Drinking coffee may reduce chances of developing Alzheimer’s disease: systematic literature review and meta-analysis

Coffee is a popular beverage, and it contains caffeine, a psychoactive substance. Consuming coffee may reduce the risk of developing Alzheimer’s disease (AD). However, the association between the reduced risk of developing AD and the consumption of coffee is controversial. Therefore, we conducted a systematic literature review and quantitative synthesis meta-analysis that included dose-response analysis on the relationship between the consumption of coffee and the risk of developing AD. Based on PRISMA guidelines, we analysed standard databases of journals published between January 1999 and May 2020. We included the two population-based cohort studies and one case-control study. All studies included looked at the association between consuming many cups of coffee, the amount of coffee consumed in milligrams per day and the risk of developing AD. The systematic literature review and meta-analysis had 1670 participants with follow-up years that ranged from 5 to 21. The consumption of moderate or 3-5 cups per day reduces the risk of developing AD. The pooled relative risk and 95% confidence interval of the 3 included studies were 0.63 (0.3, 1.54). Dose-response curve analysis appears to be U-shaped. The results of the forest plot showed that there is low heterogeneity between the studies. Plotting the funnel plot and the Galbraith plot demonstrated publication bias of the three included studies. More prospective and long-term studies have to be conducted in other countries to determine the exact risk of developing AD.