Association Between 25(OH)Vitamin D, HbA1c and Albuminuria in Diabetes Mellitus: Data From a Population-Based Study (VIDAMAZON).

Background: The effect of glycemic control on diabetic kidney disease (DKD) is well known. Recent evidence has suggested that Vitamin D (VD) may have a nephroprotective effect in diabetes, but the relationship between VD, glycemic control, and albuminuria has yet to be clarified. Objective: Evaluate the relationship between 25-hydroxy-vitamin D [25(OH)D], HbA1c, and albuminuria in Diabetes Mellitus (DM). Patients and Methods: Cross-sectional study with 1576 individuals with DM who had 25(OH)D, HbA1c, and albuminuria levels measured. Patients with abnormal creatinine levels were excluded, in order to avoid interference on VD levels by impaired kidney function. Results: Patients with HbA1c ≥7% had lower 25(OH)D when compared to patients with HbA1c <7% (29.7 ± 10.2 vs 28.1 ± 9.9 ng/ml, p = 0.003) and 25(OH)D levels seems to predict 1.5% of HbA1c behavior. The 25(OH)D concentrations in patients with normoalbuminuria were higher than the levels observed in those with micro or macroalbuminuria (29.8 ± 9.0 vs 26.8 ± 8.6 and 25.1 ± 7.6, respectively, p = 0.001), patients who had 25(OH)D <20 ng/ml and 25(OH)D <30 ng/ml were at a higher risk of presenting albuminuria [OR = 2.8 (95% CI = 1.6 - 4.9), p<0.001, and OR = 2.1 (95% CI = 1.3 - 4.6), p<0.001, respectively]. In our regression model, albuminuria was influenced by HbA1c (r² = 0.076, p<0.00001) and 25(OH)D (r² = 0.018, p = 0.002) independently. Conclusion: Our study found an association between vitamin D levels, HbA1c and DKD. Additionally, our data suggest that the association between urinary albumin excretion and vitamin D levels is independent of glycemic control in patients with diabetes. Even though our patients presented normal creatinine levels, it is necessary further prospective studies to confirm if this association precedes or not the loss of renal function.

High-dose Cholecalciferol Supplementation Reducing Morning Blood Pressure in Normotensive DM1 Patients.

BACKGROUND: Vitamin D (VD) deficiency has been related to several endocrine metabolic and cardiovascular diseases. The effect of VD supplementation on blood pressure (BP) in patients with diabetes is controversial. OBJECTIVE: The aim of this study was to evaluate high-dose vitamin D supplementation effects on blood pressure of normotensive patients with diabetes mellitus 1 (DM1) patients by 24-hour ambulatory blood pressure monitoring (ABPM). METHODS: We performed a clinical trial including 35 DM1 normotensive patients, who received doses of 4,000 or 10,000 IU/day of cholecalciferol for 12 weeks according to previous VD levels. They underwent 24-hour ABPM, along with glycated hemoglobin, creatine, lipids profile and PCRus dosage before and after VD supplementation. RESULTS: We found an expressive reduction of systolic and diastolic morning blood pressures (117±14 vs 112±14, p<0,05; 74±9 vs 70±10 mmHg, p<0,05, respectively) with no changes in other pressoric markers. Besides, we noticed a relationship between levels of VD after supplementation and diastolic morning blood pressure (r= -0,4; p<0.05). CONCLUSION: Our study suggests an association between supplementation of high doses of vitamin D and the reduction of morning blood pressure in normotensive DM1 patients.

Vitamin D and PTH: data from a cross-sectional study in an equatorial population.

OBJECTIVE: Investigate the prevalence of vitamin D deficiency in an equatorial population through a large-sample study. METHODS: Cross-sectional study with 30,224 healthy individuals from the North Region, in Brazil (Amazônia - state of Pará), who had 25-hydroxy-vitamin D (25(OH)D) and intact parathyroid hormone (PTH) serum levels measured by immunoassay method. Those with history of acute or chronic diseases were excluded. Abnormal levels of calcium, creatinine, glycemia and albumin were also exclusion criteria. RESULTS: 25(OH)D levels were 29.1 ± 8.2 ng/mL and values <12.7 ng/mL were equal to < -2 s.d. below average. Hypovitaminosis D was present in 10% of subjects according to the Institute of Medicine (values <20 ng/mL) and in 59%, in consonance with Endocrine Society (values 20-30 ng/mL as insufficiency and <20 ng/mL as deficiency) criteria. Individuals were divided according to four age brackets: children, adolescents, adults and elderly, and their 25(OH)D levels were: 33 ± 9; 28.5 ± 7.4; 28.3 ± 7.7; 29.3 ± 8.5 ng/mL, respectively. All groups differed in 25(OH)D, except adolescents vs adults. Regression model showed BMI, sex, living zone (urban or rural) and age as independent variables to 25(OH)D levels. Comparing subjects with vitamin D deficiency (<20 ng/mL) to those with vitamin D insufficiency (20-30 ng/mL), a difference between PTH levels in these two groups was observed (95.9 ± 24.7 pg/mL vs 44.2 ± 64.5 pg/mL; P < 0.01). Additionally, the most accurate predictive vitamin D level for subclinical hyperparathyroidism in ROC curve was 26 ng/mL. CONCLUSION: Our equatorial population showed low prevalence of vitamin D hypovitaminosis ranging with age bracket. The insufficient category by Endocrine Society was corroborated by our PTH data.

Diagnosis of Idiopathic GHD in Children Based on Response to rhGH Treatment: The Importance of GH Provocative Tests and IGF-1.

Purpose: Serum IGF-1 (Insulin like growth factor 1) and Growth Hormone (GH) provocative tests are reasonable tools for screening and diagnosis of idiopathic GH Deficiency (IGHD). However, the average cut-off points applied on these tests have a lower level of evidence and produce large amounts of false results. The aim of this study is to evaluate the sensitivity, specificity, and accuracy of IGF-1 and GH stimulation tests as diagnostic tools for IGHD, using clinical response to recombinant human GH (rhGH) treatment as diagnostic standard [increase of at least 0.3 in height standard deviation (H-SD) in 1 year]. Methods: We performed a prospective study with 115 children and adolescents presenting short stature (SS), without secondary SS etiologies such as organic lesions, genetic syndromes, thyroid disorders. They were separated into Group 1 [patients with familial SS or constitutional delay of growth and puberty (CDGP), not treated with rhGH], Group 2 (patients with suspicion of IGHD with clinical response to rhGH treatment), and Group 3 (patients with suspicion of IGHD without growth response to rhGH treatment). Then, they were assessed for diagnostic performance of IGF-1, Insulin Tolerance Test (ITT) and clonidine test (CT) alone and combined at different cut-off points. Results: Based on the ROC curve, the best cut-off points found for IGF-1, ITT, and CT when they were used isolated were -0.492 SDS (sensitivity: 50%; specificity: 53.8%; accuracy: 46.5%), 4.515 µg/L (sensitivity: 75.5%; specificity: 45.5%; accuracy: 52.7%), and 4.095 µg/L (sensitivity: 54.5%; specificity: 52.6%; accuracy: 56.9%), respectively. When we had combined IGF-1 with-2SD as cut-off alongside ITT or CT, we found 7 µg/L as the best cut-off point. In this situation, ITT had sensitivity, specificity and accuracy of 93.9, 81.8, and 90.1%, while CT had 93.2, 68.4, and 85.7%, respectively. Conclusion: Our data suggest that diagnosis of IGHD should be established based on a combination of clinical expertise, auxologic, radiologic, and laboratorial data, using IGF-1 at the -2SD threshold combined, with ITT or CT at the cut-off point of 7 µg/L. Additional studies, similar to ours, are imperative to establish cut-off points based on therapeutic response to rhGH in IGHD, which would be directly related to a better treatment outcome.

Ankle-brachial index and peripheral arterial disease: An evaluation including a type 2 diabetes mellitus drug-naïve patients cohort.

BACKGROUND: Peripheral arterial disease in patients with type 2 diabetes mellitus is an important risk factor for vascular events. Recommendations about whether ankle-brachial index should be performed differ depending on the source; therefore, it is necessary to re-evaluate the most important risk factors associated with peripheral arterial disease and whether it is useful to perform ankle-brachial index in newly diagnosed and drug-naïve patients with diabetes, independent of age or peripheral arterial disease symptoms. METHODS: A total of 711 subjects were divided into groups: group 1, 600 type 2 diabetes mellitus patients, symptomatic or not for peripheral arterial disease; group 2, 61 type 2 diabetes mellitus patients newly diagnosed and drug naïve; and group 3, 50 subjects without diabetes. Ankle-brachial index, medical records and physical examination were performed in all patients, accessing cardiovascular risk factors. RESULTS: Analysing group 1 asymptomatic patient to peripheral arterial disease, we found abnormal ankle-brachial index in 49% (77/156) ⩾50 years and 42% (16/38) <50 years (p = not significant). Considering drug-naïve patients, a peripheral arterial disease prevalence of 39% (24/61) was found; among these, 48% (13/27) were <50 years and 32% (11/34) were ⩾50 years (p = not significant). A forward stepwise regression model was developed, with type 2 diabetes mellitus duration (r2 = 0.12) and sedentary lifestyle (r2 = 0.14) found as independent variable predictors of severity of peripheral arterial disease, related to ankle-brachial index. CONCLUSION: We suggest that, in type 2 diabetes mellitus, ankle-brachial index should be measured at diagnosis. In addition, sedentary lifestyle was strongly associated with presence and severity of peripheral arterial disease.

Cochlear dysfunction and microvascular complications in patients with type 1 diabetes mellitus.

Sensorineural hearing impairment has been associated with DM, and it is probably linked to the same pathophysiological mechanisms as well-established in microvascular diabetes complications. The study of otoacoustic emissions (OAEs) is useful to identify subclinical cochlear dysfunction. Therefore, the aim of this study was to evaluate the association between abnormal OAEs responses, diabetic kidney disease (DKD) and diabetic cardiac autonomic neuropathy (CAN). We performed a cross-sectional study with 37 type 1 DM patients without auditory symptoms, submitted to the study of Distortion Product Otoacoustic Emissions (DPOAEs) and screened for DKD and CAN. The otoacoustic emissions responses were considered abnormal in 27/37 (73%) patients. A correlation was found between abnormal OAEs responses and presence of DKD (r = 0.36, p < 0.05), and 14/16 (88%) patients with a lower amplitude of OAEs in 8 kHz frequency band presented DKD. Abnormal OAEs responses in the 6 kHz frequency band were correlated with the presence (r = 0.41, p = 0.01) and severity of CAN (r = 0.44, p < 0.001). Additionally, 7/9 (78%) patients with abnormal OAE responses in this frequency also presented abnormal CAN scores. Our results suggest that abnormal otoacoustic emissions responses in high frequency bands are associated with diabetes microvascular complications and could be a risk marker for DKD and CAN, presenting low sensitivity and high specificity. Therefore, assuming that hearing impairment is a pre-clinical stage of hearing loss, performing distortion product otoacoustic emissions in T1DM patients with microvascular complications could be useful to identify those who would be benefit with regular audiologic follow up and tighter diabetes control.

Glycemic Variability and Insulin Needs in Patients with Type 1 Diabetes Mellitus Supplemented with Vitamin D: A Pilot Study Using Continuous Glucose Monitoring System.

BACKGROUND: Recent studies suggest that glycemic variability could influence the risk of complications in Type 1 Diabetes Mellitus (T1DM). There are no data about the action of Vitamin D (VD) on glycemic variability. Our pilot study aims to evaluate glycemic variability and insulin needs in patients with T1DM supplemented with VD. METHODS: 22 Patients received doses of 4000 and 10000 IU/day of cholecalciferol for 12 weeks, according to the patient's baseline VD levels and underwent continuous glucose monitoring system. RESULTS: Correlations were found between percentage variation (Δ) of glycemia standard deviation (ΔSDG), calculated using continuous glucose monitoring, with Δ of basal (r = 0.6; p <0.01) and total insulin dose (r = 0.6; p <0.01). Correlations between VD status after supplementation and Δ of prandial (r = 0.5; p <0.05) and total insulin dose (r = 0.4; p <0.05) were found, suggesting that the dose of insulin needed by patients is lower when VD status is better. We divided patients in two subgroups: SDG improved (subgroup 1; N = 12 (55%)) and SDG worsened (subgroup 2; N = 10 (45%)). Group 1, compared to subgroup 2, required a lower insulin dose (Δbasal insulin dose = -8.0 vs. 6.3%; p <0.05) and had a lower frequency of hypoglycemia (27% vs. 64%, hypoglycemias/days evaluated; p <0.01). CONCLUSION: Our study suggests a relation between VD supplementation, improved glycemic variability, lower insulin needs and lower frequency of hypoglycemia in patients with T1DM.

Vitamin D on Early Stages of Diabetic Kidney Disease: A Cross-sectional Study in Patients with Type 1 Diabetes Mellitus.

CONTEXT: Genetic and environmental factors are involved in the pathogenesis of type 1 diabetes mellitus (T1DM), and vitamin D (VD) deficiency appears as a candidate to risk factor for developing diabetic kidney disease (DKD). OBJECTIVE: The purpose of study was to evaluate the existence of an association between low levels of VD and the presence and degree of DKD in T1DM. PATIENTS AND METHODS: We performed a cross-sectional study, between November 2014 and December 2015. Levels of 25(OH)D and albuminuria were analyzed in 37 patients with T1DM and normal glomerular filtration rate. Thirty-six subjects were evaluated as a control group. RESULTS: Patients with T1DM and hypovitaminosis D had higher levels of albuminuria compared to those with normal VD levels [albuminuria (log10) = 1.92 vs. 1.44; p < 0.05]. When we have separated the group of patients according to stage of DKD in patients with normo, micro, and macroalbuminuria, there are lower levels of 25(OH)D in the last when compared to the first two groups (26.7 ± 6.2, 24.8 ± 7.0, and 15.9 ± 7.6 ng/ml; p < 0.05, respectively). In T1DM group, we have found correlations between VD levels and both albuminuria and DKD stages (r = -0.5; p < 0.01 and r = -0.4; p < 0.05, respectively). A simple linear regression model, with albuminuria as the dependent variable and VD as an independent variable, showed r2 = 0.2 and p < 0.01. CONCLUSION: Our data suggest an association between reduced levels of VD and the presence and severity of DKD.