ORIGINAL ARTICLE The product of triglycerides and glucose in comparison with fasting plasma glucose did not improve diabetes prediction Mohsen Janghorbani • Siedeh Zinab Almasi • Masoud Amini Received: 6 November 2014 / Accepted: 26 December 2014 Ó Springer-Verlag Italia 2015 Abstract Aims Previous study has reported that triglycerides-glu- cose (TyG) index, a product of triglycerides and fasting plasma glucose (FPG), might be useful in the prediction of incident type 2 diabetes (T2D). We evaluated the ability of the TyG index compared to FPG and OGTT as possible diabetes predictor in nondiabetic first-degree relatives (FDRs) of patients with T2D. Methods A total of 1,488 FDRs without diabetes of consecutive patients with T2D 30–70 years old (361 men and 1,127 women) were examined and followed for a mean (SD) of 6.9 (1.7) years for diabetes incidence. We exam- ined the incidence of diabetes across quartiles of the TyG index and plotted a receiver operating characteristic (ROC) curve to assess discrimination. At baseline and through follow-up, participants underwent a standard 75-g two- hour oral glucose tolerance test. Results During 10,124 person-years of follow-up, 41 men and 154 women developed T2D. Those in the top quartile of TyG index were 3.4 times more likely to develop T2D than those in the bottom quartile (odds ratio 3.36; 95 % CI 1.83, 6.19). On ROC curve analysis, a higher area under the ROC was found for FPG (76.2; 95 % CI 71.9, 80.6), 1-hPG (81.0, 95 % CI 77.2, 84.9) and 2-hPG (76.5; 95 % CI 72.3, 80.8) than for TyG index (65.1; 95 % CI 60.5, 69.7). Conclusions TyG index is predicted T2D in high-risk individuals in Iran but FPG, 1-hPG and 2-hPG appeared to be more robust predictor of T2D in our study population. Keywords Diabetes mellitus Á First-degree relatives Á Glucose tolerance Á Incidence Á Risk score Á Triglycerides and glucose index Á Product of fasting triglycerides and glucose Introduction Type 2 diabetes mellitus (T2D) is an important and growing public health problem worldwide [1]. Based on a recent report by the International Diabetes Federation (IDF), Middle East and North Africa region currently has the highest regional prevalence of T2D, and by 2030 it is expected to have the second largest proportional increase after Africa [2]. Based on available data of adults aged 20–70 years, the IDF Atlas of Diabetes [1] estimated a point prevalence of 9.33 % for T2D in 2011, and it has also predicted that this figure would rise to 13.15 % by 2030. T2D prevalence in Iran is significantly higher than its neighboring countries Pakistan (6.7 % for 2007) [3] and Turkey (7.2 %, for 1997–1998) [4]. On the other hand, our figures often fall below the prevalence rates observed in Arab communities [5]. Available reports of T2D preva- lence among Middle Eastern countries vary substantially, ranging from 2.8 % in Israel [6] to 29 % in Bahrain [7]. In a 2009 systematic review, a prevalence rate of 10.5 % (95 % CI 8.6, 12.7 %) in the region was recorded [8]. Managed by Massimo Porta. M. Janghorbani (&) Á M. Amini Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran e-mail: janghorbani@hlth.mui.ac.ir; janghorbani@yahoo.com M. Janghorbani Á S. Z. Almasi Department of Epidemiology and Biostatistics, School of Public Health, Isfahan University of Medical Sciences, Isfahan, Iran M. Janghorbani Á S. Z. Almasi Á M. Amini Department of Epidemiology and Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran 123 Acta Diabetol DOI 10.1007/s00592-014-0709-5