Primary outcome: General cognitive function
cognitive abnormality
The primary outcome measure was general cognitive function determined through the MoCA. The MoCA measures visual-spatial/executive function, naming ability, memory, attention, abstraction, and verbal ability. The total score is 30; a high score represents a better cognitive function. A score of less than 26 is regarded as a cognitive abnormality. If the length of education was less than 12 years, one point was added to the score [