Lack of association between serum gamma-glutamyltransferase and carotid atherosclerosis: The Namwon study

•No significant association of GGT concentration with carotid IMT was found in this large cross-sectional study.•Our study also suggests that serum GGT is not associated with carotid plaques.•Further longitudinal studies are needed to confirm our findings and evaluate the causal relationship, if any, between GGT and carotid atherosclerosis.

Objectives: There is little evidence for an association between gamma-glutamyltransferase (GGT) and carotid atherosclerosis, an independent predictor of cardiovascular disease. We examined the association between serum GGT and carotid atherosclerotic parameters, including carotid intima-media thickness (IMT) and plaques, in a large general population. Methods: The study population consisted of community-dwelling adults who participated in the baseline survey of the Namwon Study. A total of 9120 subjects aged 45-74 years were included in the analyses. High-resolution B-mode ultrasound was used to measure carotid IMT and to evaluate the presence of carotid plaques. A mean carotid IMT of ≥1.0 mm was classified as 'high carotid IMT'. Results: Serum GGT levels were classified into quartiles. In a fully adjusted model, we found no linear trend between GGT quartile and mean carotid IMT (P for trend = 0.167). Compared with the first quartile (the reference category), the odds ratios (ORs) and 95% confidence intervals (CIs) for high carotid IMT were 0.89 (0.68-1.16), 1.10 (0.84-1.43), and 0.97 (0.71-1.33) for the second, third, and fourth quartiles (P for trend = 0.754), respectively. The ORs (95% CIs) for carotid plaques were 0.89 (0.77-1.02), 0.95 (0.82-1.10), and 0.94 (0.79-1.11) for the second, third, and fourth quartiles, respectively, in the fully adjusted model (P for trend = 0.644). Conclusions: No significant association of GGT concentration with carotid IMT or plaques was found in this large cross-sectional study. Further longitudinal studies are needed to confirm our findings.