Vitamin D Role and Use in Prediabetes

ObjectiveTo review the role of vitamin D in prediabetes on the basis of evidence from human studies.MethodsEnglish-language literature in MEDLINE (January 1969-July 2009) was searched for observational studies and randomized controlled trials of vitamin D deficiency and treatment in prediabetes, including impaired fasting glucose, impaired glucose tolerance, and metabolic syndrome. Search terms included hyperglycemia, glucose, glycohemoglobin, insulin resistance, diabetes, homeostasis model assessment, insulin secretion, vitamin D, and related terms. Publications were also identified from review articles and references in the found articles. Abstracts, conference proceedings, case reports, and letters were excluded. Articles concerning only type 1 and type 2 diabetes, hemodialysis, or hyperparathyroidism and studies in children were also excluded.ResultsVitamin D insufficiency is defined by a circulating 25-hydroxyvitamin D concentration less than 30 ng/mL, and it is prevalent in the United States (77% of the population). Most cross-sectional and prospective studies in various populations show inverse association between circulating 25-hydroxyvitamin D and fasting plasma glucose, impaired glucose tolerance, hemoglobin A_1c, metabolic syndrome, and incidence of prediabetes. A few clinical trials suggest beneficial effect of vitamin D supplementation in prediabetes, including improved insulin secretion, basal fasting insulin sensitivity, and postprandial peripheral insulin resistance. The limitations of the studies are small sample size, short duration of follow-up, lack of control groups, and inability to achieve vitamin D sufficiency with treatment.ConclusionAvailable data suggest that achieving vitamin D sufficiency may be beneficial in patients with prediabetes, although clinical trials are needed to provide evidence-based recommendations. (Endocr Pract. 2010;16:476-485)     

Relationship between glycated hemoglobin and glucose concentrations in the adult Galician population: selection of optimal glycated hemoglobin cut-off points as a diagnostic tool of diabetes mellitus

Aims/hypothesisTo analyze the relationship between glucose and glycated hemoglobin (HbA_1c) in the adult Galician population, evaluate the use of HbA_1c for the screening and diagnosis of diabetes, and calculate the diagnostic threshold required for this purpose.MethodsWe analyzed data on 2848 subjects (aged 18–85 years) drawn from a study undertaken in 2004 to assess the prevalence of diabetes in Galicia. For study purposes, diabetes was defined using the criteria recommended in 2002. Participants were classified into four glucose-based groups. The relationship between glucose and HbA_1c was described using linear regression models, generalized additive models and Spearman's correlation. Diagnostic capacity was assessed, and optimal HbA_1c cut-off points were calculated as a diabetes marker using the receiver operating characteristic curve.ResultsPrevalence of pre-diabetes, unknown diabetes and known diabetes was 20.86, 3.37 and 4.39%, respectively. The correlations between HbA_1c and fasting glucose were higher than those obtained for HbA_1c and glycemia at 2 h of the oral glucose overload (0.344 and 0.270, respectively). Taking glucose levels as the gold standard, a greater discriminatory capacity was obtained for HbA_1c (area under de cruve: 0.839, 95% confidence intervals: 0.788–0.890). Based on the study criteria, the optimal minimum and maximum HbA_1c values were 5.9% and 6.7%, respectively.Conclusions/interpretationHbA_1c did not prove superior to glycemia for diagnosis of diabetes in the adult Galician population, and cannot therefore be used to replace the oral glucose tolerance test for screening and diagnosis purposes. Indeed, determination of glucose is essential to verify the diagnosis in the majority of cases.     

Impact of Vitamin D Replacement on Markers of Glucose Metabolism and Cardio-Metabolic Risk in Women with Former Gestational Diabetes—A Double-Blind,Randomized Controlled Trial

Gestational Diabetes Mellitus (GDM) and vitamin D deficiency are related to insulin resistance and impaired beta cell function, with heightened risk for future development of diabetes. We evaluated the impact of vitamin D supplementation on markers of glucose metabolism and cardio metabolic risk in Asian women with former GDM and hypovitaminosis D. In this double blind, randomized controlled trial, 26 participants were randomized to receive either daily 4000 IU vitamin D3 or placebo capsules. 75g Oral Glucose Tolerance Test (OGTT) and biochemistry profiles were performed at baseline and 6 month visits. Mathematical models, using serial glucose, insulin and C peptide measurements from OGTT, were employed to calculate insulin sensitivity and beta cell function. Thirty three (76%) women with former GDM screened had vitamin D level of <50 nmol/L at baseline. Supplementation, when compared with placebo, resulted in increased vitamin D level (+51.1 nmol/L vs 0.2 nmol/L, p<0.001) and increased fasting insulin (+20% vs 18%, p = 0.034). The vitamin D group also demonstrated a 30% improvement in disposition index and an absolute 0.2% (2 mmol/mol) reduction in HbA_1c. There was no clear change in insulin sensitivity or markers of cardio metabolic risk. This study highlighted high prevalence of vitamin D deficiency among Asian women with former GDM. Six months supplementation with 4000 IU of vitamin D3 safely restored the vitamin D level, improved basal pancreatic beta-cell function and ameliorated the metabolic state. There was no effect on markers of cardio metabolic risk. Further mechanistic studies exploring the role of vitamin D supplementation on glucose homeostasis among different ethnicities may be needed to better inform future recommendations for these women with former GDM at high risk of both hypovitaminosis D and future diabetes.     

The Relationship Between Serum 25-Hydroxyvitamin D and Glucose Homeostasis in Obese Children and Adolescents in Zhejiang,China

Objective: Evidence of the association between vitamin D, insulin resistance, and oral disposition index (oDI) in obese children and adolescents is limited. To fill this research gap, we measured serum 25-hydroxyvitamin D (25&lsqb;OH]D) levels in obese children and analyzed the relationship between serum 25(OH)D levels and glucose homeostasis.Methods: Altogether, 348 obese and 445 nonobese children and adolescents (age, 6 to 16 years) were enrolled in this study. Obese children were divided into 4 subgroups: normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and combined IFG and IGT (IFG+IGT) according to oral glucose tolerance test results. We measured serum 25(OH)D levels and calculated the homeostasis model assessment (HOMA) of insulin resistance (IR), the whole-body insulin sensitivity index (WBISI), and the disposition index.Results: The levels of 25(OH)D in the obese group were significantly lower than in the nonobese group; serum 25(OH)D level in the NGT subgroup was higher than those of the other 3 subgroups, and it was significantly inversely correlated with logHOMA-IR (r = -0.090; P = .045) and positively correlated with logWBISI and logHOMA-oDI (r = 0.091, P = .049; and r = 0.108, P = .046, respectively). Obese patients with vitamin D deficiency thus have a significantly higher risk of disturbances in glucose metabolism.Conclusion: 25(OH)D deficiency or insufficiency is quite common in obese children and adolescents in Zhejiang, China. Obese patients with 25(OH)D deficiency (<30 nmol/L) are shown to be at higher risk for abnormal glucose metabolism.Abbreviations: 25(OH)D = 25-hydroxyvitamin D ΔI₃₀/ΔG₃₀ = insulinogenic index BMI = body mass index CI = confidence interval HbA_1c = hemoglobin A_1c HOMA = homeostasis model assessment I_F = fasting insulin IFG = impaired fasting glucose IGT = impaired glucose tolerance IR = insulin resistance NGT = normal glucose tolerance oDI = oral disposition index OGTT = oral glucose tolerance test WBISI = whole-body insulin sensitivity index     

HbA1c Alone Is a Poor Indicator of Cardiometabolic Risk in Middle-Aged Subjects with Pre-Diabetes but Is Suitable for Type 2 Diabetes Diagnosis: A Cross-Sectional Study

Objectives

Glycated haemoglobin A_1c (HbA_1c) measurement is recommended as an alternative to fasting plasma glucose (FPG) for the diagnosis of pre-diabetes and type 2 diabetes. However, evidence suggests discordance between HbA_1c and FPG. In this study we examine a range of metabolic risk features, pro-inflammatory cytokines, acute-phase response proteins, coagulation factors and white blood cell counts to determine which assay more accurately identifies individuals at increased cardiometabolic risk.

Materials and Methods

This was a cross-sectional study involving a random sample of 2,047 men and women aged 46-73 years. Binary and multinomial logistic regression were employed to examine risk feature associations with pre-diabetes [either HbA_1c levels 5.7-6.4% (39-46 mmol/mol) or impaired FPG levels 5.6-6.9 mmol/l] and type 2 diabetes [either HbA_1c levels >6.5% (>48 mmol/mol) or FPG levels >7.0 mmol/l]. Receiver operating characteristic curve analysis was used to evaluate the ability of HbA_1c to discriminate pre-diabetes and diabetes defined by FPG.

Results

Stronger associations with diabetes-related phenotypes were observed in pre-diabetic subjects diagnosed by FPG compared to those detected by HbA_1c. Individuals with type 2 diabetes exhibited cardiometabolic profiles that were broadly similar according to diagnosis by either assay. Pre-diabetic participants classified by both assays displayed a more pro-inflammatory, pro-atherogenic, hypertensive and insulin resistant profile. Odds ratios of having three or more metabolic syndrome features were also noticeably increased (OR: 4.0, 95% CI: 2.8-5.8) when compared to subjects diagnosed by either HbA_1c (OR: 1.4, 95% CI: 1.2-1.8) or FPG (OR: 3.0, 95% CI: 1.7-5.1) separately.

Conclusions

In middle-aged Caucasian-Europeans, HbA_1c alone is a poor indicator of cardiometabolic risk but is suitable for diagnosing diabetes. Combined use of HbA_1c and FPG may be of additional benefit for detecting individuals at highest odds of type 2 diabetes development.     

2型糖尿病合并肺部感染患者维生素D的表达及其临床意义

目的:研究2型糖尿病合并肺部感染患者维生素D的表达及其临床意义。方法:以2017年6月～2018年12月我院收治的2型糖尿病患者160例为研究对象。将所有患者按照是否发生肺部感染分为观察组(发生肺部感染)61例与对照组(未发生肺部感染)99例。分别比较两组患者基本资料、维生素D水平、血糖相关指标水平以及T淋巴细胞亚群相关指标,并分析2型糖尿病合并肺部感染患者维生素D与血糖指标、T淋巴细胞亚群相关指标的相关性。结果:两组患者年龄、性别以及糖尿病病程等基本资料对比差异均无统计学意义(均P0.05)。观察组患者空腹血糖、糖化血红蛋白水平高于对照组,而25(OH)D水平低于对照组,差异均有统计学意义(均P0.05)。观察组患者CD3~+、CD4~+以及CD4~+/CD8~+低于对照组,差异有统计学意义(均P0.05)。经Spearman相关性分析可得:25(OH)D与空腹血糖、糖化血红蛋白水平均呈负相关关系,而与CD3~+、CD4~+以及CD4~+/CD8~+均呈正相关关系(均P0.05)。结论:2型糖尿病合并肺部感染患者维生素D水平下降,通过检测维生素D水平,有助于评估患者的血糖水平与免疫功能状况。     

Evolución clínica a 5 años desde el inicio de la insulinoterapia en pacientes con diabetes tipo 2 en España: resultados del estudio EDIN

ObjectivesThe primary study objective was to assess the proportion of patients with type 2 diabetes and an HbA_1c value ≤ 6.5% from the start of insulin therapy to five years later in the outpatient setting in Spain.Material and methodsThis was an observational, multicenter, naturalistic study with retrospective collection of clinical data. Investigators were endocrinologists or internal medicine specialists from all over Spain. During standard clinical care, patients started insulin therapy, which was continued for at least 5 years.ResultsThe clinical records of 405 patients were reviewed. The final analysis set included records from 346 patients. At baseline (start of insulin therapy), 51.2% of patients were female; mean (SD) age was 64.6 (9.0) years; body mass index, 29.8 (4-5) kg/m²; time since diagnosis, 8.8 (6.8) years; HbA_1c, 9.4% (1.5); fasting glucose, 223.7 (55.9) mg/dL; and mean 2-hour postprandial glucose, 293.6 (71.0) mg/dL. When insulin therapy was started, < 1.0% of patients had an HbA_1c value ≤ 6.5%. At 5 years, 10.3% of patients achieved the HbA_1c goal of ≤ 6.5% (mean, 7.72%). All glucose parameters (HbA_1c, fasting glucose, and 2-hour postprandial glucose) improved at 5 years as compared to values at the start of insulin therapy.ConclusionsGlucose parameters improved over time in patients with type 2 diabetes in this naturalistic study. However, blood glucose control exceeded the internationally recommended target values. These results therefore suggest that there is still some margin for improvement in outpatient care in Spain.     

Fructosamine Is a Useful Indicator of Hyperglycaemia and Glucose Control in Clinical and Epidemiological Studies – Cross-Sectional and Longitudinal Experience from the AMORIS Cohort

Context

Fructosamine is a glycemic biomarker which may be useful for indication and control of diabetes respectively.

Objective

The objective of the study was to evaluate fructosamine as an indicator of hyperglycaemia and glucose control in subjects with diabetes.

Design, Setting & Patients

From the AMORIS cohort, subjects with serum glucose, fructosamine and HbA_1c from the same examination were studied cross-sectionally and longitudinally (n = 10,987; 5,590 overnight-fasting). The guidelines of the American Diabetes Association were followed for classification of prediabetes and diabetes. Separate analyses were performed in patients with a newly detected or a known diagnosis of type 1 or type 2 diabetes respectively.

Results

All three biomarkers were strongly correlated. With regard to the association between fructosamine and HbA_1c Pearson linear correlation coefficients in the range of 0.67–0.75 were observed in fasting and non-fasting subjects with type 1 or type 2 diabetes. Analyses of glucose control in fasting patients with type 2 diabetes having all three biomarkers measured at three separate occasions within on average 290 days of the index examination showed similar trends over time for glucose, fructosamine and HbA_1c. Discrimination of subjects with and without diabetes across the range of fructosamine levels was good (area under curve (AUC) 0.91–0.95) and a fructosamine level of 2.5 mmol/L classified subjects to diabetes with a sensitivity of 61% and a specificity of 97%.

Conclusions

Fructosamine is closely associated with HbA_1c and glucose respectively and may be a useful biomarker of hyperglycaemia and glucose control in clinical and epidemiological studies.     

Ethnic disparity in hemoglobin A1c levels among normoglycemic offspring of parents with type 2 diabetes mellitus

ObjectiveTo investigate the racial/ethnic disparities in hemoglobin A_1c levels among nondiabetic persons with similar parental history of type 2 diabetes mellitus.MethodsWe studied a community-based sample of adult offspring of parents with type 2 diabetes mellitus. Measurements included anthropometry, hematology assessments, serial fasting plasma glucose, oral glucose tolerance testing, plasma insulin, hemoglobin A_1c, insulin sensitivity, and b-cell function, using a homeostasis model assessment.ResultsThe study included 302 participants (135 white, 167 black). Compared with white participants, black participants had lower fasting plasma glucose levels (91.9 ± 0.51 mg/dL vs 93.6 ± 0.50 mg/dL, P = .015), lower area under the curve of plasma glucose during oral glucose tolerance testing (P = <.001), higher body mass index (31.1 ± 0.61 kg/m² vs 28.5 ± 0.57 kg/m², P = <.001), and similar insulin sensitivity and b-cell function. Hemoglobin A_1c was higher in black participants than in white participants (5.68 ± 0.033% vs 5.45 ± 0.028%, P <.001). The absolute black-white difference in hemoglobin A_1c level of approximately 0.22% persisted after adjusting for age, hemoglobin, hematocrit, body mass index, waist circumference, fasting plasma glucose, glucose area under the curve, and other covariates.ConclusionsAmong healthy offspring of parents with type 2 diabetes mellitus in this study, African American participants had higher hemoglobin A_1c levels than white participants after adjusting for age, adiposity, blood glucose, and known variables. Thus, plasma glucose level is more valid than hemoglobin A_1c for diagnosing prediabetes or diabetes in black persons. (Endocr Pract. 2012; 18:356-362)     

Hemoglobin A1c and Arterial and Ventricular Stiffness in Older Adults

Objective

Arterial and ventricular stiffening are characteristics of diabetes and aging which confer significant morbidity and mortality; advanced glycation endproducts (AGE) are implicated in this stiffening pathophysiology. We examined the association between HbA_1c, an AGE, with arterial and ventricular stiffness measures in older individuals without diabetes.

Research Design & Methods

Baseline HbA_1c was measured in 830 participants free of diabetes defined by fasting glucose or medication use in the Cardiovascular Health Study, a population-based cohort study of adults aged ≥65 years. We performed cross-sectional analyses using baseline exam data including echocardiography, ankle and brachial blood pressure measurement, and carotid ultrasonography. We examined the adjusted associations between HbA_1c and multiple arterial and ventricular stiffness measures by linear regression models and compared these results to the association of fasting glucose (FG) with like measures.

Results

HbA_1c was correlated with fasting and 2-hour postload glucose levels (r = 0.21; p<0.001 for both) and positively associated with greater body-mass index and black race. In adjusted models, HbA_1c was not associated with any measure of arterial or ventricular stiffness, including pulse pressure (PP), carotid intima-media thickness, ankle-brachial index, end-arterial elastance, or left ventricular mass (LVM). FG levels were positively associated with systolic, diastolic and PP and LVM.

Conclusions

In this sample of older adults without diabetes, HbA_1c was not associated with arterial or ventricular stiffness measures, whereas FG levels were. The role of AGE in arterial and ventricular stiffness in older adults may be better assessed using alternate AGE markers.     

Dose- and Time-Dependent Association of Smoking and Its Cessation with Glycemic Control and Insulin Resistance in Male Patients with Type 2 Diabetes Mellitus: The Fukuoka Diabetes Registry

Objective

Cigarette smoking is an important modifiable risk factor for cardiovascular diseases. However, the effect of smoking and its cessation on glycemic control in diabetic patients has not been fully examined yet. The aim of the present study was to examine the association of smoking status with glycemic level and markers of insulin resistance and secretion in patients with type 2 diabetes mellitus.

Research Design and Methods

A total of 2,490 Japanese male patients with type 2 diabetes mellitus aged ≥20 years were divided according to smoking status, amount of cigarettes smoked and years since quitting. The associations with glycemic level and markers of insulin resistance and secretion were examined cross-sectionally.

Results

HbA_1c levels increased progressively with increases in both number of cigarettes per day and pack-years of cigarette smoking compared with never smokers (P for trend = 0.001 and <0.001, respectively), whereas fasting plasma glucose did not. On the other hand, HbA_1c, but not fasting plasma glucose, decreased linearly with increase in years after smoking cessation (P for trend <0.001). These graded relationships persisted significantly after controlling for the confounders, including total energy intake, current drinking, regular exercise, depressive symptoms, and BMI. In addition, a homeostasis model assessment of insulin resistance and high-sensitivity C-reactive protein also showed similar trends.

Conclusions

Smoking and its cessation showed dose- and time-dependent relationship with glycemic control and insulin resistance in patients with type 2 diabetes mellitus. These findings may highlight the importance of smoking cessation in the clinical management of diabetes mellitus.     

Pilot Study to Evaluate the Effect of Short-Term Improvement in Vitamin D Status on Glucose Tolerance in Patients With Type 2 Diabetes Mellitus

ObjectiveTo study the effect of improvement in vitamin D status on glucose tolerance in Asian Indian patients with moderately controlled type 2 diabetes mellitus (T2DM).MethodsThis randomized, double-blind, placebocontrolled pilot study was conducted in 28 Asian Indian patients with T2DM. Study participants were randomly assigned to a vitamin D-treated group (group D) or a placebo group (group P). Serum 25-hydroxyvitamin D, hemoglobin A1c, and serum fructosamine levels were measured, and an oral glucose tolerance test (OGTT) was performed in all patients at baseline and 4 weeks after intervention. During the OGTT, plasma glucose and serum insulin levels were measured at 0, 30, 60, 90, and 120 minutes. The unpaired t test was used to compare the groups at baseline and to compare the differences in changes from baseline to 4 weeks between the 2 study groups.ResultsGroup D and group P were similar with respect to their fasting plasma glucose and serum insulin concentrations, post-OGTT plasma glucose and serum insulin levels, and hemoglobin A1c and fructosamine values at baseline. Serum 25-hydroxyvitamin D levels increased significantly in group D at 4 weeks. No significant differences were found between the groups at baseline and 4 weeks with respect to serum fructosamine, fasting plasma glucose and serum insulin, post-OGTT plasma glucose and serum insulin levels, and homeostasis model assessment of insulin resistance.ConclusionIn this study, short-term improvement in vitamin D status was not associated with improvement in glucose tolerance, insulin secretion, or insulin sensitivity in Asian Indian patients with moderately controlled T2DM.(Endocr Pract. 2010;16:600-608)     

Markedly Low Hemoglobin A1c in a Patient with an Unusual Presentation of ß-Thalassemia Minor

ObjectiveTo describe very low hemoglobin A_1c levels in a patient with type 2 diabetes mellitus and an unusual presentation of β-thalassemia minor.MethodsWe present the clinical and laboratory findings of the study patient.ResultsA 64-year-old African American man with type 2 diabetes mellitus was referred to the endocrinology clinic with a hemoglobin A_1c level of 1.6% despite elevated blood glucose concentrations. A red blood cell survival study with chromium-51 revealed that he had a reduced erythrocyte life span less than 25% of normal. He also had a markedly elevated reticulocyte count ranging from 236 to 534 x 10³/μL (reference range, 25-75 x 103/μL). The laboratory findings, which are not characteristic of ß-thalassemia minor, could be the cause of the markedly low hemoglobin A_1c in this patient.ConclusionsAlthough rare, when associated with marked erythrocyte turnover, β-thalassemia minor can lead to a severe reduction in HbA_1c levels. In this scenario, glycemic control is best assessed by measuring fructosamine. (Endocr Pract. 2010;16:89-92)     

Association of Low Serum 25-Hydroxyvitamin D Levels in Pregnancy with Glucosehomeostasis and Obstetric And Newborn Outcomes

ObjectiveTo evaluate the association of maternal serum 25-hydroxyvitamin D (25[OH]D) status with glucose homeostasis and obstetric and newborn outcomes in women screened for gestational diabetes mellitus (GDM).MethodsConsecutive women were screened for GDM at 24 to 28 weeks’ gestation during the months of maximal sunlight exposure in Spain (June through September). Serum 25(OH)D levels and parameters of glucose homeostasis were measured. Outcomes of the delivery and newborn were collected.ResultsTwo hundred sixty-six women were screened. Vitamin D deficiency (25[OH]D < 20 ng/mL) was observed in 157 women (59%). We observed an inverse correlation between 25(OH)D levels and hemoglobin A_1c, homeostasis model assessment of insulin resistance, serum insulin, and fasting and 1-hour oral glucose tolerance test glucose levels (P <.001). With a 25(OH)D concentration less than 20 ng/mL, the odds ratios were 3.31 for premature birth (95% confidence interval, 1.52-7.19; P <.002) and 3.93 for cesarean delivery (95% confidence interval, 2.00-7.73; P <.001). A 25(OH)D concentration of 20 ng/mL had 79% sensitivity and 51% specificity for cesarean delivery and 80% sensitivity and 45% specificity for premature birth. The cutoffs with the best combination of sensitivity and specificity were 16 ng/mL for cesarean delivery (62.9% sensitivity and 61.2% specificity) and 14 ng/mL for premature birth (66.7% sensitivity and 71.0% specificity).ConclusionsIn the population we sampled, vitamin D deficiency is very common during pregnancy. Lower 25(OH)D levels are associated with disorders of glucose homeostasis and adverse obstetric and newborn outcomes.(Endocr Pract. 2012;18:676-684)     

Patient-Led Versus Physician-Led Titration of Insulin Glargine in Patients with Uncontrolled Type 2 Diabetes: A Randomized Multinational Atlas Study

ObjectiveSelf-adjustment of insulin dose is commonly practiced in Western patients with type 2 diabetes but is usually not performed in Asian patients. This multinational, 24-week, randomized study compared patient-led with physician-led titration of once-daily insulin glargine in Asian patients with uncontrolled type 2 diabetes who were on 2 oral glucose-lowering agents.MethodsPatient-led (n = 275) or physician-led (n = 277) subjects followed the same dose-titration algorithm guided by self-monitored fasting blood glucose (FBG; target, 110 mg/dL [6.1 mmol/L]). The primary endpoint was change in mean glycated hemoglobin (HbA_1c) at week 24 in the patient-led versus physician-led titration groups.ResultsPatient-led titration resulted in a significantly higher drop in HbA_1c value at 24 weeks when compared with physician-led titration (− 1.40% vs. − 1.25%; mean difference, − 0.15; 95% confidence interval, − 0.29 to 0.00; P = .043). Mean decrease in FBG was greatest in the patient-led group (− 2.85 mmol/L vs. − 2.48 mmol/L; P = .001). The improvements in HbA_1c and FBG were consistent across countries, with similar improvements in treatment satisfaction in both groups. Mean daily insulin dose was higher in the patient-led group (28.9 units vs. 22.2 units; P < .001). Target HbA_1c of < 7.0% without severe hypoglycemia was achieved in 40.0% and 32.9% in the patient-led and physician-led groups, respectively (P = .086). Severe hypoglycemia was not different in the 2 groups (0.7%), with an increase in nocturnal and symptomatic hypoglycemia in the patient-led arm.ConclusionPatient-led insulin glargine titration achieved near-target blood glucose levels in Asian patients with uncontrolled type 2 diabetes who were on 2 oral glucose-lowering drugs, demonstrating that Asian patients can self-uptitrate insulin dose effectively when guided. (Endocr Pract. 2015;21:143-157)     

Independent Association of HbA1c and Incident Cardiovascular Disease in People Without Diabetes

Recent studies have reported no association between elevated glycated hemoglobin (HbA_1c) and incident cardiovascular disease (CVD) among women without diabetes. This study describes associations between HbA_1c and new onset CVD in a representative adult population cohort. Assessment of participants in The North West Adelaide Health Study (NWAHS), a population study of randomly selected adults (age ≥18 years, n = 4,060), included measurement of height, weight, blood pressure, fasting lipids, glucose, and HbA_1c. A self‐completed questionnaire assessed doctor‐diagnosed diabetes, CVD and stroke, smoking status, and demographics. The cohort was followed for an average 3.5 years. Of the 2,913 adults free of diabetes at baseline and follow‐up, 94 (3.5%) reported new onset coronary heart disease (CHD) and/or stroke. Compared with those with an HbA_1c ≤5.0%, risk of new onset CVD was increased in those with HbA_1c 5.4–5.6% (odds ratio (OR) 2.5, 95% confidence interval (CI) 1.4, 4.6), and ≥5.7% (OR 1.9, 95% CI 1.1, 3.4), after adjustment for other risk factors. The association was stronger in women than men (P = 0.03), and attenuated to only a small degree by addition of impaired fasting glucose (IFG), hypertension, hypercholesterolemia, BMI, waist circumference, or smoking to the model. Elevated HbA_1c is related to new onset CVD over a relatively short follow‐up period in both men and women without diabetes and who do not develop diabetes, after adjustment for other major risk factors. Unlike previous studies, this relationship was not substantially attenuated by other traditional risk factors.     

Associations of serum 25-hydroxyvitamin D and components of the metabolic syndrome in obese adolescent females

Vitamin D deficiency may increase the risk for metabolic syndrome. We determined the relationship of serum 25‐hydroxyvitamin D (25(OH)D) with metabolic syndrome components in obese adolescent females and assessed whether vitamin D treatment corrects metabolic disturbances. Eighty postmenarchal adolescents (53 African American (AA) and 27 Caucasian American (CA)) were evaluated with blood pressures and fasting measurements of serum 25(OH)D, lipid profile, C‐reactive protein, alanine transaminases (ALTs) and aspartate transaminases followed by an oral glucose tolerance test. A subgroup (n = 14) of vitamin D deficient subjects were re‐evaluated following vitamin D treatment. Among all subjects, 25(OH)D was inversely associated with fasting glucose (r = ?0.28, P = 0.02) and positively associated with low‐density lipoprotein (LDL) cholesterol (r = 0.31, P = 0.008), independent of race and BMI. In analyses by race, adjusted for BMI, 25(OH)D was inversely associated with fasting insulin in CA (r = ?0.42, P = 0.03) but not AA (r = 0.11, P = 0.43) whereas 25(OH)D was positively associated with ALT in AA, but not CA (r = 0.29, P = 0.04 vs. r = ?0.21, P = 0.32). Fasting glucose improved in vitamin D treated subgroup (from 89.07 ± 8.3 mg/dl to 84.34 ± 8.4 mg/dl, P = 0.05). A trend toward improvement in fasting glucose remained after exclusion of four subjects whose serum 25(OH)D₂ did not improve following treatment (P = 0.12). In conclusion, serum 25(OH)D was inversely associated with fasting glucose, and vitamin D treatment had beneficial effects on fasting glucose. Relationships of 25(OH)D with fasting insulin and ALT were ethnic specific. The positive relationship with LDL and ALT were suggestive of possible adverse influences of vitamin D.     

Associations of type 2 diabetes with common variants in PPARD and the modifying effect of vitamin D among middle-aged and elderly Chinese

Background

Previous studies have identified that variants in peroxisome proliferator-activated receptor PPAR-δ (PPARD), a target gene of vitamin D, were significantly associated with fasting glucose and insulin sensitivity in European populations. This current study sought to determine (1) whether the genetic associations of PPARD variants with type 2 diabetes and its related traits could be replicated in Chinese Han population, and (2) whether the associations would be modified by the effect of vitamin D status.

Methods and Findings

We genotyped 9 tag single nucleotide polymorphisms (SNPs) that cover the gene of PPARD (rs2267664, rs6902123, rs3798343, rs2267665, rs2267668, rs2016520, rs2299869, rs1053049, and rs9658056) and tested their associations with type 2 diabetes risk and its related traits, including fasting glucose, insulin and HbA1c in 3,210 Chinese Hans. Among the 9 PPARD tag SNPs, rs6902123 was significantly associated with risk of type 2 diabetes (odds ratio 1.75 [95%CI 1.22–2.53]; P = 0.0025) and combined type 2 diabetes and impaired fasting glucose (IFG) (odds ratio 1.47 [95%CI 1.12–1.92]; P = 0.0054). The minor C allele of rs6902123 was associated with increased levels of fasting glucose (P = 0.0316) and HbA1c (P = 0.0180). In addition, we observed that vitamin D modified the effect of rs6902123 on HbA1c (P for interaction = 0.0347).

Conclusions/Significance

Our findings demonstrate that common variants in PPARD contribute to the risk of type 2 diabetes in Chinese Hans, and provided suggestive evidence of interaction between 25(OH)D levels and PPARD-rs6902123 on HbA1c.     

维生素D缺乏和2型糖尿病视网膜病变风险度的相关性研究

摘要 目的：是探讨维生素D缺乏与2型糖尿病（T2DM）患者视网膜病变（DR）发生风险度的关系。方法：选取2020年12月至2022年8月在新疆医科大学第二附属医院内分泌科住院的2型糖尿病患者作为研究对象。将209名患者根据眼底检查分为DR组（n=50）和正常眼底（NDR）组（n=159）。比较各组患者一般资料、实验室检查指标;采用Spearman分析法分析病程、FBG、HbAlC、25(OH)D与DR的相关性,采用Pearson分析居住地（城镇）、与维生素D缺乏、SBP与DR的相关性,采用Logistics回归分析DR发生的影响因素,比较各组患者维生素D缺乏、病程、FBG、HbA1c及25(OH)D对DR的预测价值。结果：DR组的居住地（农村）、FBG、HbA1c、病程等均大于NDR组,25(OH)D水平低于NDR组,DR组维生素D缺乏率大于NDR组,差异有统计学意义（P＜0.05）。Pearson相关性分析结果表明DR与居住地（城镇）呈负相关（P＜0.05）,与SBP、维生素D缺乏呈正相关（P＜0.05）;Spearman相关分析表明DR与25(OH)D呈负相关（P＜0.05）,与病程、空腹血糖和糖化血红蛋白等呈正相关（P＜0.05）。Logistic回归分析结果显示,维生素D缺乏、病程、FBG、HbA1c为DR的独立危险因素（P＜0.05）,维生素D缺乏的T2DM患者DR发病风险是维生素D不缺乏者的22.019倍（OR=22.019,95%CL 2.119~228.771,P＜0.05）。受试者工作特征（ROC）曲线分析显示,病程、FBG、HbA1c、25(OH)D作为联合变量可有效预测DR,ROC曲线下面积为0.924。结论：25(OH)D与DR呈负相关,维生素D缺乏可能与T2DM患者DR的发生有关。     

Vitamin D insufficiency in diabetic retinopathy

ObjectiveTo assess the relationship between vitamin D status and diabetic retinopathy.MethodsA clinic-based, cross-sectional study was conducted at Emory University, Atlanta, Georgia. Overall, 221 patients were classified into 5 groups based on diabetes status and retinopathy findings: no diabetes or ocular disease (n = 47), no diabetes with ocular disease (n = 51), diabetes with no background diabetic retinopathy (n = 41), nonproliferative diabetic retinopathy (n = 40), and proliferative diabetic retinopathy (PDR) (n = 42). Patients with type 1 diabetes and those taking > 1,000 IU of vitamin D daily were excluded from the analyses. Study subjects underwent dilated funduscopic examination and were tested for hemoglobin A_1c, serum creatinine, and 25-hydroxyvitamin D [25(OH)D] levels between December 2009 and March 2010.ResultsAmong the study groups, there was no statistically significant difference in age, race, sex, or multivitamin use. Patients with diabetes had lower 25(OH)D levels than did those without diabetes (22.9 ng/mL versus 30.3 ng/mL, respectively; P < .001). The mean 25(OH)D levels, stratified by group, were as follows: no diabetes or ocular disease = 31.9 ng/mL; no diabetes with ocular disease = 28.8 ng/mL; no background diabetic retinopathy = 24.3 ng/ mL; nonproliferative diabetic retinopathy = 23.6 ng/mL; and PDR = 21.1 ng/mL. Univariate analysis of the 25(OH) D levels demonstrated statistically significant differences on the basis of study groups, race, body mass index, multivitamin use, hemoglobin A_1c, serum creatinine level, and estimated glomerular filtration rate. In a multivariate linear regression model with all potential confounders, only multivitamin use remained significant (P < .001).ConclusionThis study suggests that patients with diabetes, especially those with PDR, have lower 25(OH)D levels than those without diabetes. (Endocr Pract. 2012; 18:185-193)