Relationship between serum amylase and BMI according to age groups (open circle: younger subjects aged 54 years old or less, closed circle: older subjects aged 55 years old or more). Statistical difference was examined by two-way ANOVA and P value was significant at P < 0.0001. The numbers of subjects in six BMI groups (- 19.0, 19.1-21.0, 21.1-23.0, 23.1-25.0, 25.1-27.0, and 27.1-kg/m2) are 157, 371, 638, 566, 330, and 282, respectively. BMI: body mass index. Bars express standard errors.