A Systematic Review of Meta-Analyses that Evaluate Risk Factors for Dementia to Evaluate the Quantity, Quality, and Global Representativeness of Evidence

Abstract

Background: The translation of evidence on dementia risk factors into clinical advice requires careful evaluation of the methodology and scope of data from which risk estimates are obtained. Objective: To evaluate the quantity, quality, and representativeness of evidence, we conducted a review of reviews of risk factors for Alzheimer’s disease (AD), Vascular dementia (VaD), and Any Dementia. Methods: PubMed, Cochrane library, and the Global Index Medicus were searched to identify meta-analyses of observational studies of risk factors for AD, VaD, and Any Dementia. PROSPERO CRD42017053920. Results: Meta-analysis data were available for 34 risk factors for AD, 26 risk factors for Any Dementia and eight for VaD. Quality of evidence varied greatly in terms of the number of contributing studies, whether data on midlife exposure was available, and consistency of measures. The most evidence was available for cardiovascular risk factors. The most geographically representative evidence (five of six global regions) was available for alcohol, physical activity, diabetes, high midlife BMI, antihypertensives, and motor function. Evidence from Australia/Oceana or Africa was limited. With the exception of diabetes, meta-analysis data were unavailable from Latin America/Caribbean. Midlife specific data were only available for cholesterol and arthritis. Conclusion: There is a lack of midlife specific data, limited data on VaD, and a lack of geographical representation for many risk factors for dementia. The quality, quantity, and representativeness of evidence needs to be considered before recommendations are made about the relevance of risk factors in mid- or late-life or for dementia subtypes.

Role of Alcohol Drinking in Alzheimer’s Disease, Parkinson’s Disease, and Amyotrophic Lateral Sclerosis

“…A 2019 meta-analysis reviewed 91 articles involving 36 risk factors for AD [45]. The authors concluded that significant associations with AD decreased risk were found for alcohol consumption (any or light/moderate versus abstinence) from risk ratio (RR) = 0.43 (95% CI = 0.17-0.69) [46] to 0.72 (95% CI = 0.61-0.86) [47].…”

Future Directions for Dementia Risk Reduction and Prevention Research: An International Research Network on Dementia Prevention Consensus

“…Early work by committee members [13,14] and other recent reports such as the Lancet Commission [15] concluded that childhood education, exercise, maintaining social engagement, reducing smoking, and management of hearing loss, depression, diabetes, and obesity across the life course are key protective factors which collectively have potential to delay or prevent a third of dementia cases. The weight of evidence at present suggests that latelife cognitive decline and dementia are amenable to modification by treatment of vascular risk Evidence was collated from a number of large-scale reviews [17][18][19][20] and influenced by [13-16, 46, 47]. factors, increase in physical, mental, and social activity, and avoiding environmental hazards [16,17].…”

Prävention von Schlaganfall und Demenz in der Hausarztpraxis: Evaluation des Projektes INVADE

“…Dazu zählen vor allem Hypertonie, körperliche Inaktivität, Fehlernährung, Übergewicht, Depression, Rauchen, Alkoholmissbrauch und Diabetes mellitus. Dieselben Risikofaktoren tragen nach gegenwärtiger Kenntnis auch zur Entstehung von Demenzen bei [7][8][9][10][11]. Ihre Elimination ließe nach einigen Modellrechnungen eine Reduktion der demenziellen Neuerkrankungen um etwa 30 % erwarten [12,13].…”