Risk factors for vascular dementia: a review.

In recent years, interest in vascular causes of dementia has increased and it has been proposed that vascular dementia (VAD) may be more common than previously supposed. This may have important implications, because VAD at present may be more amenable to prevention and treatment than Alzheimer's disease (AD). Several vascular factors have been related to cognitive decline and dementia in the elderly, including stroke and white matter disease. However, while numerous case-control studies have been concerned with the risk factors for AD, studies on risk factors for VADs are rare. The problems inherent in the diagnostic criteria make it difficult to interpret the results from the few studies that have been performed. Generally, risk factors for multi-infarct dementia are supposed to be the same as those for stroke, and include hypertension, diabetes mellitus, advanced age, male sex, smoking and cardiac diseases. White matter dementia has mainly been related to hypertension. Recent research suggests that vascular factors may also be important in AD, especially in the late-onset type. In stroke patients, dementia has been associated with higher age, less formal education, cerebral atrophy, left-sided or bilateral infarcts, volume of macroscopic infarcts, bilateral symptoms, previous stroke and white matter lesions. The pathogenetic mechanism through which these factors cause dementia is still not clear. Furthermore, it is not known if risk factors for VAD differ from those found in stroke patients. There is now an urgent need for further research on risk factors for VAD and on factors related to dementia in subjects with cerebrovascular disorders.