Cognitive frailty typologies and subsequent dementia in a large representative sample of the English population

Background Cognitive Frailty (CF), the coexistence of mild cognitive impairment with physical frailty, may represent an intermediate state between functional vulnerability and preclinical dementia. Its potential reversibility makes it an important target for prevention. Distinguishing patterns of CF that are more and less likely to lead to dementia, and associated factors, is important for developing interventions. Methods Using data from the English Longitudinal Study of Ageing (Waves 4-9), we examined different typologies of CF based on specific cognitive impairments demonstrated. We compared longitudinal outcomes of incident dementia over 10 years for the different typologies. We also examined the impact of inequalities (Index of Multiple Deprivation (IMD) and household wealth), cognitive reserve (low education), and psychosocial factors (depression and loneliness) on the longitudinal models. Results CF groups with executive function (using verbal fluency) and/or processing speed impairment (Group 1) are distinguished from those with memory impairment only (Group 2) or impaired memory and executive function and/or processing speed (Group 3). Inequalities, cognitive reserve and psychosocial factors all show association with CF likelihood, but education (odds ratio (OR) of no qualifications compared to degree/higher education = 1.632 (Group 1) and 3.436 (Group 3)), IMD (OR 1.656 (Group 1 quintile 5), 2.083 (Group 3 quintile 4) compared to quintile 1) and loneliness (OR 1.208 (Group 1), 1.185 (Group 3)) are only associated with CF where executive function/processing speed are key characteristics. Longitudinally, only CF groupings with memory impairment (OR 2.024, Group 2; 2.733, Group 3) are predictive of dementia. Conclusions Distinguishing typologies of CF and associated risk factors is important for estimating future dementia risk, and for targeted design of interventions.