Serum Alanine Transaminase as a Predictor of Type 2 Diabetes Incidence: The Yuport Prospective Cohort Study

Association between serum ALT levels and incidence of new-onset diabetes in general population of Japanese: a longitudinal observational study (ISSA-CKD)

OBJECTIVE

We aimed to clarify the relationship between serum alanine transaminase (ALT) levels and incidence of new-onset diabetes in a Japanese general population.

SETTING

Population-based retrospective cohort study using annual health check-up data for residents of Iki City, Nagasaki Prefecture, Japan.

PARTICIPANTS

A total of 5330 Japanese individuals (≥30 years old) without diabetes at baseline were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

Serum ALT levels were determined using an enzymatic method and were classified into gender-specific quartile groups as follows: group 1 (3-16 U/L in men and 3-13 U/L in women), group 2 (17-21 U/L in men and 14-16 U/L in women), group 3 (22-29 U/L in men and 17-22 U/L in women) and group 4 (30-428 U/L in men and 23-268 U/L in women). The study outcome was the incidence of diabetes (fasting glucose ≥7.0 mmol/L, non-fasting glucose ≥11.1 mmol/L, glycated haemoglobin ≥6.5% or use of glucose-lowering therapies).

RESULTS

After an average follow-up period of 5.0 years, 279 individuals developed diabetes. The incidence rate of diabetes increased with elevation of serum ALT levels (0.7% per 100 person-years in group 1, 0.9% in group 2, 0.9% in group 3 and 1.7% in group 4) (p<0.001 for trend). This association was significant after adjustment for other risk factors including age, sex, obesity, hypertension, dyslipidaemia, smoking, current daily alcohol intake and regular exercise (p<0.001 for trend). Comparable associations were observed between men and women (p=0.459 for interaction).

CONCLUSION

Serum ALT levels were associated with future development of diabetes in the general Japanese population.

Prediction of new onset of diabetes mellitus during a 10-year period by using a combination of levels of alanine aminotransferase and γ-glutamyl transferase

Levels of alanine aminotransferase (ALT) and γ-glutamyl transferase (GGT) have been reported to be associated with increased risk of diabetes mellitus (DM). However, whether a combination of levels of ALT and GGT predicts new onset of DM better than does ALT or GGT alone in both males and females has not fully been addressed. We investigated the relationship between the combination of ALT and GGT and DM development during a 10-year follow-up period in 13,919 subjects (male/female: 8,983/4,936; age 48 ± 10 years) who received health examinations. During the 10-year period, 617 males (6.9%) and 153 females (3.1%) had new onset of DM. Multivariable Cox proportional hazard models with a restricted cubic spline showed that hazard ratios (HRs) of DM development increased with higher levels of ALT and GGT at baseline in both sexes after adjustment of confounding factors. When divided into 4 subgroups of high (H-) and low (L-) levels of ALT (male/female: 27/21 U/L) and GGT (male/female: 43/23 U/L) using cutoff values shown by receiver operating characteristic curve analyses, the adjusted HR in the H-ALT/H-GGT group was significantly higher than HR in the L-ALT/L-GGT group as the reference in males (HR [95% confidence interval]: 1.73[1.36-2.20], p < 0.001) but was not significantly higher in females (1.50 [0.97-2.33], p = 0.065). The addition of the combination of H-ALT/H-GGT to traditional risk factors with and without H-ALT or H-GGT alone significantly improved the discriminatory capability for predicting development of DM. In conclusion, the combination of H-ALT/H-GGT efficiently predicts development of DM in male individuals but not significantly in female individuals.