APOE and dementia: For men, there was significant additive interaction (RERI 3.81, 95% CI 0.67–6.96; AP 0.40, 95% CI 0.14–0.66; S 1.81, 95% CI 1.09–3.01) between one APOE-ε4 allele carriers and former smoking on dementia risk while non-significant multiplicative interaction was identified (HR 1.49; 95% CI 0.92–2.41) (Supplementary Table S2).