Still, people with the same number of years of formal education may vary greatly in their cognitive abilities.95 Many studies have suggested that ApoE ε4 carrier status modifies the relationship between PA and dementia.11–13 Our ApoE ε4 interaction analyses suggest no such modification for all-cause dementia, Alzheimer’s disease or vascular dementia. The gene discussed is APOE; the disease is early-onset autosomal dominant Alzheimer disease.