“…All diagnoses of VBI were made on the basis of the clinical symptoms and signs with a focus on the cardiovascular and neurological systems and/or supporting imaging studies (Doppler ultrasonography, magnetic resonance angiography or CT angiography) from outpatient departments of participating hospitals and clinics. 22 For each patient with VBI, four insured subjects were selected randomly from subjects without a diagnosis of VBI in the LHID, as the non-VBI group, and were frequency-matched by sex, age and comorbidities that are known to be dementia risk factors and that were established before the index date. Selection according to comorbidities was based on outpatient data of the following ICD codes: hypertension (ICD-9-CM codes 401–405), diabetes (ICD-9-CM code 250), ischaemic heart disease (ICD-9-CM codes 410–414), hyperlipidaemia (ICD-9-CM code 272), tobacco use disorder (ICD-9-CM code 305.1), alcoholism (ICD-9-CM codes 291, 303.9, 334.4, 980.0), obesity (ICD-9-CM codes 278, 649.1, 783.1), atrial fibrillation (ICD-9-CM code 427.3), Parkinson’s disease (ICD-9-CM code 332.0), cerebral vascular accident (ICD-9-CM codes 430–432, 433–437), major depression (ICD-9-CM code 296), chronic kidney disease (ICD-9-CM code 585) and carotid artery insufficiency (ICD-9-CM code 433.1, 435.8).…”