No studies explored the gene-gene, gene-environment interactions between CHRNA7 polymorphism, apolipoprotein E (APOE) ε4 status and smoking on dementia risk.
ACT or CHRNA7 genotypes were not associated with MCI but both appear to modify the risk of progression to dementia in opposing manners: ACT polymorphism increasing the risk to evolve to AD before 20 months (HR=2.03; 95% CI: 1-4.6; p=0.06) and CHRNA7 polymorphism protecting from evolution to dementia.