Objectives. To examine gender-specific associations between γ-glutamyltransferase (GGT) and incident type 2 diabetes mellitus in a representative population-based sample in Germany.
Design. Prospective population-based study.
Methods. The study was based on 1851 men and 1836 women (aged 25–64 years) who participated in the first Monitoring Trends and Determinants on Cardiovascular Diseases (MONICA) Augsburg Survey 1984/1985, and who were free of diabetes at baseline. Incident cases of type 2 diabetes were assessed using follow-up questionnaires in 1987/1988, 1997/1998 and 2002/2003 and were validated with medical records. Gender-specific hazard ratios (HRs) were estimated from Cox proportional hazard models.
Results. A total of 172 cases of incident type 2 diabetes amongst men and 109 amongst women were registered during a mean follow-up period of 14.7 years. In both sexes the risk of type 2 diabetes increased with increasing levels of serum GGT. After multivariable adjustment HRs for incident type 2 diabetes across GGT categories (<25th, <50th, <75th, <87.5th and ≥87.5th percentiles) were 1.0, 1.81, 2.37, 3.41 and 4.24 (P-value for trend <0.0001) in men and 1.0, 1.42, 1.48, 1.95 and 2.41 (P-value for trend 0.0179) in women. Obesity appeared to be more strongly associated with type 2 diabetes in women with GGT equal or greater than the median compared to women with GGT below the median. However, in men the association between obesity and type 2 diabetes was almost identical in the two groups.
Conclusions. The GGT is an important predictor for incident type 2 diabetes in men and women from the general population.