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Effects of Vitamin D Supplementation on Insulin Sensitivity and Secretion in Prediabetes.
Rasouli, N, Brodsky, IG, Chatterjee, R, Kim, SH, Pratley, RE, Staten, MA, Pittas, AG, ,
The Journal of clinical endocrinology and metabolism. 2022;(1):230-240
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Abstract
CONTEXT Vitamin D regulates glucose homeostasis pathways, but effects of vitamin D supplementation on β-cell function remain unclear. OBJECTIVE To investigate the effects of vitamin D3 supplementation on insulin sensitivity and β-cell function. METHODS This is a prespecified secondary analysis of the Vitamin D and Type 2 Diabetes study. Overweight/obese adults at high risk for type 2 diabetes (prediabetes) were randomly treated with vitamin D3 4000 IU or matching placebo daily for 24 months. MAIN OUTCOME Disposition index (DI), as an estimate of β-cell function, was calculated as the product of Homeostasis Model Assessment 2 indices derived from C-peptide values (HOMA2%Scpep) and C-peptide response during the first 30 minutes of a 75-g oral glucose tolerance test (OGTT). RESULTS Mean age was 60.5 ± 9.8 years and body mass index was 31.9 ± 4.4 kg/m2. Mean serum 25(OH)D level increased from 27.9 ± 10.3 ng/mL at baseline to 54.9 ng/mL at 2 years in the vitamin D group and was unchanged (28.5 ± 10.0 ng/mL) in the placebo group. The baseline DI predicted incident diabetes independent of the intervention. In the entire cohort, there were no significant differences in changes in DI, HOMA2%Scpep, or C-peptide response between the 2 groups. Among participants with baseline 25(OH)D level <12 ng/mL, the mean percent differences for DI between the vitamin D and placebo groups was 8.5 (95% CI, 0.2-16.8). CONCLUSIONS Supplementation with vitamin D3 for 24 months did not improve an OGTT-derived index of β-cell function in people with prediabetes not selected based on baseline vitamin D status; however, there was benefit among those with very low baseline vitamin D status.
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Multiple risk factors for diabetes mellitus in patients with chronic pancreatitis: A multicentre study of 1117 cases.
Olesen, SS, Poulsen, JL, Novovic, S, Nøjgaard, C, Kalaitzakis, E, Jensen, NM, Engjom, T, Tjora, E, Waage, A, Hauge, T, et al
United European gastroenterology journal. 2020;(4):453-461
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Abstract
BACKGROUND Diabetes mellitus is a common complication of chronic pancreatitis. It is traditionally considered to develop as a consequence of beta cell loss, but there might be additional factors. Recent studies have highlighted the importance of type 2 diabetes-related risk factors in this context and population-based studies show increased risk of diabetes following acute pancreatitis. The aim of this study was to explore multiple risk factors for diabetes in patients with chronic pancreatitis. METHODS We conducted a multicentre, cross-sectional study of patients with definitive chronic pancreatitis according to the M-ANNHEIM criteria. We used multivariable logistic regression models to determine risk factors independently associated with diabetes. RESULTS The study included 1117 patients of whom 457 (40.9 %) had diabetes. The mean age was 52.8 ± 14.2 years and 67% were men. On multivariate analysis, parameters indicative of beta cell loss (pancreatic calcification, exocrine insufficiency, pancreatic resection) were confirmed as independent risk factors for diabetes (all p ≤ 0.02). In addition, type 2 diabetes-related risk factors (dyslipidaemia and overweight/obesity) were associated with the presence of diabetes (all p ≤ 0.002). Patients with a history of pancreatic fluid collections (indicative of previous attacks of acute pancreatitis) had a marginally increased risk of diabetes (p = 0.07). CONCLUSION In patients with chronic pancreatitis the presence of diabetes is associated with multiple risk factors including type 2 diabetes-related factors. Our observations attest to the understanding of this entity and may have implications for treatment.
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Disruption of fasting and post-load glucose homeostasis are largely independent and sustained by distinct and early major beta-cell function defects: a cross-sectional and longitudinal analysis of the Relationship between Insulin Sensitivity and Cardiovascular risk (RISC) study cohort.
Mengozzi, A, Tricò, D, Nesti, L, Petrie, J, Højlund, K, Mitrakou, A, Krebs, M, Mari, A, Natali, A, ,
Metabolism: clinical and experimental. 2020;:154185
Abstract
BACKGROUND/AIMS: Uncertainty still exists on the earliest beta-cell defects at the bases of the type 2 diabetes. We assume that this depends on the inaccurate distinction between fasting and post-load glucose homeostasis and aim at providing a description of major beta-cell functions across the full physiologic spectrum of each condition. METHODS In 1320 non-diabetic individuals we performed an OGTT with insulin secretion modeling and a euglycemic insulin clamp, coupled in subgroups to glucose tracers and IVGTT; 1038 subjects underwent another OGTT after 3.5 years. Post-load glucose homeostasis was defined as mean plasma glucose above fasting levels (δOGTT). The analysis was performed by two-way ANCOVA. RESULTS Fasting plasma glucose (FPG) and δOGTT were weakly related variables (stβ = 0.12) as were their changes over time (r = -0.08). Disruption of FPG control was associated with an isolated and progressive decline (approaching 60%) of the sensitivity of the beta-cell to glucose values within the normal fasting range. Disruption of post-load glucose control was characterized by a progressive decline (approaching 60%) of the slope of the full beta-cell vs glucose dose-response curve and an early minor (30%) decline of potentiation. The acute dynamic beta-cell responses, neither per se nor in relation to the degree of insulin resistance appeared to play a relevant role in disruption of fasting or post-load homeostasis. Follow-up data qualitatively and quantitatively confirmed the results of the cross-sectional analysis. CONCLUSION In normal subjects fasting and post-load glucose homeostasis are largely independent, and their disruption is sustained by different and specific beta-cell defects.
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Adding vitamin D3 to the dipeptidyl peptidase-4 inhibitor saxagliptin has the potential to protect β-cell function in LADA patients: A 1-year pilot study.
Zhang, Z, Yan, X, Wu, C, Pei, X, Li, X, Wang, X, Niu, X, Jiang, H, Zeng, X, Zhou, Z
Diabetes/metabolism research and reviews. 2020;(5):e3298
Abstract
AIMS: This trial was conducted to explore the protective effect on β-cell function of adding vitamin D3 to DPP-4 inhibitors to treat patients with latent autoimmune diabetes in adults (LADA). METHODS 60 LADA patients were randomized to group A (n = 21) - conventional therapy with metformin (1-1.7 g/day) and/or insulin treatment; group B (n = 20) - saxagliptin (5 mg/day) plus conventional therapy; and group C (n = 19) - vitamin D3 (2000 IU/day) plus saxagliptin and conventional therapy for 12 months. Fasting and 2-hour postprandial blood samples were collected to measure blood glucose, glycosylated hemoglobin and C-peptide levels at baseline and after 3, 6 and 12 months of treatment. RESULTS During the 12 months of follow-up, the levels of fasting C-peptide (FCP), 2-hour postprandial C-peptide (PCP) and the C-peptide index (CPI, serum C-peptide-to-plasma glucose level ratio) were maintained in group C. In contrast to those in group A and group B, FCP levels decreased significantly in group B, and CPI levels declined significantly in group A during the 1-year treatment (P < .05). Additionally, the levels of GADA titers in group C significantly decreased compared with those at baseline (P < .05), but no significant differences in GADA titers levels were detected in group A and group B. No significant differences were found among the three groups in the levels of FCP, PCP, the CPI or GADA titers. CONCLUSIONS The data suggested that adding 2000 IU/day vitamin D3 to saxagliptin might preserve β-cell function in patients with LADA.
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Exercise to preserve β-cell function in recent-onset Type 1 diabetes mellitus (EXTOD) - a randomized controlled pilot trial.
Narendran, P, Jackson, N, Daley, A, Thompson, D, Stokes, K, Greenfield, S, Charlton, M, Curran, M, Solomon, TPJ, Nouwen, A, et al
Diabetic medicine : a journal of the British Diabetic Association. 2017;(11):1521-1531
Abstract
AIM: Residual β-cell function is present at the time of diagnosis with Type 1 diabetes. Preserving this β-cell function reduces complications. We hypothesized that exercise preserves β-cell function in Type 1 diabetes and undertook a pilot trial to address the key uncertainties in designing a definitive trial to test this hypothesis. METHODS A randomized controlled pilot trial in adults aged 16-60 years diagnosed with Type 1 diabetes within the previous 3 months was undertaken. Participants were assigned to control (usual care) or intervention (exercise consultation every month), in a 1 : 1 ratio for 12 months. The primary outcomes were recruitment rate, drop out, exercise adherence [weeks with ≥ 150 min of self-reported moderate to vigorous physical activity (MVPA)], and exercise uptake in the control group. The secondary outcomes were differences in insulin sensitivity and rate of loss of β-cell function between intervention and control at 6 and 12 months. RESULTS Of 507 individuals who were approached, 58 (28 control, 30 intervention) entered the study and 41 completed it. Participants were largely white European males, BMI 24.8 ± 3.8 kg/m2 , HbA1c 75 ± 25 mmol/mol (9 ± 2%). Mean level of objectively measured MVPA increased in the intervention group (mean 243 to 273 min/week) and 61% of intervention participants reached the target of ≥ 150 min/week of self-reported MVPA on at least 42 weeks of the year. Physical activity levels fell slightly in the control group (mean 277 to 235 min of MVPA/week). There was exploratory evidence that intervention group became more insulin sensitive and required less insulin. However, the rate of loss of β-cell function appeared similar between the groups, although the change in insulin sensitivity may have affected this. CONCLUSION We show that it is possible to recruit and randomize people with newly diagnosed Type 1 diabetes to a trial of an exercise intervention, and increase and maintain their exercise levels for 12 months. Future trials need to incorporate measures of greater adherence to exercise training targets, and include more appropriate measures of β-cell function. (Clinical Trials Registry No; ISRCTN91388505).
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Stimulated urine C-peptide creatinine ratio vs serum C-peptide level for monitoring of β-cell function in the first year after diagnosis of Type 1 diabetes.
Tatovic, D, Luzio, S, Dunseath, G, Liu, Y, Alhadj Ali, M, Peakman, M, Dayan, CM, ,
Diabetic medicine : a journal of the British Diabetic Association. 2016;(11):1564-1568
Abstract
AIMS: To determine if urine C-peptide/creatinine ratio is a useful tool for monitoring β-cell function in new-onset Type 1 diabetes. METHODS Data were obtained from a prospective immunomodulation study in people with Type 1 diabetes ≤ 3 months from diagnosis, with a standard mixed-meal tolerance test and measurement of urine C-peptide/creatinine ratio carried out at 0, 3, 6, 9 and 12 months. The change in the insulin-dose-adjusted HbA1c level was also correlated with the change in serum/urine C-peptide level during the 12-month follow-up period. RESULTS A significant reduction in urine C-peptide/creatinine ratio, measured after a mixed-meal, was reached at 9 months (-45.4%), whilst the reduction in stimulated serum C-peptide level reached significance after 3 months (-54.7%) in placebo-treated participants. Neither change in stimulated serum C-peptide nor change in urine C-peptide level correlated with each other, and nor did change in insulin-dose-adjusted HbA1c level in the first 6 months, but all measures correlated significantly in the second half of the 12-month follow-up period. CONCLUSION Mixed-meal-stimulated urine C-peptide/creatinine ratio was similar to, although less sensitive than, stimulated serum C-peptide level in monitoring β-cell function during the first year after diagnosis. Because the former is significantly less invasive, it warrants inclusion in further studies in Type 1 diabetes and may represent an attractive alternative outcome measure in cohort studies and in children.
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Factors associated with beta-cell dysfunction in type 2 diabetes: the BETADECLINE study.
Russo, GT, Giorda, CB, Cercone, S, Nicolucci, A, Cucinotta, D, ,
PloS one. 2014;(10):e109702
Abstract
AIMS: Beta-cell dysfunction is an early event in the natural history of type 2 diabetes. However, its progression is variable and potentially influenced by several clinical factors. We report the baseline data of the BetaDecline study, an Italian prospective multicenter study on clinical predictors of beta-cell dysfunction in type 2 diabetes. MATERIALS AND METHODS Clinical, lifestyle, and laboratory data, including circulating levels of inflammatory markers and non-esterified fatty acids, were collected in 507 type 2 diabetic outpatients on stable treatment with oral hypoglycemic drugs or diet for more than 1 year. Beta-cell dysfunction was evaluated by calculating the proinsulin/insulin ratio (P/I). RESULTS At baseline, the subjects in the upper PI/I ratio quartile were more likely to be men and receiving secretagogue drugs; they also showed a borderline longer diabetes duration (P = 0.06) and higher serum levels of glycated hemoglobin (HbA1c), fasting blood glucose, and triglycerides. An inverse trend across all PI/I quartiles was noted for BMI and serum levels of total cholesterol (T-C), LDL-C, HDL-C and C reactive protein (CRP), and with homeostatic model assessment (HOMA-B) and HOMA of insulin resistance (HOMA-IR) values (P<0.05 for all). At multivariate analysis, the risk of having a P/I ratio in the upper quartile was higher in the subjects on secretagogue drugs (odds ratio [OR] 4.2; 95% confidence interval [CI], 2.6-6.9) and in the males (OR 1.8; 95% CI, 1.1-2.9). CONCLUSIONS In the BetaDecline study population, baseline higher PI/I values, a marker of beta-cell dysfunction, were more frequent in men and in patients on secretagogues drugs. Follow-up of this cohort will allow the identification of clinical predictors of beta-cell failure in type 2 diabetic outpatients.
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Determining pancreatic β-cell compensation for changing insulin sensitivity using an oral glucose tolerance test.
Solomon, TP, Malin, SK, Karstoft, K, Knudsen, SH, Haus, JM, Laye, MJ, Pedersen, M, Pedersen, BK, Kirwan, JP
American journal of physiology. Endocrinology and metabolism. 2014;(9):E822-9
Abstract
Plasma glucose, insulin, and C-peptide responses during an OGTT are informative for both research and clinical practice in type 2 diabetes. The aim of this study was to use such information to determine insulin sensitivity and insulin secretion so as to calculate an oral glucose disposition index (DI(OGTT)) that is a measure of pancreatic β-cell insulin secretory compensation for changing insulin sensitivity. We conducted an observational study of n = 187 subjects, representing the entire glucose tolerance continuum from normal glucose tolerance to type 2 diabetes. OGTT-derived insulin sensitivity (S(I OGTT)) was calculated using a novel multiple-regression model derived from insulin sensitivity measured by hyperinsulinemic euglycemic clamp as the independent variable. We also validated the novel S(I OGTT) in n = 40 subjects from an independent data set. Plasma C-peptide responses during OGTT were used to determine oral glucose-stimulated insulin secretion (GSIS(OGTT)), and DI(OGTT) was calculated as the product of S(I OGTT) and GSIS(OGTT). Our novel S(I OGTT) showed high agreement with clamp-derived insulin sensitivity (typical error = +3.6%; r = 0.69, P < 0.0001) and that insulin sensitivity was lowest in subjects with impaired glucose tolerance and type 2 diabetes. GSIS(OGTT) demonstrated a significant inverse relationship with S(I OGTT). GSIS(OGTT) was lowest in normal glucose-tolerant subjects and greatest in those with impaired glucose tolerance. DI(OGTT) was sequentially lower with advancing glucose intolerance. We hereby derive and validate a novel OGTT-derived measurement of insulin sensitivity across the entire glucose tolerance continuum and demonstrate that β-cell compensation for changing insulin sensitivity can be readily calculated from clinical variables collected during OGTT.
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Sitagliptin and pioglitazone provide complementary effects on postprandial glucose and pancreatic islet cell function.
Alba, M, Ahrén, B, Inzucchi, SE, Guan, Y, Mallick, M, Xu, L, O'Neill, EA, Williams-Herman, DE, Kaufman, KD, Goldstein, BJ
Diabetes, obesity & metabolism. 2013;(12):1101-10
Abstract
AIMS: The effects of sitagliptin and pioglitazone, alone and in combination, on α- and β-cell function were assessed in patients with type 2 diabetes. METHODS Following a 6-week diet/exercise period, 211 patients with HbA1c of 6.5-9.0% and fasting plasma glucose of 7.2-14.4 mmol/l were randomized (1 :1 :1 : 1) to sitagliptin, pioglitazone, sitagliptin + pioglitazone or placebo. At baseline and after 12 weeks, patients were given a mixed meal followed by frequent blood sampling for measurements of glucose, insulin, C-peptide and glucagon. RESULTS After 12 weeks, 5-h glucose total area under the curve (AUC) decreased in all active treatments versus placebo; reduction with sitagliptin + pioglitazone was greater versus either monotherapy. The 5-h insulin total AUC increased with sitagliptin versus all other treatments and increased with sitagliptin + pioglitazone versus pioglitazone. The 3-h glucagon AUC decreased with sitagliptin versus placebo and decreased with sitagliptin + pioglitazone versus pioglitazone or placebo. Φ(s), a measure of dynamic β-cell responsiveness to above-basal glucose concentrations, increased with either monotherapy versus placebo and increased with sitagliptin + pioglitazone versus either monotherapy. The insulin sensitivity index (ISI), a composite index of insulin sensitivity, improved with pioglitazone and sitagliptin + pioglitazone versus placebo. The disposition index, a measure of the relationship between β-cell function and insulin sensitivity, improved with all active treatments versus placebo. CONCLUSIONS Sitagliptin and pioglitazone enhanced β-cell function (increasing postmeal Φ(s)), and sitagliptin improved α-cell function (decreasing postmeal glucagon) after 12 weeks in patients with type 2 diabetes. Through these complementary mechanisms of action, the combination of sitagliptin and pioglitazone reduced postmeal glucose more than either treatment alone.
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Elevated 1-hour postload plasma glucose levels identify subjects with normal glucose tolerance but impaired β-cell function, insulin resistance, and worse cardiovascular risk profile: the GENFIEV study.
Bianchi, C, Miccoli, R, Trombetta, M, Giorgino, F, Frontoni, S, Faloia, E, Marchesini, G, Dolci, MA, Cavalot, F, Cavallo, G, et al
The Journal of clinical endocrinology and metabolism. 2013;(5):2100-5
Abstract
CONTEXT In subjects with normal glucose tolerance (NGT) 1-hour postload plasma glucose (1-h oral glucose tolerance test [OGTT]) of >155 mg/dL predicts type 2 diabetes (T2DM) and is associated with subclinical atherosclerosis. OBJECTIVE The purpose of this study was to evaluate β-cell function, insulin resistance, and cardiovascular risk profile in subjects with NGT with a 1-h OGTT glucose of >155 mg/dL. PATIENTS AND METHODS The GENFIEV (Genetics, PHYsiopathology, and Evolution of Type 2 diabetes) study is a multicenter study recruiting individuals at high risk of T2DM. A total of 926 subjects underwent a 75-g OGTT for assessment of plasma glucose and C-peptide for mathematical modeling of β-cell function (derivative and proportional control). Fasting insulin, lipid profile, and clinical parameters were determined as well. RESULTS A 1-hour OGTT glucose of >155 mg/dL was found in 39% of subjects with NGT, 76% with impaired fasting glucose (IFG), 90% with impaired glucose tolerance (IGT), and 99% and 98% with IFG + IGT or newly diagnosed T2DM, respectively. Among subjects with NGT (n = 474), those with 1-hour OGTT glucose of >155 mg/dL were more insulin-resistant and had worse β-cell function than those with 1-hour OGTT glucose of ≤155 mg/dL. Moreover, glycosylated hemoglobin, blood pressure, low-density lipoprotein cholesterol, and triglycerides were higher in subjects with NGT with 1-hour OGTT glucose of >155 mg/dL, whereas high-density lipoprotein cholesterol was lower compared with that in subjects with NGT with 1-hour OGTT glucose of ≤155 mg/dL. Compared with subjects with IGT, those with NGT with 1-hour OGTT glucose of >155 mg/dL had comparable cardiovascular risk profile and insulin resistance but slightly better β-cell function. CONCLUSIONS Among subjects with NGT, those with 1-hour OGTT glucose of >155 mg/dL showed lower insulin sensitivity, impaired β-cell function, and worse cardiovascular risk profile and therefore are at greater risk of developing T2DM and cardiovascular disease.