Comparison of the Impact of Changes in Waist Circumference and Body Mass Index in Relation to Changes in Serum Gamma-Glutamyltransferase Levels

Abstract

Serum gamma-glutamyltransferase (GGT) levels, which are associated with insulin resistance, may predict the incidence of cardiovascular disease and mortality. Here, the relationship was analyzed between changes in obesity parameters and those in serum GGT over a one-year period. Data were analyzed from individuals who underwent general health screening two years running. Among 3086 individuals (1954 men, 1132 women), percent changes in both waist circumference (%dWC) and body mass index (BMI) (%dBMI) were significantly correlated with percent changes in GGT (%dGGT) in men (r=0.17 and r=0.31, respectively). On the other hand, in women, %dBMI, but not %dWC, had a significant association with %dGGT. When age, %dWC, %dBMI, smoking status, and alcohol intake were all included as independent variables, %dBMI, but not %dWC, showed a graded association with the highest %dGGT quartile in both genders. Furthermore, incorporation of %dWC as an additional independent variable to age, gender, and %dBMI did not show an incremental improvement in prediction for the highest %dGGT quartile (C statistic, 0.643 to 0.648; p= 0.380), suggesting that taking WC changes into account does not significantly improve the prediction of GGT changes when BMI has already been taken into consideration. Changes in BMI are dose-dependently associated with GGT changes in both genders; however, the additional consideration of changes in WC does not show a significant statistical improvement in the prediction of GGT changes.