Modifiable dementia risk and protective factors in persons with subjective cognitive decline or mild cognitive impairment: a systematic literature review and Delphi study

Abstract

AbstractBackgroundMany studies showed that addressing modifiable risk factors has an impact on dementia prevalence and incidence. Most studies have focussed on universal prevention, irrespective of individual risk stage, with risk factors for dementia mainly identified in the general population. Less is known about the most important target risk factors in persons with subjective cognitive decline (SCD) or mild cognitive impairment (MCI), and hence, whether they have a similar potential for risk reduction as the general population. Therefore, this study aims to identify modifiable risk and protective factors for cognitive deterioration and dementia in persons with SCD or MCI.MethodWe use a mixed‐methods approach combining findings from a systematic literature review and an online Delphi study. Four electronic databases (PubMed, EMBASE, PsycINFO, Web of Science) were searched to review relevant literature. A broad search term was developed in consultation with an experienced librarian and consisted of terms linked to SCD, MCI, dementia, modifiable risk factors and disease progression. Observational studies with at least 50 participants and 1 year of follow‐up were considered for inclusion. Twenty international dementia prevention experts were invited to participate in the online Delphi study. In two rounds, experts were asked to spontaneously name, rank and weigh modifiable risk and protective factors in order of importance for the target population.ResultOur search yielded 19,128 abstracts in total. After removal of duplicates, 9,862 abstracts were considered for inclusion and 203 full‐texts were read, of which 69 were included in our review. Several risk and protective factors were encountered including somatic, lifestyle and neuropsychiatric factors, and they are further scrutinized. Eighteen experts named 31 risk and protective factors in the first Delphi study round, of which physical activity, social isolation and hypertension were ranked highest. Results of round two are being collected.ConclusionFindings from the current study will result in an inventory of relevant modifiable risk and protective factors linked with clinical progression in persons with SCD or MCI. Results will serve as the basis for the development and testing of an online dementia risk reduction tool for use in clinical populations with SCD and MCI.