In APOE4 carriers, the leading risk factors for all-cause dementia included low self-rated overall health (PAR (95% CI): 24.2% (11.2–28.7%)), low household income (22.3% (6–37.2%)), high multimorbidity risk score (19.5% (13.6–25.6%), long-term illness (15.7% (13.1–18.5%)), high neutrophil percentage (12.4% (5.1–19.2%)), high nitrogen dioxide air pollution 2010 (11 (3.8–17.8)), and high neutrophil count (10.3 (3–17.2)). This evidence concerns the gene APOE and dementia.