Midlife substances use risk factors and cognitive disorder in late life: A systematic review using meta-analysis

Abstract

Globally, geriatric cognitive disorder is one of the eminent and challenging events. There is a significant relationship between long-term substance use and CD. Thus, the main objective of the current study was to synthesize the probable evidence of retrospective studies on the impact of substance use in midlife on cognitive disorders in later life. A systematic review through meta-analysis was conducted to reveal the harmful effects of substance use on any type of CD. All the empirical studies that scrutinized the association between smoking or alcohol consumption in midlife and cognitive disorder in later life were included, adjusted for other covariates based on the required inclusion and exclusion criteria of this study. Database searches were conducted using Google Scholar, Web of Science, SocINDEX, PsycINFO, ProQuest, PubMed, Scopus, and APA PsycINFO. A total of 9 studies were considered to perform the meta-analysis. Almost all the studies (8) examined that midlife substance user were likely to have CD in their later life. Applying the random effect model, the average effect size was estimated as 1.31 [95 % CI: 0.37, 2.25], which indicates that participants who consume alcohol or smoke in midlife had 1.31 times more risk of having CD in their later life than substance abstainers in midlife. In the sub-group analysis between alcohol and smoking, we found that alcohol consumption [RR 1.76, 95 % CI: 0.54, 2.98] is more likely to induce cognitive disorder in late life than smoking [RR 0.75, 95 % CI: 0.02, 1.47]. The result of this systematic analysis suggests that the long-term effects of drinking or smoking are not immune to the brain. So, substance use reduction could be an appropriate population-wide intervention tactic.