BACKGROUND: Studies have demonstrated that the risk factors of vascular dementia following stroke are greatly different in region, race and other aspects.OBJECTIVE: To analyze the conditions and incidental risk factors of vascular dementia in patients with acute cerebral infarction from Chongqing City. DESIGN: Case analysis.SETTING: Department of Neurology, Daping Hospital, Third Military Medical University of Chinese PLA. PARTICIPANTS: Altogether 546 inpatients with acute ischemic stroke admitted to Department of Neurology, Daping Hospital, Third Military Medical University of Chinese PLA between May 1999 and December 2002 were involved in this study. The involved patients, including 295 males and 251 females, aged 55 - 94 years, dwelled in Chongqing over 5 years. They were admitted to hospital within 48 hours of attack of acute ischemic stroke, and survived for over 3 months. Informed consents were obtained from all the involved subjects.METHODS: ①Following the same standard, cognitive and social function evaluations were conducted by one physician on admission and 3 months after admission. Unified questionnaire, consisting of general characteristics, vascular risk factors, stroke characteristics, neurological physical sign, and other 28 factors of involved subjects, was used in all the patients. According to the investigation results, the patients were assigned into 2 groups: dementia group and non-dementia group. ②Ischemic stroke was diagnosed according to acute ischemic brain disorder＞24 hours and CT or MRI imageology.③Neurophysiological examination was conducted in all the patients at 7 to 10 days after stroke (score was two SD less than or equaled to normal level was considered as abnormal).④Diagnosis and statistics of dementia were carried out with Mini-Mental State Examination and The Diagnostic and Statistical Manual of Mental Disorders-IV (published by American Psychiatric Association) on admission and 3 months after admission. Neurologic deficit scoring was carried out with the National Institutes of Health Stroke Scale.⑤Chi-square test was used for categorical variable, and t test for quantitative variable between dementia group and non-dementia group. Dementia-related factors were performed multiple-factor Logistic regression model analysis. MAIN OUTCOME MEASURES: Incidence of dementia and dementia-related risk factors of patients. RESULTS: Altogether 546 patients with stroke were involved in this study, 403 of them participated in the final analysis, and 143 dropped out. A total of 342 were followed-up in the hospital and 61 at home. At 3 months after cerebral infarction, vascular dementia occurred in 87 (21.6%) of 403 patients. The main risk factors were age (OR 1.179; 95%CI 1.130 - 1.230), low education level (OR 1.806; 95%CI 1.024 - 3.186), daily alcohol drinking (OR 3.447; 95%CI 1.591 - 7.468), stroke history (OR 2.531; 95%CI 1.419-4.512), atrial fibrilation(OR 3.475; 95%CI 1.712 - 7.057), dysphonia (OR 5.873; 95%CI 2.620 - 13.163) and left carotid artery infarction (OR 1.975; 95%CI 1.152 - 3.388).CONCLUSION: The incidence of vascular dementia is determined by synthetic action of multiple risk factors. Dysphonia is the most important influencing factor.