Alcohol consumption in relation to cognitive dysfunction and dementia: A systematic review and dose-response meta-analysis of prospective cohort studies.

BACKGROUND

Alcohol use is associated with a wide spectrum of neurological disorders, including cognitive dysfunction and dementia. Likewise, the high prevalence of cognitive dysfunction and dementia specifies the urgent need to identify modifiable risk factors. Because findings on alcohol and cognitive dysfunction and dementia have been inconsistent, the present dose-response meta-analysis of prospective cohort studies was conducted to evaluate the available evidence.

METHOD AND MATERIALS

A systematic search was conducted on PubMed/MEDLINE, Scopus, Embase, and PsychInfo databases and Google Scholar up to April, 2023. In the dose-response meta-analysis, a restricted cubic spline regression model was conducted to evaluate a possible non-linear relation between alcohol intake and the outcomes. Random-effects model was used to perform the meta-analysis and evaluate heterogeneity. Egger's test and a funnel plot were used to assess small study effects. Subgroup analyses were carried out to explore possible sources of heterogeneity.

RESULTS

Seventeen eligible studies comprising 80,680 total persons with 4,929 cases for dementia and 13,530 total persons with 1579 cases for cognitive dysfunction were included for dose-response analysis. When compared to the reference group of 0g/day of alcohol intake, the dose-response meta-analysis revealed a significant non-linear (J-shaped) association between alcohol intake and the risk of each of cognitive dysfunction, (lower dose range: 1-30.5g/day, RR: 0.97; 95% CI 0.95-0.99; higher dose range: >30.5g/day, RR: 1.07; 95% CI 1.01-1.15) and dementia (lower dose range: 1-17.5g/day, RR: 0.92; 95% CI 0.88-0.96, higher dose range: >17.5g/day, RR: 1.23; 95% CI 1.09-1.35). The lowest risk was achieved at approximately 30g/day of alcohol for cognitive dysfunction and 15g/day for dementia. The J-shape association remained with subgroups defined by age (≤65; >65 years) or study duration (<10; ≥10 years) for dementia, and within age >65 and duration <10 years for cognitive dysfunction.

CONCLUSION

We observed a J-shape association between alcohol consumption and both cognitive dysfunction and dementia, with light-to-moderate alcohol intake being associated with a reduced risk in adults. Further studies are needed to clarify more specifically the association between alcohol consumption and six domains of cognitive dysfunction based on diagnostic and statistical manual of mental disorders (DSM) criteria.

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Déclaration de conflit d'intérêts

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.