Wine Information Council

IMPORTANCE: The impact of serial changes in alcohol consumption on dementia risk has rarely been investigated to date. OBJECTIVE: To investigate the association of comprehensive patterns of changes in alcohol consumption with the incidence of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VaD). DESIGN, SETTING, AND PARTICIPANTS: This is a retrospective cohort study.

Data were obtained from the Korean National Health Insurance Service database. Adults aged 40 years and older underwent 2 health examinations in 2009 and 2011. The cohort was assessed until December 31, 2018, and statistical analysis was performed in December 2021. EXPOSURES: Alcohol consumption level was categorized into none (0 g per day), mild (/=30 g per day) drinking. On the basis of changes in alcohol consumption level from 2009 to 2011, participants were categorized into the following groups: nondrinker, quitter, reducer, sustainer, and increaser.

MAIN OUTCOMES AND MEASURES: The primary outcome was newly diagnosed AD, VaD, or other dementia.

RESULTS: Among 3 933 382 participants (mean [SD] age, 55.0 [9.6] years; 2 037 948 men [51.8%]), during a mean (SD) follow-up of 6.3 (0.7) years, there were 100 282 cases of all-cause dementia, 79 982 cases of AD, and 11 085 cases of VaD. Compared with sustained nondrinking, sustained mild (adjusted hazard ratio [aHR], 0.79; 95% CI, 0.77-0.81) and moderate (aHR, 0.83; 95% CI, 0.79-0.88) drinking were associated with a decreased risk of all-cause dementia, whereas sustained heavy drinking was associated with an increased risk of all-cause dementia (aHR, 1.08; 95% CI, 1.03-1.12).

Compared with sustained levels of drinking, reducing alcohol consumption from a heavy to a moderate level (aHR, 0.92; 95% CI, 0.86-0.99) and the initiation of mild alcohol consumption (aHR, 0.93; 95% CI, 0.90-0.96) were associated with a decreased risk of all-cause dementia.

Increasers and quitters exhibited an increased risk of all-cause dementia compared with sustainers. The trends in AD and VaD remained consistent. CONCLUSIONS AND RELEVANCE: In this cohort study of a Korean population, decreased risk of dementia was associated with maintaining mild to moderate alcohol consumption, reducing alcohol consumption from a heavy to a moderate level, and the initiation of mild alcohol consumption, suggesting that the threshold of alcohol consumption for dementia risk reduction is low.

AIM: This study aimed to investigate the association between alcohol consumption and the risk of Alzheimer's disease (AD). METHODS: PubMed and Web of Science databases were systematically searched as of 1 September 2019. Relative risk and 95% CI were used to evaluate the association between alcohol consumption and AD risk. Subgroup analyses based on the type of alcohol, ethnicity, study design and sex were carried out. An alcohol dose-response meta-analysis was carried out. RESULTS: A total of 13 studies were included in the quantitative synthesis, and six were used in the dose-response meta-analysis. Compared with non-drinkers, individuals who drank had a lower risk of AD (relative risk 0.68, 95% CI 0.53-0.87; I(2) = 87.9%, P < 0.001). In subgroup analyses, drinking wine was found to reduce the occurrence of AD (relative risk 0.71, 95% CI 0.51-0.96). When stratified by ethnicity, sex and study design, no association was seen between AD risk and alcohol use. There was an overall non-linear, but not significant, association between alcohol intake dose and AD risk. A significant non-linear association was observed between excess AD risk and alcohol intake dose in men (overall P = 0.023; P for non-linearity = 0.025) starting from 14.8 drinks per week. Women's alcohol intake dose <16.9 drinks per week showed a significant non-linear association with decreased AD risk (overall P = 0.002; P for non-linearity = 0.019). CONCLUSIONS: Drinking alcohol could reduce the risk of AD. Alcohol dose had a non-linear, but non-significant, relationship with the development of AD. The amount of alcohol consumption showed significant sex-specific effects on AD. Geriatr Gerontol Int 2022; 22: 278-285.