Silvia Della Casa

25-Hydroxyvitamin D Concentration Correlates With Insulin-Sensitivity and BMI in Obesity

The prevalence of hypovitaminosis D is high among obese subjects. Further, low 25‐hydroxyvitamin D (25(OH)D) concentration has been postulated to be a risk factor for type 2 diabetes, although its relation with insulin‐sensitivity is not well investigated. Thus, we aimed to investigate the relationship between 25(OH)D concentration and insulin‐sensitivity, using the glucose clamp technique. In total, 39 subjects with no known history of diabetes mellitus were recruited. The association of 25(OH)D concentration with insulin‐sensitivity was evaluated by hyperinsulinemic euglycemic clamp. Subjects with low 25(OH)D (<50 nmol/l) had higher BMI (P = 0.048), parathyroid hormone (PTH) (P = 0.040), total cholesterol (P = 0.012), low‐density lipoprotein (LDL) cholesterol (P = 0.044), triglycerides (P = 0.048), and lower insulin‐sensitivity as evaluated by clamp study (P = 0.047). There was significant correlation between 25(OH)D and BMI (r = −0.58; P = 0.01), PTH (r = −0.44; P < 0.01), insulin‐sensitivity (r = 0.43; P < 0.01), total (r = −0.34; P = 0.030) and LDL (r = −0.40; P = 0.023) (but not high‐density lipoprotein (HDL)) cholesterol, and triglycerides (r = 0.45; P = 0.01). Multivariate analysis using 25(OH)D concentration, BMI, insulin‐sensitivity, HDL cholesterol, LDL cholesterol, total cholesterol, and triglycerides, as the cofactors was performed. BMI was found to be the most powerful predictor of 25(OH)D concentration (r = −0.52; P < 0.01), whereas insulin‐sensitivity was not significant. Our study suggested that there is no cause–effect relationship between vitamin D and insulin‐sensitivity. In obesity, both low 25(OH)D concentration and insulin‐resistance appear to be dependent on the increased body size.

Long-term follow-up in adrenal incidentalomas: an Italian multicenter study

CONTEXT The long-term consequences of subclinical hypercortisolism (SH) in patients with adrenal incidentalomas (AIs) are unknown. SETTING AND PATIENTS In this retrospective multicentric study, 206 AI patients with a ≥5-year follow-up (median, 72.3 mo; range, 60-186 mo) were enrolled. INTERVENTION AND MAIN OUTCOME MEASURES Adrenocortical function, adenoma size, metabolic changes, and incident cardiovascular events (CVEs) were assessed. We diagnosed SH in 11.6% of patients in the presence of cortisol after a 1 mg-dexamethasone suppression test >5 μg/dL (138 nmol/L) or at least two of the following: low ACTH, increased urinary free cortisol, and 1 mg-dexamethasone suppression test >3 μg/dL (83 nmol/L). RESULTS At baseline, age and the prevalence of CVEs and type 2 diabetes mellitus were higher in patients with SH than in patients without SH (62.2 ± 11 y vs 58.5 ± 10 y; 20.5 vs 6%; and 33.3 vs 16.8%, respectively; P < .05). SH and type 2 diabetes mellitus were associated with prevalent CVEs (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.1-9.0; and OR, 2.0; 95% CI, 1.2-3.3, respectively), regardless of age. At the end of the follow-up, SH was diagnosed in 15 patients who were without SH at baseline. An adenoma size >2.4 cm was associated with the risk of developing SH (sensitivity, 73.3%; specificity, 60.5%; P = .014). Weight, glycemic, lipidic, and blood pressure control worsened in 26, 25, 13, and 34% of patients, respectively. A new CVE occurred in 22 patients. SH was associated with the worsening of at least two metabolic parameters (OR, 3.32; 95% CI, 1.6-6.9) and with incident CVEs (OR, 2.7; 95% CI, 1.0-7.1), regardless of age and follow-up. CONCLUSION SH is associated with the risk of incident CVEs. Besides the clinical follow-up, in patients with an AI >2.4 cm, a long-term biochemical follow-up is also required because of the risk of SH development.

Risk of new vertebral fractures in patients with adrenal incidentaloma with and without subclinical hypercortisolism: a multicenter longitudinal study

In patients with adrenal incidentalomas (AIs), cross‐sectional studies suggested the presence of an association between subclinical hypercortisolism (SH) and an increased prevalence of vertebral fractures (VFx) and spinal deformity index (SDI), which is a clinical index of bone quality. No longitudinal studies investigated the incidence of VFx and SDI changes over time in SH. The aim of this study was to evaluate VFx risk and SDI changes in SH over time. One‐hundred‐three consecutive AI patients were studied at baseline and after 12 and 24 months. Patients were divided into SH+ (n = 27) and SH– (n = 76) groups on the basis of the presence of two or more among urinary free cortisol greater than 70 µg/24 hours, serum cortisol after 1‐mg dexamethasone suppression test greater than 3.0 µg/dL, and adrenocorticotropic hormone (ACTH) less than 10 pg/mL in 2 or more of the 3 evaluations. At baseline and after 24 months, bone mineral density (BMD) by dual‐energy X‐ray absorptiometry and the presence of VFx and SDI by summing the grade of deformity for each vertebra were evaluated. At the end of follow‐up, the SH+ group showed a higher prevalence of VFx (81.5%) as compared with baseline (55.6%, p = .04) and a worsening of SDI (2.11 ± 1.85 versus 1.11 ± 1.47, p = .032) associated with SH regardless of age, gender, body mass index , BMD, baseline SDI, menopause duration [odds ratio (OR) = 12.3, 95% confidence interval (CI) 4.1–36.5, p = .001]. The incidence of new vertebral fractures was higher in the SH+ group (48%) than in the SH– group (13%; p = .001). It is concluded that subclinical hypercortisolism is associated with an increased risk of VFx and a possible deterioration of bone quality.

Low levels of 25(OH)D and insulin-resistance: 2 unrelated features or a cause-effect in PCOS?

BACKGROUND & AIMS Recent investigations have identified low vitamin D status as a hypothetical mechanism of insulin-resistance in Polycystic Ovary Syndrome (PCOS). Instead, some authors supported the hypothesis that low vitamin D levels and insulin-resistance are 2 unrelated features of body size in PCOS. Hence, we aimed to explore the association of 25-hydroxyvitamin D (25(OH)D) with anthropometric, metabolic and hormonal features in PCOS. METHODS We assessed the association of low 25(OH)D levels with endocrine parameters, insulin-sensitivity evaluated by hyperinsulinemic euglycemic clamp (HEC) and body composition measured by DEXA in 38 women affected by PCOS. RESULTS Low 25(OH)D (25(OH)D < 50 nmo/L) was detected in 37% of the entire cohort of patients. Body Mass Index (BMI), in particular total fat mass (p < 0.001), resulted to be the most predictor factor of 25(OH)D levels whereas Sex Hormone Binding Globulin (SHBG), Free Androgen Index (FAI), glucose uptake and fat free mass were not. CONCLUSIONS Our data demonstrated that in PCOS low 25(OH)D levels are significantly determined by the degree of adiposity.

High‐normal tsh values in obesity: Is it insulin resistance or adipose tissue's guilt?

Clinical evidences reported subclinical alterations of thyroid function in obesity, although the relationship between thyroid status and obesity remains unclear. We cross‐sectionally investigated the influence of metabolic features on hypothalamic–pituitary–thyroid axis in obesity.

The size of adrenal incidentalomas correlates with insulin resistance. Is there a cause-effect relationship?

Context  Adrenal incidentalomas (AI) have often been associated with a high prevalence of insulin resistance (IR) and cardiovascular risk factors, although direct measurement of insulin sensitivity (IS) has never been carried out.

Does vitamin D play a role in autoimmune endocrine disorders? A proof of concept

In the last few years, more attention has been given to the “non-calcemic” effect of vitamin D. Several observational studies and meta-analyses demonstrated an association between circulating levels of vitamin D and outcome of many common diseases, including endocrine diseases, chronic diseases, cancer progression, and autoimmune diseases. In particular, cells of the immune system (B cells, T cells, and antigen presenting cells), due to the expression of 1α-hydroxylase (CYP27B1), are able to synthesize the active metabolite of vitamin D, which shows immunomodulatory properties. Moreover, the expression of the vitamin D receptor (VDR) in these cells suggests a local action of vitamin D in the immune response. These findings are supported by the correlation between the polymorphisms of the VDR or the CYP27B1 gene and the pathogenesis of several autoimmune diseases. Currently, the optimal plasma 25-hydroxyvitamin D concentration that is necessary to prevent or treat autoimmune diseases is still under debate. However, experimental studies in humans have suggested beneficial effects of vitamin D supplementation in reducing the severity of disease activity. In this review, we summarize the evidence regarding the role of vitamin D in the pathogenesis of autoimmune endocrine diseases, including type 1 diabetes mellitus, Addison’s disease, Hashimoto’s thyroiditis, Graves’ disease and autoimmune polyendocrine syndromes. Furthermore, we discuss the supplementation with vitamin D to prevent or treat autoimmune diseases.

Vitamin D and pancreas: the role of sunshine vitamin in the pathogenesis of Diabetes Mellitus and Pancreatic Cancer

ABSTRACT Increasing evidence suggests that vitamin D exerts multiple effects beyond bone and calcium metabolism. Vitamin D seems to play a role in pancreatic disease, including type 1 and type 2 diabetes mellitus as well as pancreatic cancer. Vitamin Ds immune-modulatory action suggests that it could help prevent type 1 diabetes. In type 2 diabetes, vitamin D may influence β-cell function, insulin sensitivity, and systematic inflammation—all characteristic pathways of that disease. Data from observational studies correlated vitamin D deficiency with risk of type 1 and type 2 diabetes. Prospective and ecological studies of pancreatic cancer incidence generally support a beneficial effect of higher 25-hydroxyvitamin D concentration as well as inverse correlations between UVB dose or exposure and incidence and/or mortality rate of pancreatic cancer. This review discusses the literature regarding vitamin Ds role in risk of diabetes and pancreatic cancer. The results to date generally satisfy Hills criteria for causality regarding vitamin D and incidence of these pancreatic diseases. However, large randomized, blinded, prospective studies are required to more fully evaluate the potential therapeutic role of vitamin D in preventing pancreatic diseases.

Assessment of insulin resistance in lean women with polycystic ovary syndrome.

OBJECTIVE To develop and validate a specific simple measure of insulin sensitivity using oral glucose tolerance test (OGTT) values for lean polycystic ovary syndrome (PCOS) women. DESIGN Retrospective study. SETTING Gynecologic Outpatient Clinic of University Hospital, affiliated with Unit of Gynecologic Endocrinology. PATIENT(S) Totals of 201 lean and 198 overweight/obese (ov-ob) nondiabetic PCOS patients were retrospectively selected. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) All patients underwent OGTT, euglycemic-hyperinsulinemic clamp, and androgenic and biochemical assays. The predictive performance of each insulin resistance (IR) index was analyzed with the use of receiver operating characteristic (ROC) curves. RESULT(S) Higher correlation coefficients with clamp studies were obtained with the Belfiore Area (RS=0.579) and the homeostasis-model assessment (HOMA)-M120 (RS=-0.576) in lean PCOS patients and with the Sib (RS=0.697) in ov-ob PCOS patients. The best predictive index of IR in lean PCOS was a HOMA-M120 value of ≥12.8 or more (area under the ROC curve [AUC] 92.4%). In the ov-ob PCOS population, the best predictive performance was obtained by a Sib of ≤10.2 or less (AUC 85.7%). CONCLUSION(S) IR should be assessed in all PCOS women, both lean and ov-ob subjects. The HOMA-M120 resulted as a very simple tool, validated specifically for the lean PCOS woman whose cardiometabolic impairment is more frequently misunderstood.

Prediction of Vertebral Fractures in Patients With Monolateral Adrenal Incidentalomas

CONTEXT Subtle hypercortisolism is associated with an increased risk of vertebral fracture (VFx). OBJECTIVE The objective was to determine the best parameters of cortisol secretion for detecting the VFx risk in patients with adrenal incidentalomas (AI). DESIGN This was a retrospective (cross-sectional arm) and prospective (longitudinal arm) design. In the cross-sectional arm, we assessed the accuracy of the cortisol secretion indexes in identifying the patients with VFx (prevalent VFx). In the longitudinal arm, we tested the cortisol secretion parameters, which were able to identify the prevalent VFx, for the prediction of the occurrence of a new VFx (incident VFx) in AI patients followed-up for at least 2 years. SETTING Four referral Italian endocrinology units participated in this study. PATIENTS A total of 444 and 126 AI patients without symptoms of hypercortisolism enrolled in the cross-sectional arm and longitudinal arm, respectively. MAIN OUTCOME MEASURES Serum cortisol after a 1-mg dexamethasone suppression test (1 mg DST), urinary free cortisol, ACTH, bone mineral density at lumbar spine and femoral neck (by dual-energy x-ray absorptiometry), and the VFx presence (by x-ray). RESULTS The cortisol levels after 1 mg DST that were greater than 2.0 μg/dl (55 nmol/liter) were the best criteria for detecting patients with both prevalent (73.6% sensitivity, 70.5% specificity) and incident VFx (80% sensitivity, 68.8% specificity) and were associated with a 10-fold increased risk of a new VFx (odds ratio,10.27; 95% confidence interval, 3.39-31.12; P < .0001), regardless of age, gender, bone mineral density at lumbar spine, and prevalent VFx. CONCLUSIONS In AI patients without symptoms of overt hypercortisolism, the cortisol levels after 1 mg DST greater than 2.0 μg/dl (55 nmol/liter) represent the best criterion for detecting prevalent and incident VFx.