Fig. 1

Flow chart of the sample screening process. ^a The time points covered by this dataset contain the following years: 1998, 2000, 2002, 2005, 2008, 2011, 2014 and 2018. ^b The number includes individuals from the first baseline survey in 1998 and new participants added in follow-up surveys. ^c Variables for cognition, alcohol consumption, diet, and activity were included (details were shown in Additional file 1). Among them, individuals with cognitive-related MMSE scores exceeding the range of − 3 < MMSE z-score < 3 would be excluded (after adjustment for gender and age). ^d Age was based on their records at the time of the baseline survey