Elevation of liver enzymes within the normal limits and metabolic syndrome: reply

Abstract

We appreciate the thoughtful comments by Kawada. 1 The purpose of our study 2 was to detect the association between liver enzymes and metabolic syndrome (MS) and, further, to determine the optimal cutoff values for liver enzymes in MS in 1503 individuals from a physical examination centre. We concluded that both aminotransferase (ALT) and c-glutamyl transpeptidase (GGT) were significantly associated with MS in our study. Although we performed a sex-stratified logistic regression analysis adjusted for age, body mass index (BMI), smoking and alcohol consumption, Kawada notes that we did not use liver enzymes simultaneously in our analysis and also failed to adjust for some other related factors, such as serum uric acid and insulin resistance (HOMA-IR). Statistically, we agree that this approach would better reveal the independent risk factors associated with MS by using all possible related factors simultaneously in one regression model. As Kawada has recommended, we further conducted logistic regression analysis (Wald method) to predict MS by BMI, sex, the log-transformed values of age, ALT, AST, GGT and lifestyle factors (smoking and drinking). The odds ratio (95% confidence interval) of log-transformed age, BMI, log-transformed ALT and log-transformed GGT for the presence of MS was 2.180 (1.097-4.334), 1.618 (1.523-1.719), 1.944 (1.299-2.907) and 1.714 (1.272-2.311), respectively.Even after adjustment for other liver enzyme levels, ALT and GGT were still significantly associated with MS in our study, whereas Kawada 1 showed that GGT was the only liver enzyme significantly associated with MS. One possible explanation for the difference may be the study population. The study of Kawada was a prospective community-based cohort focusing on the risk factors for the new onset of MS, with 2 years of follow up, and individuals with diabetes, hypertension, dyslipidaemia, hyperuricaemia and coronary and ⁄ or cerebrovascular disease were excluded from the study. 1 However, in our study we enrolled all participants with and without current MS, even though it was a cross-sectional study. 2 Another