STH and Alzheimer disease: After a careful review, 19 case–control studies from 17 articles with 4387 cases and 3972 controls were included in our meta‐analysis to determine the association between STH Q7R polymorphism and AD 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 21, 22, 23, 24 (Table 1).