129 Risk of dementia related to APOE ε4 and a polygenic risk score Supplementary Table 3. Assocation between PRS and APOE ε4 and risk of clinical progression PRS APOE ε4 N HR (95% CI) p-value HR (95% CI) p-value Non-dementia 450 All-type dementia 41 0.9 (0.7-1.3) 7.1x10-1 2.0 (1.3-3.3) 3.5x10-3* AD dementia 25 1.5 (0.9-2.5) 1.3x10-1 2.9 (1.5-5.6) 1.5x10-3* Other dementia 16 0.5 (0.3-0.9) 2.0x10-2* 1.2 (0.5-2.8) 7.1x10-1 Values are obtained by Cox proportional hazard models, adjusted for age, sex, population substructure and MMSE. The model included both APOE ε4 allele and normalized PRS as predictors. Outcome: clinical progression to dementia. The HR associated with the PRS reflects the difference per one standard deviation increase in the PRS. APOE ε4 is per allele. * p-value <0.05. PRS = polygenic risk score; HR = hazard ratio; CI = confidence interval; AD = Alzheimer’s disease. 5