For example, in a longitudinal study of primary care patients aged 75 years or older, those with both the APOE-ε4 allele and low physical activity (defined as less than one physical activity per week) had a higher conversion rate (21.5%) to dementia and Alzheimer’s disease, as well as a higher relative risk (relative risk: 3.02, 95% CI: 2.07, 4.42) of dementia and Alzheimer’s disease, compared to those who had only one of the risk factors present [27]. Here, APOE is linked to early-onset autosomal dominant Alzheimer disease.