APOE and sleep apnea syndrome: In subsequent analyses, APOE-e4, but not sleep apnea or their interaction was associated with a higher likelihood of having mild cognitive impairment or dementia (χ2(5) = 44.183, p < 0.001), with being an APOE-e4 carrier, regardless of the number of alleles being more associated than not being a carrier (p < 0.001; see Table 3 for results of the fully adjusted models).