A cross-sectional analysis of alcohol consumption, sex, and the odds of Alzheimer's disease and other dementias in the community-dwelling Canadian population

Background: The prevalence of Alzheimer’s disease (AD) and other dementias is perpetually increasing in Canada and worldwide with the aging baby boomer population. It is, therefore, important to identify risk factors for these major neurocognitive disorders, such as alcohol consumption, to mitigate the future burden on caregivers and the economy. The purpose of this study was to replicate previous research regarding the dose-response relationship between alcohol consumption and the odds of currently having AD or another dementia. The possibility of a sex effect moderating this relationship was also explored. Participants: Data were obtained for respondents to the combined 2015/16 cycles of the Canadian Community Health Survey who were aged 41 years or older at the time of the survey’s conduction (nweighted = 16,715,618). Methods: Logistic regression was used to crossectionally assess the relationship between various time- and frequency-related alcohol consumption exposures to outcome dementia status, while controlling for a number of demographic and risk factor variables. Results: A sex effect was identified for drinking at an average frequency of four to six times per week over the past year (p = 0.019, 95% CI: 0.03, 0.73) where women (ORw = 0.13) were more protected against currently having AD or dementia than men (ORm = 0.89) when compared to alcohol abstainers. Binge drinking two to three times per month (OR = 0.19, p = 0.015, 95% CI: 0.05, 0.73) and more than once per week over the past year (OR = 0.16, p = 0.007, 95% CI: 0.04, 0.61) significantly lessened the odds of currently having AD or dementia when compared against alcohol abstainers. A sex effect was present for those who were classified as very heavy drinkers (♂: 6+ drinks/day, ♀: 4+ drinks/day) over the past week (p = 0.018, 95% CI: 1.14, 39.41) where alcohol was protective against currently having AD or dementia in men (ORm = 0.29) and alcohol was a risk factor for currently having AD or dementia in women (ORw = 2.15) when both were referenced with alcohol abstainers. Conclusions: With the exception of very heavy drinker women, drinking alcohol was associated with a reduced likelihood of currently having AD or dementia and sex effects were identified for drinking at a moderate frequency over the past year and very heavy drinkers. However, these results should be interpreted with caution due to the possibility of selection, sparse data, and abstainer biases as well as misclassification error. The primary implication of this research is to inform future studies that a more thorough exploration of a sex effect influencing the relationship between alcohol consumption and having AD or dementia is warranted.