Characteristics of the study groups at baseline in 2000, means ± SD, or N (%).

Educational level differences were compared using chi-square test for categorical variables and ANOVA analysis for continuous variables.Age, occupation, cigarette smoking, alcohol consumption, physical exercise, BMI, WC, RHR, BP, TC, TG, UA, and FPG were collected annually from 2000 to 2011.Family history of diabetes, marriage status, and work strength were collected annually from 2000 to 2003.Dietary intake and salt taste preference were collected in 2000 and 2003.