Interaction Between Genetic and Environmental Factors in Multiple Sclerosis?

Abstract

Genetic, as well as environmental factors, may represent risk fac- tors for multiple sclerosis. A question of particular interest is whether risk factors may work synergistically. The main findings in this study are that whereas two genetic risk factors and a history of smoking have highly significant main effects on the risk (P-value <0.001), there is not sufficient evidence to proclaim an interaction between any of these genetic factors and smoking at a 5% level of significance. How- ever, there is a significant interaction between gender and smoking. The interaction indicates that smoking among males contributes more to the risk of getting multiple sclerosis than smoking among females. Previous Epstein Barr virus infection is a significant risk factor when adjusting for smoking only. The data reveal a strong protective ef- fect of snuffing. Contrary to the estimate of the effect of Epstein Barr virus infection, the latter estimate is statistically significant also after inclusion of several adjustment variables.