title: Serum γ-Glutamyl Transferase Is Inversely Associated with Bone Mineral Density Independently of Alcohol Consumption.
abstract: BACKGROUND
  γ-Glutamyl transferase (GGT) is a well-known marker of chronic alcohol consumption or hepatobiliary diseases. A number of studies have demonstrated that serum levels of GGT are independently associated with cardiovascular and metabolic disorders. The purpose of this study was to test if serum GGT levels are associated with bone mineral density (BMD) in Korean adults.
  
  
  METHODS
  A total of 462 subjects (289 men and 173 women), who visited Severance Hospital for medical checkup, were included in this study. BMD was measured using dual energy X-ray absorptiometry. Cross-sectional association between serum GGT and BMD was evaluated.
  
  
  RESULTS
  As serum GGT levels increased from the lowest tertile (tertile 1) to the highest tertile (tertile 3), BMD decreased after adjusting for confounders such as age, body mass index, amount of alcohol consumed, smoking, regular exercise, postmenopausal state (in women), hypertension, diabetes mellitus, and hypercholesterolemia. A multiple linear regression analysis showed a negative association between log-transformed serum GGT levels and BMD. In a multiple logistic regression analysis, tertile 3 of serum GGT level was associated with an increased risk for low bone mass compared to tertile 1 (odds ratio, 2.271; 95% confidence interval, 1.340 to 3.850; P=0.002).
  
  
  CONCLUSIONS
  Serum GGT level was inversely associated with BMD in Korean adults. Further study is necessary to fully elucidate the mechanism of the inverse relationship.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea.
authors.forename: Han Seok
authors.initials: HS
authors.lastname: Choi
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.|Severance Check-up, Severance Hospital, Yonsei University Health System, Seoul, Korea.|Severance Executive Healthcare Clinic, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors.forename: Kwang Joon
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yumie
authors.initials: Y
authors.lastname: Rhee
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea. lsk@yuhs.ac.
authors.forename: Sung Kil
authors.initials: SK
authors.lastname: Lim
keywords: Bone density; Gamma-glutamyltransferase; Metabolic disorders