the additive model is appropriate, the DRB1-15 and IM may be involved in the same causal process leading to MS and highlights the benefit of reporting gene-environment interactions on both a multiplicative and additive scale.
Authors: Disanto G, Hall C, Lucas R
Source: Mult Scler. 2013 Feb 14 & Pubmed PMID: 23413297 (20/02/13)