Serum Gamma-Glutamyl Transferase Levels are Associated with Metabolic Syndrome in Community-Dwelling Individuals

Aim: Serum gamma-glutamyl transferase (GGT) activity changes in response to oxidative stress. Metabolic syndrome (MetS) is associated with an increased risk of major cardiovascular events. Few data are available on the association between serum GGT and the prevalence of MetS among community-dwelling individuals in Japan. Methods: We recruited 793 men (mean age, 60 +/- 14 years), and 1,073 women (62 +/- 12 years), free from any history relating to cardiovascular disease during their annual health examination, from a single community. We performed a cross-sectional study to examine whether serum GGT was associated with MetS. Results: The levels of most confounding characteristics varied with increasing GGT activity After adjustment for age, smoking status, drinking status, low-density lipoprotein cholesterol, uric acid, estimated glomerular filtration rate and alanine aminotransferase, the odds ratios (95% confidence interval) for MetS increased across serum GGT tertiles (1, 2.23 (1.22-4.07), and 2.32 (1.18-4.56) in men; and 1, 1.43 (0.81-2.51), and 2.64 (1.50-4.64) in women). After additional adjustment for insulin resistance markers (immuno-reactive insulin or homoeostasis model assessment of insulin resistance index), the association was attenuated and the linear relation no longer significant in both genders. Furthermore, serum GGT was significantly associated with the presence of individual components of MetS in both genders, except for dyslipidemia in men and hypertension in women. Conclusions: These results suggested that higher serum GGT was significantly associated with MetS and its components in the general population. This association was related with insulin resistance but was independent of other confounding factors.