Casual serum triglyceride as a predictor of premature type 2 diabetes mellitus: an 8-year cohort study of middle-aged Japanese workers

U-shaped association between triglyceride and risk of incident diabetes in normoglycemic males with NAFLD: A population-base cohort study

Background: Serum triglyceride (TG) was an important biomarker for nonalcoholic fatty liver disease (NAFLD), and the association between TG and incident type 2 diabetes mellitus is still under debate with some studies suggesting that elevated TG increase the risk of incident T2DM while others indicative of a negative relationship. These controversial findings may be partially due to the inclusion of the participants with NAFLD. The association between TG and incident type 2 diabetes mellitus in people with NAFLD remained unclear. Therefore, this study aimed to characterize the relationship between the baseline TG levels and incident type 2 diabetes mellitus in a male Japanese cohort with NAFLD. Methods: A total of 1221 males with NAFLD were enrolled from the Nagala (NAFLD in the Gifu Area Longitudinal analysis) study conducted from 2004 to 2015. Cox proportional hazards models were performed to examine the relationship between baseline TG concentration and incident type 2 diabetes mellitus. A two-piecewise linear regression model was explored to evaluate the threshold effect of the baseline TG levels on type 2 diabetes mellitus incidence by using a smoothing function. Results: During a median follow-up of 6.05 years, 39 males with NAFLD at baseline developed type 2 diabetes mellitus. The risk of incident type 2 diabetes mellitus was significantly associated with baseline TG concentration in males with NAFLD after fully adjustment for confounders, with per 10 mg/dl elevation in TG levels increasing the risk of incident diabetes by 8.5% (HR=1.085, CI=1.039-1.132; P<0.001). However, no typical dose-dependent positive association between type 2 diabetes mellitus incidence and the TG levels was observed across the TG tertiles. Interestingly, a U-shaped association between TG concentration and risk of incident type 2 diabetes mellitus was revealed by the two-piecewise linear regression analysis. Baseline TG concentration lower than the threshold values (TG <53mg/dl) were negatively associated with risk of incident type 2 diabetes mellitus. With each 10mg/dl increase in baseline TG levels, the risk of incident type 2 diabetes mellitus decreased by nearly 59% (HR=0.413, 95% CI=0.220-0.778). In contrast, when TG levels were higher than the threshold values (TG>53mg/dl), the risk of incident diabetes increased 9.1% with every 10mg TG elevation (HR=1.091, 95% CI=1.046-1.137). Conclusions: A U-shaped relationship was observed between baseline TG levels and incident type 2 diabetes mellitus in a male normoglycemic Japanese population with NAFLD, although extrapolation of the finding to other populations should be made with caution.

Identification of the Chinese Population That Can Benefit Most From Postprandial Lipid Testing: Validation of the Use of Oral Fat Tolerance Testing in Clinical Practice

BACKGROUND

Dyslipidemia has become increasingly prevalent in recent decades. Blood lipid concentrations are significantly influenced by diet; however, postprandial triglyceride concentration (PTG) is not often measured. PTG can reflect the risks of diabetes and cardiovascular disease, but not all individuals would benefit from PTG testing.

OBJECTIVE

The aim of the present study was to determine the PTG response in a Chinese cohort and identify who would benefit from diagnostic PTG measurement.

METHODS

A total of 400 Chinese adults were enrolled and underwent oral fat tolerance test (OFTT), which was well tolerated. The participants were assigned to groups according to their fasting triglyceride concentration to evaluate the usefulness of PTG testing. A PTG concentration > 2.5 mmol/L was defined as high (HPTG).

RESULTS

Of the 400 participants, 78.9% showed an undesirable PTG response. Those with FTG ≥1.0 mmol/L had a delayed PTG peak and higher peak values. Seventy-five percent of those with 1.0 mmol/L ≤FTG <1.7 mmol/L had HPTG, of whom 18.6% had impaired glucose tolerance.

CONCLUSIONS

The present data confirm the previously reported predictive value of PTG testing. Moreover, the findings indicate that Chinese people with FTGs of 1.0 -1.7 mmol/L may benefit most from the identification of postprandial hyperlipidemia through OFTT because more than half of them have occult HPTG, which may require treatment. Thus, the detection of HPTG using an OFTT represents a useful means of identifying dyslipidemia and abnormal glucose metabolism early.

CLINICAL TRIAL REGISTRATION

[http://www.chictr.org.cn/index.aspx], identifier ChiCTR1800019514.