Alzheimer's disease (AD) is the most common type of dementia, Other types of dementia include vascular (VaD) and mixed forms, like AD with VaD, other mixed forms of dementia or dementia of unknown etiology (DUE). Research has focused on factors that may increase risk of developing dementia, with less understood about disease course. Factors associated with risk for developing dementia onset include age, female sex, family history of dementia, genetics (e.g. having the ε4 allele of the Apolipoprotein E or APOE gene), and various health conditions. This project used previously collected data from the Cache County Study on Memory and Aging (CCSMA) and the ancillary study, the Cache County Dementia Progression Study (DPS).
This study found that among different dementia types, there were modifiable and non-modifiable risk factors associated with type. General health status was among the most important factors associated dementia type and with severity of cognitive and functional impairment. Specific health conditions associated with increased risk for VaD included cardiovascular and cerebrovascular issues. Among males, diagnoses of AD with Other dementia or non-AD dementia alone, showed more rapid rate of functional decline, compared to females. Functionally, those diagnosed with VaD, AD with another form of dementia, or non-AD dementia alone, experienced worse functioning over time. Those with AD with another form of dementia, AD with VaD, and those with Other dementia, experienced poorer overall functioning in ADLs than those with AD alone. Lower BMI was associated with a higher risk for mortality, while those with higher BMI displayed longer survival. Poor health status and low BMI were strong predictors of mortality. Being diagnosed with AD with Other dementia, and non-AD dementia alone, followed by VaD alone had the greatest morality risk compared to having AD alone.
These results offer greater information on factors that influence dementia type and course, while providing possible avenues for intervention (e.g. managing specific health conditions). The identification of factors that influence mortality may inform healthcare providers' of duration of dementia and mortality.