Association between serum gamma-glutamyltransferase and C-reactive protein

A series of epidemiological studies have suggested serum gamma glutamyltransferase (GGT) within its normal range might be an early marker of oxidative stress. Oxidative stress appears to be a key component of many reactions associated with chronic inflammation. Therefore, we examined the cross-sectional association between deciles of serum GGT and concentrations of serum C-reactive protein (CRP), a marker of chronic inflammation, among 12,110 adult participants in the third U.S. National Health and Nutrition Examination Survey. After adjustment for race, sex, age, cigarette smoking, alcohol intake, and body mass index (BMI), serum concentration of GGT across all deciles was positively associated with serum concentrations of CRP (P for trend < 0.01). For example, adjusted relative risks of serum CRP greater than or equal to 3.0 mg/L by deciles of serum GGT were 1.0, 1.23, 1.40, 1.59, 1.62, 1.61, 2.17, 2.38, 2.45, and 3.41 (P for trend < 0.01). This association was consistently observed among all subgroups; Non-Hispanic White, Non-Hispanic Black, Mexican American, men, women, non-drinkers, drinkers, non-smokers, ex-smokers, current smokers, BMI < 25, BMI 25-29.9, and BMI greater than or equal to 30. The strong association of serum GGT and CRP suggest that further studies on cellular and/or serum GGT might help to elucidate the association between oxidative stress and inflammation. (C) 2004 Elsevier Ireland Ltd. All rights reserved.