Discriminatory ability of simple OGTT-based beta cell function indices for prediction of prediabetes and type 2 diabetes:the CODAM study

Aims/hypothesis The hyperglycaemic clamp technique and the frequently sampled IVGTT are unsuitable techniques to assess beta cell function (BCF) in large cohorts. Therefore, the aim of this study was to evaluate the discriminatory ability of simple OGTT-based BCF indices for prediction of prediabetes (meaning impaired fasting glucose and/or impaired glucose tolerance) and type 2 diabetes.Methods Glucose metabolism status was assessed by 2 h 75 g OGTT at baseline (n = 476, mean age 59.2 years, 38.7% women) and after 7 years of follow-up (n = 416) in the Cohort on Diabetes and Atherosclerosis Maastricht (CODAM) study (1999-2009). Baseline plasma glucose, insulin and C-peptide values during OGTTs were used to calculate 21 simple indices of BCF. Disposition indices (BCF index x Matsuda index), to compensate for the prevailing level of insulin resistance, were calculated for the BCF indices with the best discriminatory abilities. The discriminatory ability of the BCF indices was estimated by the area under the receiver operating characteristics curve (ROC AUC) with an outcome of incident prediabetes (n = 73) or type 2 diabetes (n = 60 and n = 18 cases, respectively, in individuals who were non-diabetic or had normal glucose metabolism at baseline).Results For incident prediabetes (n = 73), all ROC AUCs were less than 70%, whereas for incident type 2 diabetes, I-30/I-0, CP30/CP0, Delta I-30/Delta G(30), Delta CP30/Delta G(30) (where I, CP and G are the plasma concentrations of insulin, C-peptide and glucose, respectively, at the times indicated), and corrected insulin response at 30 min had ROC AUCs over 70%. In at-baseline non-diabetic individuals, disposition indices Delta I-30/Delta G(30), Delta CP30/Delta G(30) and corrected insulin response at 30 min had ROC AUCs of over 80% for incident type 2 diabetes. Moreover, these BCF disposition indices had significantly better discriminatory abilities for incident type 2 diabetes than the Matsuda index alone.Conculusion/interpretation BCF indices reflecting early-phase insulin secretion have the best ability to discriminate individuals who will develop prediabetes and type 2 diabetes. Of these, Delta CP30/Delta G(30), often referred to as the C-peptidogenic index, performed consistently well.</p

The Maastricht FFQ:Development and validation of a comprehensive food frequency questionnaire for the Maastricht study

Objective: To develop and validate a comprehensive food frequency questionnaire (FFQ) for The Maastricht Study, a population-based prospective cohort study in Maastricht, The Netherlands. Research Methods & Procedures: Item selection for the FFQ was based on explained variation and contribution to intake of energy and 24 nutrients. For validation, the FFQ was filled out by 135 participants (25-70 years) of the Nutrition Questionnaires plus study. Per person, on average 2.8 (range 1 to 5) telephone-based 24h dietary recalls (24hRs), two 24h urinary samples and one blood sample were available. Validity of 54 nutrients and 22 food groups was assessed by ranking agreement, correlation coefficients, attenuation factors, and ultimately de-attenuated correlation coefficients (validity coefficients). Results: Median correlation coefficients for energy and macronutrients, micronutrients and food groups were 0.45, 0.36 and 0.38, respectively. Median de-attenuated correlation coefficients were 0.53 for energy and macronutrients, 0.45 for micronutrients and 0.64 for food groups, being >0.50 for 18 out of 22 macronutrients and 16 out of 30 micronutrients, and >0.50 for 17 out of 22 food groups. The FFQ underestimated protein and potassium intake compared to 24h urinary nitrogen and potassium excretion by -18% and -2%, respectively. Correlation coefficients ranged from 0.50 and 0.55 for (fatty) fish intake and plasma EPA and DHA, and from 0.26-0.42 between fruit and vegetable intake and plasma carotenoids. Conclusion: Overall, the validity of the 253-item Maastricht-FFQ is good. The comprehensiveness of this FFQ make it well-suited for use in The Maastricht Study and similar populations

Associations of Dietary Glucose, Fructose, and Sucrose with beta-Cell Function, Insulin Sensitivity, and Type 2 Diabetes in the Maastricht Study

The associations of glucose, fructose, and sucrose intake with type 2 diabetes mellitus (T2DM) have been inconsistent. Furthermore, there is a lack of studies focusing on early markers of T2DM that provide insight into the process of T2DM progression: impaired pancreatic beta-cell function (BCF) and insulin sensitivity. This study evaluated associations cross-sectionally in a population-based cohort consisting of 2818 individuals (mean +/- SD age 59.7 +/- 8.18, 49.5% male, n = 120 newly diagnosed T2DM). Glucose, fructose, and sucrose intake were assessed by a food frequency questionnaire. Glucose metabolism status, insulin sensitivity, and BCF were measured by a seven-points oral glucose tolerance test. Linear regression analysis revealed a positive association of glucose intake with insulin sensitivity in the fully adjusted model (standardized beta (95% CI) 0.07 (0.05, 0.14) SD for &gt;= 23 g vs. &lt;10 g of glucose). Fructose and sucrose intake were not associated with insulin sensitivity after full adjustments. In addition, no associations of dietary glucose, fructose, and sucrose with BCF were detected. In conclusion, higher intake of glucose, not fructose and sucrose, was associated with higher insulin sensitivity, independent of dietary fibre. No convincing evidence was found for associations of dietary glucose, fructose, and sucrose with BCF in this middle-aged population.</p

High redshift radio galaxies from the Molonglo Catalogue. II

Restricted Access.We report further results from the ongoing study of radio galaxies from the Molonglo Reference Catalogue are reported. The sources were selected to have 408 MHz flux densities greater than 0.95 Jy and low frequency spectral indices steeper than -0.9. VLA 6-cm maps, optical identifications and redshifts for 18 sources are presented. Most of these sources are identified with faint galaxies, many of which have extended optical structures with morphologies characteristic of high redshift (z greater than 1) radio galaxies. Long slit spectroscopic observations have yielded redshifts for all of the galaxies, three of which have z greater than 2. Spectrophotometry of 1 Jy and the 3CR samples are used to distinguish between an L (emission line) versus L (radio) correlation as opposed to an L (emission line) versus redshift correlation. The results strongly support an intrinsic L (emission line) versus L (radio) correlation. The structures of the sources in this and other 1 Jy samples are substantially different fro the 3C sources, the 1 Jy galaxies having stronger cores and jets