The single-point insulin sensitivity estimator (SPISE) index is a strong predictor of abnormal glucose metabolism in overweight/obese children: a long-term follow-up study.

PURPOSE: To investigate the relationship between the single-point insulin sensitivity estimator (SPISE) index, an insulin sensitivity indicator validated in adolescents and adults, and metabolic profile in overweight/obese children, and to evaluate whether basal SPISE is predictive of impaired glucose regulation (IGR) development later in life. METHODS: The SPISE index (= 600 × HDL0.185/Triglycerides0.2 × BMI1.338) was calculated in 909 overweight/obese children undergoing metabolic evaluations at University of Cagliari, Italy, and in 99 normal-weight, age-, sex-comparable children, selected as a reference group, together with other insulin-derived indicators of insulin sensitivity/resistance. 200 overweight/obese children were followed-up for 6.5 [3.5-10] years, data were used for longitudinal retrospective investigations. RESULTS: At baseline, 96/909 (11%) overweight/obese children had IGR; in this subgroup, SPISE was significantly lower than in normo-glycaemic youths (6.3 ± 1.7 vs. 7 ± 1.6, p < 0.001). The SPISE index correlated positively with the insulin sensitivity index (ISI) and the disposition index (DI), negatively with age, blood pressure, HOMA-IR, basal and 120 min blood glucose and insulin (all p values < 0.001). A correlation between SPISE, HOMA-IR and ISI was also reported in normal-weight children. At the 6.5-year follow-up, lower basal SPISE-but not ISI or HOMA-IR-was an independent predictor of IGR development (OR = 3.89(1.65-9.13), p = 0.002; AUROC: 0.82(0.72-0.92), p < 0.001). CONCLUSION: In children, low SPISE index is significantly associated with metabolic abnormalities and predicts the development of IGR in life.

Sick fat: the good and the bad of old and new circulating markers of adipose tissue inflammation.

Adipose tissue (AT) is one of the largest endocrine organs contributing to metabolic homeostasis. The functional pleiotropism of AT depends on its ability to secrete a large number of hormones, cytokines, extracellular matrix proteins and growth factors, all influencing many local and systemic physiological and pathophysiological processes. In condition of chronic positive energy balance, adipocyte expansion, hypoxia, apoptosis and stress all lead to AT inflammation and dysfunction, and it has been demonstrated that this sick fat is a main risk factor for many metabolic disorders, such as type 2 diabetes mellitus, fatty liver, cardiovascular disease and cancer. AT dysfunction is tightly associated with aberrant secretion of bioactive peptides, the adipocytokines, and their blood concentrations often reflect the expression in the AT. Despite the existence of an association between AT dysfunction and systemic pro-inflammatory state, most of the circulating molecules detectable in obese and dysmetabolic individuals do not identify specifically the condition of sick fat. Based on this premise, this review provides a concise overview of "classic" and novel promising adipocytokines associated with AT inflammation and discusses possible critical approaches to their interpretation in clinical practice.

Impaired bone matrix glycoprotein pattern is associated with increased cardio-metabolic risk profile in patients with type 2 diabetes mellitus.

PURPOSE: Osteopontin (OPN), osteoprotegerin (OPG) and osteocalcin (OC) are matrix glycoproteins which mediate bone mineralization; moreover, their effects on glucose/insulin homeostasis have recently been demonstrated. Higher circulating OPN and OPG levels have been associated with the presence of insulin resistance, atherosclerosis and coronary heart disease. No data are available on contextual changes of these markers in type 2 diabetes mellitus (T2DM). Therefore, aims of this study were to evaluate serum OPN, OPG and OC levels in T2DM patients and their clinical correlates. METHODS: We recruited 83 consecutive T2DM patients referring to our diabetes outpatient clinics at Sapienza, University of Rome, and 71 non-diabetic sex and age-comparable subjects as a control group. Study population underwent metabolic characterization and carotid ultrasound for intima-media thickness measurement. Plasma OPN, OPG and OC were measured by MILLIPLEX Multiplex Assays Luminex. RESULTS: T2DM patients had significantly higher circulating OPN and OPG levels than controls (14.3 ± 13.6 vs 10.6 ± 13.7 ng/ml p < 0.001, 0.70 ± 0.60 vs 0.54 ± 4.1 ng/ml, p = 0.02) while OC levels were similar in the two cohorts (6.35 ± 5.8 vs 7.80 ± 7.0 ng/ml, p = n.s). OPN and OPG positively correlated with greater systolic blood pressure (SBP) values, HOMA-IR and HOMA-ß, and with the presence of dyslipidemia and carotid atherosclerosis. The association between greater OPN and OPG levels and SBP was independent from possible confounders (both p = 0.01). CONCLUSIONS: Circulating OPN and OPG levels are increased in T2DM patients and identify a particularly unfavourable metabolic profile, mostly expressed by higher SBP. Bone peptides may represent novel markers of vascular stress and accelerated atherosclerosis in diabetes, constituting a possible tool for cardiovascular risk stratification in diabetes.

Procollagen-III peptide identifies adipose tissue-associated inflammation in type 2 diabetes with or without nonalcoholic liver disease.

BACKGROUND: Procollagen-III peptide (PIIINP) is a marker of fibrosis associated with increased cardiometabolic risk and progression of chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD) and steatohepatitis; its association with type 2 diabetes mellitus (T2DM) has not been elucidated yet. The aim of this study was to investigate the relationship among circulating PIIINP levels, metabolic traits, and body fat distribution in subjects with T2DM with or without NAFLD. METHODS: Data from 62 T2DM subjects recruited in our diabetes outpatient clinics at Sapienza University of Rome, Italy, were analysed. Participants underwent metabolic and inflammatory profiling (CRP, TNFα, IL-6, IL-8, WISP1, and adiponectin) and magnetic resonance imaging for diagnosing NAFLD on the basis of hepatic fat fraction (≥5.5%) and quantifying visceral and subcutaneous adipose tissue (AT) areas. Serum PIIINP was measured by human-PIIINP ELISA kits. RESULTS: Higher PIIINP levels correlated with greater BMI and visceral AT area and were associated with systemic signatures of AT-associated inflammation-ie, higher WISP-1, IL-8, and lower adiponectin levels; conversely, PIIINP did not differ significantly between T2DM patients with or without NAFLD and were not associated with hepatic fat fraction, Fatty Liver Index, FIB-4, or transaminases. CONCLUSIONS: Elevated circulating PIIINP levels specifically identify T2DM individuals with AT expansion and systemic proinflammatory profile suggestive for AT dysfunction; our results point toward a new role of PIIINP as a marker of fibroinflammation in dysmetabolic conditions, likely related to AT expansion.

Association between systemic leptin and neurotensin concentration in adult individuals with and without type 2 diabetes mellitus.

PURPOSE: Leptin is an adipokine which regulates appetite and energy balance through a mechanism partially mediated by neurotensin (NT) in central nervous system. Besides acting as a neurotransmitter, NT is expressed in human intestine where it promotes fat absorption and its circulating levels associate with obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease. Whether a relation exists between circulating leptin and NT levels has not been investigated yet. The aim of this study was to test the hypothesis of an association between plasma leptin and NT concentration in adults with or without T2DM. METHODS: We recruited a population of 72 subjects (M/F: 39/33; age: 49.5 ± 10.6 years; BMI: 26.5 ± 4.7 kg/m2) including individuals with T2DM (n = 32) referring to our Diabetes Outpatient Clinics, Sapienza University of Rome, and healthy controls. Study participants underwent metabolic characterization; plasma leptin was measured by MILLIPLEX, Luminex, and proneurotensin (proNT), a stable precursor of NT, by chemiluminometric sandwich immunoassay. RESULTS: Circulating median (25°-75°) leptin levels were 2.75 (1.27-4.93) ng/mL and did not differ between T2DM and non-diabetic subjects. Leptin concentration directly correlated with proNT (r = 0.41; p = 0.015); higher leptin levels were also associated with age, male gender, obesity, higher HOMA-IR, systolic blood pressure and C-reactive protein. Belonging to the highest pro-NT quartile correlated with greater leptin levels independent of age, gender and other confounders (r2 = 0.82, p = 0.02). CONCLUSIONS: Circulating leptin is associated with higher proNT levels independent of diabetes, obesity and metabolic syndrome components; besides its effects on central leptin signaling, NT may influence energy balance by modulating circulating leptin concentration likely through a mechanism involving gut fat absorption.

Presence of diabetes-specific autoimmunity in women with gestational diabetes mellitus (GDM) predicts impaired glucose regulation at follow-up.

PURPOSE: Gestational diabetes mellitus (GDM) is the most frequent complication of pregnancy; around 10% of GDM cases may be determined by autoimmunity, and our aims were to establish the role of autoimmunity in a population of Sardinian women affected by GDM, to find predictive factors for autoimmune GDM, and to determine type 1 diabetes (T1D) auto-antibodies (Aabs) together with glucose tolerance after a mean 21.2 months of follow-up. METHODS: We consecutively recruited 143 women affected by GDM and 60 without GDM; clinical data and pregnancy outcomes were obtained by outpatient visit or phone recall. T1D auto-antibodies GADA, IA2-A, IAA, ZnT8-A were measured in the whole population at baseline, and in the Aab-positive women at follow-up. RESULTS: The overall prevalence of autoimmunity was 6.4% (13/203). No significant difference was found in the prevalence of auto-antibodies between GDM (5.6%) and control (8.3%) women, neither in antibody titres. Highest titres for GADA and ZnT8-A were observed in the control group; no phenotypic factors were predictive for autoimmune GDM. Diabetes-related autoantibodies were still present in all the GDM women at follow-up, and their presence was associated with a 2.65 (p < 0.0016) relative risk (RR) of glucose impairment. CONCLUSION: We observed a low prevalence (5.6%) of diabetes-related autoimmunity in our GDM cohort, consistent with the prevalence reported in previous studies. It was not possible to uncover features predictive of autoimmune GDM. However, given the significant risk of a persistent impaired glycemic regulation at follow-up, it is advisable to control for glucose tolerance in GDM women with diabetes-related autoimmunity.

The vitamin D receptor (VDR) gene rs11568820 variant is associated with type 2 diabetes and impaired insulin secretion in Italian adult subjects, and associates with increased cardio-metabolic risk in children.

BACKGROUND AND AIMS: 1α,25-dihydroxyvitamin-D3, the biologically active vitamin D, plays a central role in several metabolic pathways through the binding to the vitamin D receptor (VDR). VDR has been shown to be involved in cardiovascular diseases, cancer, autoimmunity and type 2 diabetes mellitus (T2DM). Several polymorphisms in the VDR gene have been described. Among these, the rs11568820 G-to-A nucleotide substitution was found to be functional, modulating the transcription of the VDR gene. Objective of this study was to perform an association study between rs11568820 polymorphism and T2DM in a cohort of Italian adults with T2DM and in non-diabetic controls. To add further insight into the role of VDR gene we explored whether this association begins early in life in overweight/obese children, or becomes manifest only in adulthood. METHODS AND RESULTS: As many as 1788 adults and 878 children were genotyped for the rs11568820 polymorphism. All participants underwent oral glucose tolerance tests (OGTT), with measurement of glucose and insulin levels. Indices of insulin-resistance and secretion were also calculated. The AA genotype was significantly more frequent in adults with T2DM compared to controls (7.5% vs. 4.6%, P = 0.037), and conferred a higher risk of T2DM (ORHom = 1.69C.I. = [1.13-2.53], P = 0.011). In the adult cohort, rs11568820 was also associated with reduced indices of ß-cell insulin secretion. In children, the AA genotype was associated with 2 h high-normal glucose, a marker of cardio-metabolic risk. CONCLUSIONS: Our study demonstrates for the first time that VDR gene AA carriers have higher risk of T2DM and impaired insulin secretion. In children, the association between AA homozygous and high-normal 2h glucose suggests that mild alterations associated with this genotype may appear early in life.

The "Sapienza University Mortality and Morbidity Event Rate (SUMMER) study in diabetes": Study protocol.

BACKGROUND AND AIMS: The rate of mortality in diabetic patients, especially of cardiovascular origin, is about twice as much that of nondiabetic individuals. Thus, the pathogenic factors shaping the risk of mortality in such patients must be unraveled in order to target intensive prevention and treatment strategies. The "Sapienza University Mortality and Morbidity Event Rate (SUMMER) study in diabetes" is aimed at identifying new molecular promoters of mortality and major vascular events in patients with type 2 diabetes mellitus (T2DM). METHODS/DESIGN: The "SUMMER study in diabetes" is an observational, prospective, and collaborative study conducted on at least 5000 consecutive patients with T2DM, recruited from several diabetes clinics of Central-Southern Italy and followed up for a minimum of 5 years. The primary outcome is all-cause mortality; the secondary outcomes are cardiovascular mortality, acute myocardial infarction, stroke, and dialysis. A biobank will be created for genomic, transcriptomic, and metabolomic analysis, in order to unravel new molecular predictors of mortality and vascular morbidity. DISCUSSION: The "SUMMER study in diabetes" is aimed at identifying new molecular promoters of mortality and major vascular events in patients with T2DM. These novel pathogenic factors will most likely be instrumental in unraveling new pathways underlying such dramatic events. In addition, they will also be used as additional markers to increase the performance of the already existing risk-scoring models for predicting the above-mentioned outcomes in T2DM, as well as for setting up new preventive and treatment strategies, possibly tailored to specific pathogenic backgrounds. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02311244; URL https://clinicaltrials.gov/ct2/show/NCT02311244?term=SUMMER&rank=5.

Analysis of prognostic factors in COVID-19 hospitalized patients: an Italian single-center case-control study.

OBJECTIVE: COVID-19 clinical presentation ranges from asymptomatic infection to an inflammatory cytokine storm with multi-organ failure and fatal outcomes. The identification of high-risk patients for severe disease is crucial to plan an early treatment and intensive follow-up. We aimed to investigate negative prognostic factors in a group of patients hospitalized for COVID-19. PATIENTS AND METHODS: 181 patients (90 men and 91 women, mean age 66.56 ± 13.53 years) were enrolled. Each patient received a work-up including medical history, clinical examination, arterial blood gas analysis, laboratory blood tests, feasible ventilatory support required during hospital stay, intensive care setting required, duration of illness and length of hospital stay (>or<25 days). For the assessment of the severity of COVID-19, three main indicators were considered: 1) the intensive care unit (ICU) admission 2) the hospitalization length >25 days; 3) the need of non-invasive ventilation (NIV). RESULTS: The independent risk factor associated with the ICU admission were lactic dehydrogenase elevation (p=0.046), C reactive protein elevation (p=0.014) at hospital admission and direct oral anticoagulant home therapy (p=0.048); for hospital length >25 days: early corticosteroid therapy (p=0.035); for NIV treatment: ferritin elevation at hospital admission (p=0.006). CONCLUSIONS: The presence of the above factors may be useful to identify patients at high risk of developing a severe COVID-19 that need an early treatment and intensive follow-up.

High prevalence of capillary abnormalities in patients with diabetes and association with retinopathy.

AIMS: To investigate the presence of capillary abnormalities in patients with Type 1 and Type 2 diabetes using nailfold videocapillaroscopy and to evaluate the possible correlation with the typical diabetes mellitus microangiopathic lesions detectable in retinal blood vessels. METHODS: Forty-nine patients with diabetes mellitus (21 with Type 1 and 28 with Type 2 diabetes) and 39 subjects without diabetes were enrolled. Ophthalmoscopy was performed on all patients and was followed by retinal fluorangiography when indicated. Subjects underwent nailfold videocapillaroscopy to evaluate density, length, morphology and distribution of capillary loops, presence of ectasia, microbleedings and blood flow modifications. A score (0-3) was applied to quantify features of nailfold videocapillaroscopy. RESULTS: Subjects with diabetes showed a significantly increased (P = 0.0001) nailfold videocapillaroscopy score and significantly greater alterations of capillary length (P = 0.004), distribution (P = 0.02), morphology (P = 0.0001), density (P = 0.02) and flux (P = 0.004), as well as presence of ectasic loops (P = 0.009) and of oedema/exudates (P = 0.03) compared with control subjects. In addition, patients with Type 1 diabetes had a significantly higher score (P = 0.01) and greater morphologic alterations (P = 0.03) compared with subjects with Type 2 diabetes. Nailfold videocapillaroscopy score also showed a positive correlation with retinopathy, detected by both ophthalmoscopy (P = 0.0001) and fluorangiography (P = 0.02), independently from sex, age, type of diabetes and all potential confounders. Moreover, nailfold videocapillaroscopy was capable of identifying alterations in almost 50% of patients with diabetes without retinopathy. CONCLUSIONS: A high prevalence of nailfold capillary changes is detected in patients with diabetes using nailfold videocapillaroscopy. These abnormalities tightly correlate with retinal damage and may be expression of a generalized microvessel involvement in both Type 1 and Type 2 diabetes.

Subclinical vascular alterations in young adults with type 1 diabetes detected by arterial tonometry.

BACKGROUND: Diabetes mellitus is characterized by a very high prevalence of atherosclerotic disease. Aims of this study were to determine arterial compliance parameters in type 1 diabetes (T1D) patients as an expression of early pre-clinical endothelial dysfunction and to evaluate the impact of glucose exposure parameters such as the duration of diabetes and glycosylated haemoglobin (HbA(1c)) on the risk of developing alterations in vascular compliance. METHODS: 23 patients with uncomplicated type 1 diabetes (mean age: 32.78 +/- 9.06 years, mean disease duration: 10.78 +/- 7.51 years, mean HbA(1c) levels: 7.7 +/- 1.9) and 26 age- and sex-matched healthy subjects (mean age: 32.3 +/- 8.51 years) were recruited. In these subjects, we evaluated arterial compliance by calibrated tonometry (HDI/Pulsewave() CR-2000). Parameters included the following: large artery elasticity (C1), small artery elasticity (C2), systemic vascular resistance (SVR) and total vascular impedance (TVI). RESULTS: Patients with longer duration of T1D (>10 years) showed significant alterations in C2 (4.97 +/- 2.7 mL/mmHg x 100) and in SVR (1464.67 +/- 169.16 dina x s x cm(-5)) when compared with both healthy individuals (C2: 8.28 +/- 2.67 mL/mmHg x 100, p = 0.001; SVR: 1180.58 +/- 151.55 dina x s x cm(-5), p = 0.01) and patients with recent-onset disease (

ANGPTL4 gene E40K variation protects against obesity-associated dyslipidemia in participants with obesity.

OBJECTIVE: ANGPTL4 inhibits lipoprotein lipase in adipose tissue, regulating plasma triglycerides levels. In persons with obesity plasma ANGPTL4 levels have been positively correlated with body fat mass, TG levels and low HDL. A loss-of-function E40K mutation in ANGPTL4 prevents LPL inhibition, resulting in lower TGs and higher HDLc in the general population. Since obesity determines metabolic alterations and consequently is a major risk factor for cardiovascular disease, the aim was to explore if obesity-related metabolic abnormalities are modified by the ANGPTL4-E40K mutation. METHODS: ANGPTL4-E40K was screened in 1206 Italian participants, of which 863 (71.5%) with obesity. All subjects without diabetes underwent OGTT with calculation of indices of insulin-sensitivity. RESULTS: Participants with obesity carrying the E40K variant had significantly lower TG (p = 0.001) and higher HDLc levels (p = 0.024). Also in the whole population low TGs and high HDLc were confirmed in E40K carriers. In the obese subpopulation it was observed that almost all E40K carriers were within the lowest quartile of TGs (p = 1.1 × 10-9). E40K had no substantial effect of on glucose metabolism. Finally, none of the obese E40K carriers had T2D, and together with the favourable lipid profile, they resemble a metabolically healthy obese (MHO) phenotype, compared to 38% of E40E wild-type obese that had diabetes and/or dyslipidaemia (p = 0.0106). CONCLUSIONS: In participants with obesity the ANGPTL4-E40K variant protects against dyslipidemia. The phenotype of obese E40K carriers is that of a patient with obesity without metabolic alterations, similar to the phenotype described as metabolic healthy obesity.

Circulating IL-8 levels are increased in patients with type 2 diabetes and associated with worse inflammatory and cardiometabolic profile.

AIMS: Interleukin-8 (IL-8) is a chemokine involved in systemic immunity, macrophages infiltration and activation in adipose tissue and may play a significant role in the pathogenesis of type 2 diabetes (T2D) and atherosclerosis. Aims of this study were to evaluate circulating IL-8 levels in adult patients with T2D in comparison with non-diabetic subjects and to describe clinical and biochemical correlates of IL-8 concentration. METHODS: For this cross-sectional study, we enrolled 79 consecutive T2D individuals referring to our diabetes outpatient clinics at Sapienza University of Rome, and 37 sex, age and BMI comparable non-diabetic subjects as a control group. Clinical parameters and medical history were recorded; fasting blood sampling was performed for biochemistry and for measuring serum IL-8, IL-6, TNF-α, CRP, adiponectin and 25(OH)vitamin D [25(OH)D] levels. RESULTS: Patients with T2D exhibited significantly higher serum IL-8 levels than non-diabetic subjects (69.27 ± 112.83 vs. 16.03 ± 24.27 pg/mL, p < 0.001). In diabetic patients, increased IL-8 concentration correlated with higher IL-6 (p < 0.001), TNF-α (p = 0.02), FBG (p = 0.035), HbA1c (p = 0.04) and LDL-C (p = 0.04) and with lower adiponectin (p = 0.02) and 25(OH)D (p = 0.003) concentrations. CONCLUSIONS: Patients with T2D display a marked elevation of circulating IL-8 levels which identify subjects with worse inflammatory, glycometabolic and lipid profile and lower vitamin D levels. Further studies are warranted for evaluating a possible role of IL-8 as a novel marker for risk stratification in T2D patients.

Dipeptidyl peptidase-4 inhibitors and bone metabolism: is vitamin D the link?

AIMS: Dipeptidyl peptidase-4 inhibitors (DPP4-Is) represent a promising class of agents for type 2 diabetes treatment. Experimental models and clinical studies have reported positive effects of DPP4-Is on bone; however, how DPP4-Is positively impact bone homeostasis in humans remains an unanswered question. Aim of this study investigated the relationship between treatment with DPP4-Is and vitamin D balance in patients with type 2 diabetes. METHODS: This is a cross-sectional study. A total of 295 consecutive individuals with type 2 diabetes referring to our diabetes outpatient clinics were enrolled; among them, 53 % were in treatment with DPP4-Is. Metabolic profile and routine biochemistry were assessed by standard methods; serum 25(OH) vitamin D levels [25(OH)D] were measured by colorimetric method (LAISON, DiaSorin). RESULTS: DPP4-Is-treated participants had significantly higher serum 25(OH)D levels then those undertaking other antidiabetic therapies (18.4 ± 10.7 vs. 14.9 ± 8.6 ng/ml, p = 0.004); this association persisted after adjusting for all major confounders. Increased 25(OH)D concentrations also correlated with the duration of DPP4-Is treatment and with a stronger DPP4 inhibitory activity. CONCLUSIONS: DPP4-Is treatment is associated with improved vitamin D balance in people with type 2 diabetes; our findings suggest that vitamin D may underlie the link between DPP4-Is and bone metabolism.

Increased circulating osteopontin levels in adult patients with type 1 diabetes mellitus and association with dysmetabolic profile.

OBJECTIVE: Osteopontin (OPN) is a sialoprotein implicated in different immunity and metabolic pathways. Capable of activating dendritic cells and inducing Th1-Th17-mediated tissue damage, OPN plays a significant role in the development/progression of several autoimmune diseases; interestingly, it was also shown that OPN participates in the acute pancreatic islets response to experimentally induced diabetes in non-obese diabetic (NOD) mice. Furthermore, OPN promotes adipose tissue dysfunction, systemic inflammation and insulin resistance. Our aims of this study were to evaluate circulating OPN levels in adult patients with type 1 diabetes mellitus (T1DM) compared to non-diabetic control participants and to unravel clinical and biochemical correlates of OPN concentration. DESIGN: Case-control study. METHODS: We enrolled 54 consecutive T1DM patients referred to our diabetes outpatient clinic at Sapienza University of Rome and 52 healthy sex and age-comparable controls. The study population underwent clinical evaluation, blood sampling for biochemistry and complete screening for diabetes complications. Serum OPN levels were measured by MILLIPLEX Multiplex Assays Luminex. RESULTS: T1DM patients had significantly higher serum OPN levels than controls (17.2±12.9 vs 10.5±11.6 mg/ml, P=0.009). OPN levels correlated with T1DM, higher blood pressure, BMI, creatinine, γ-GT, ALP and lower HDL; the association between high OPN levels and T1DM was independent from all confounders. No correlation was shown between OPN and HbA1c, C-peptide, insulin requirement, co-medications and diabetes duration. CONCLUSIONS: This study demonstrates for the first time in a case-control study that adults with T1DM have increased serum OPN levels, and that higher OPN concentrations are associated with an unfavorable metabolic profile in these patients.

TSH levels are associated with vitamin D status and seasonality in an adult population of euthyroid adults.

A circannual periodicity in thyrotropin (TSH) secretion has been reported but the causes of these phenomenon are still undefined. Vitamin D exerts a direct influence on pituitary axes including the hypothalamus-pituitary-thyroid axis. Aims of the present study were to investigate the presence of a seasonal variability of TSH secretion and to study the association between vitamin D status and TSH levels in a population of euthyroid adults. For this purpose, we recruited 294 euthyroid adults (M/F 133/161, 48.5 ± 12.4 years). Study participants underwent clinical examination and routine biochemistry assessment. Vitamin D deficiency was diagnosed for serum 25(OH) vitamin D <25 nmol/l. Significantly higher TSH levels were found in subjects who underwent blood sampling during the Autumn-Winter compared with individuals evaluated in Spring-Summer (2.3 ± 1.3 vs. 1.8 ± 1.1 µIU/ml, p = 0.03). Vitamin D deficiency was strongly associated with higher TSH levels (p = 0.01) after adjusting for sex, age, and sample's season. Although vitamin D deficiency was also associated with metabolic syndrome and its components, the association between TSH levels and vitamin D status persisted also considering these confounders. These data reveal the occurrence of seasonal variability of serum TSH concentration in euthyroid subjects and provide evidence for the first time that an association exists between vitamin D status and serum TSH levels.