In men, compared to participants with lowest tertile of vitamin D, those with the highest tertile of vitamin D had a lower risk of dementia in both APOE e4 non-carries (HR = 0.65, 95% CI 0.56–0.75) and APOE e4 carries (HR = 0.80, 95% CI 0.69–0.92) (Additional file 1: Table S6). This evidence concerns the gene APOE and dementia.