To determine the prevalence and types of cognitive impairment in a sample of non-demented aged 90 and older (the oldest-old) and to examine the relationships between cognitive impairment and cardiovascular risk factors.
420 non-demented participants from The 90+ Study, a study of aging and dementia in the oldest-old. Participants were categorized into four non-overlapping groups: normal cognition, amnestic mild cognitive impairment (aMCI), non-amnestic MCI (naMCI), and other cognitive impairment (OCI). History of cardiovascular risk factors was assessed through self-report.
The overall prevalence of cognitive impairment in non-demented was 34.0% (95%CI: 29.5–38.5). The prevalence of OCI was highest (17.4%; 95%CI: 13.9–21.4) followed by aMCI (8.3%; 95%CI: 5.9–11.4) and naMCI (8.3%; 95%CI: 5.9–11.4). Normal cognition was present in 66.0% (95%CI: 61.2–70.5) of participants. History of hypertension and stroke were the only risk factors that varied between the groups, occurring more frequently in participants with naMCI (χ2=3.82; p<0.05) and OCI (χ2=5.51; p<0.05).
This study found a high prevalence of cognitive impairment in a sample of non-demented oldest-old. We did not find a strong relationship between cardiovascular risk factors and the cognitive impairment groups other than between hypertension and naMCI and stroke and OCI. Future studies comparing the incidence of dementia in these groups will ultimately determine their predictive utility in the oldest-old.