Serum γ‐glutamyltransferase and development of impaired fasting glucose or type 2 diabetes in middle‐aged Japanese men

Abstract

Nakanishi N, Nishina K, Li W, Sato M, Suzuki K, Tatara K (Osaka University Graduate School of Medicine, Osaka; and Japan Labor and Welfare Association, Tokyo; Japan). Serum γ‐glutamyltransferase and development of impaired fasting glucose or type 2 diabetes in middle‐aged Japanese men. J Intern Med 2003; 254: 287–295. Objective. To investigate the association between serum γ‐glutamyltransferase (GGT) and risk for development of diabetes. Design. Longitudinal study (followed from 1994 to 2001). Setting. A work site in Japan. Subjects. A total of 2918 Japanese male office workers aged 35–59 years who did not have impaired fasting glucose (IFG) (a fasting plasma glucose concentration of 6.1–6.9 mmol L⁻¹), type 2 diabetes (a fasting plasma glucose concentration of 7.0 mmol L⁻¹ or receipt of hypoglycaemic medication), medication for hypertension or hepatitis, alanine aminotransferase concentrations higher than three times the upper limit of the reference range or a history of cardiovascular disease at study entry. Main outcome measure. Incidence of IFG or type 2 diabetes over a 7‐year period. Results. With adjustment for potential risk factors for diabetes, the relative risk for IFG compared with serum GGT −1 was 1.23 (95% CI, 0.79–1.90), 1.50 (CI, 0.97–2.32) and 1.70 (CI, 1.07–2.71) with serum GGT of 16–24, 25–43 and 44 U L⁻¹, respectively (P for trend = 0.014). The respective relative risks for type 2 diabetes compared with serum GGT −1 were 2.54 (CI, 1.29–5.01), 2.64 (CI, 1.33–5.23) and 3.44 (CI, 1.69–6.70) (P for trend = 0.002). From stratified analyses by body mass index (BMI) and alcohol intake, a stronger linear association between serum GGT and development of IFG or type 2 diabetes was found in men with a BMI 23.2 kg m⁻² in both those who drank −1 of ethanol. Conclusions. The risk for development of IFG or type 2 diabetes increased in a dose‐dependent manner as serum GGT increased in middle‐aged Japanese men. The increased relative risk for IFG or type 2 diabetes associated with serum GGT was more pronounced in obese men.