To illustrate the impact of social adversity on APOE allele effect, compared to people at intermediate genetic risk (ε3ε3) exposed to ≤ 1 unfavorable SDH, people at high genetic risk (ε4) in the lowest level of social adversity presented a lower risk of dementia than people at low genetic risk (ε2) in the highest level of social adversity (APOE-ε4 and low social adversity HR = 1.68, 95%CI = 1.37–2.06; APOE-ε2 and high social adversity HR = 3.26, 95%CI = 2.06–5.16) (Fig 1C, Table 2). The gene discussed is APOE; the disease is dementia.