Frequency and correlates of mild cognitive impairment and dementia among the oldest old - Evidence from the representative "Survey on quality of life and subjective well-being of the very old in North Rhine-Westphalia (NRW80+)"

OBJECTIVES: Since there is limited knowledge with regard to the frequency and correlates of mild cognitive impairment and dementia among the oldest old based on large representative data (including institutionalized individuals), our objective was to fill this research gap.

METHODS: For our study, data came from the representative "Survey on quality of life and subjective well-being of the very old in North Rhine-Westphalia (NRW80+)". This study included community-dwelling and institutionalized individuals aged 80 years and over (n = 1,173, mean age: 86 years) residing in the most populous state of Germany (North Rhine-Westphalia). The DemTect was used to quantify cognitive impairment (i.e., probable mild cognitive impairment and probable dementia).

RESULTS: Overall, 73.1% of the individuals were not cognitively impaired, 17.0% of the individuals had probable mild cognitive impairment and 9.9% of the individuals had probable dementia. Compared to individuals without cognitive impairment, individuals with probable mild cognitive impairment were more likely to be male, live in an institutionalized setting, have a lower educational level, have a smaller network size, and have lower functional abilities. Moreover, compared to individuals without cognitive impairment, individuals with probable dementia were more likely to be older, live in an institutionalized setting, have a lower educational level, have a smaller network size, not be multimorbid, and have lower functional abilities.

CONCLUSIONS: Our study identified several sociodemographic and health-related factors which are associated with probable mild cognitive impairment and probable dementia among the oldest old. This knowledge may help to address individuals at risk for mild cognitive impairment and dementia.