γ-Glutamyltransferase and Risk of Sudden Cardiac Death in Middle-Aged Finnish Men: A New Prospective Cohort Study

BACKGROUND: γ-Glutamyltransferase (GGT) has been linked to an increased risk of several cardiovascular outcomes; however, the relationship of GGT with sudden cardiac death (SCD) has not been investigated previously. We aimed to assess the association of GGT with risk of SCD.

METHODS AND RESULTS: Serum GGT activity was assessed at baseline in the Kuopio Ischemic Heart Disease prospective cohort of 1780 men, and 136 SCDs were recorded during 22 years of follow-up. Correction for within-person variability was made using data from repeated measurements taken several years apart. The regression dilution ratio of loge GGT adjusted for age was 0.68 (95% CI 0.61-0.74). Serum GGT was log-linearly associated with risk of SCD. The hazard ratio for SCD per 1 SD higher baseline loge GGT values (2-fold higher) was 1.30 (95% CI 1.10-1.54; P=0.002) after adjustment for several established risk factors and remained consistent with further adjustment for alcohol consumption, resting heart rate, lipids, and C-reactive protein (hazard ratio 1.26, 95% CI 1.05-1.50; P=0.014). The corresponding hazard ratios were 1.48 (95% CI 1.15-1.89; P=0.002) and 1.40 (95% CI 1.07-1.82; P=0.014) after correction for within-person variability. Hazard ratios remained unchanged after accounting for incident coronary events and did not vary importantly by levels or categories of prespecified conventional risk factors.

CONCLUSIONS: GGT is positively, log-linearly, and independently associated with future risk of SCD in the general male population. Further research is needed to replicate these findings.