Each patient was followed up to assess the risk of dementia or protective factors: the demographic characteristics of age and sex; the comorbidities of diabetes, hypertension, dyslipidemia, cerebrovascular diseases, parkinsonism, epilepsy, substance- and alcohol-use disorders, mood disorder, anxiety disorder, psychotic disorder, and sleep disorder; urbanization level; monthly income; and statin, metformin, aspirin, and angiotensin-converting enzyme inhibitor (ACEI) use. This evidence concerns the gene ACE and diabetes mellitus.