Vitamin D at the onset of type 1 diabetes in Italian children

Proportion of vitamin D deficiency in children/adolescents with type 1 diabetes: a systematic review and meta-analysis

BACKGROUND

The impact of vitamin D on type 1 diabetes has been a controversial topic in public health. Furthermore, significant differences in the proportion of vitamin D have been noted. The purpose of this systematic review was to determine the overall proportion of vitamin D deficiency in children/adolescents with type 1 diabetes (T1D).

METHODS

Based on six electronic databases (PubMed, Web of Science, Embase, Ovid Medline, ProQuest, and Cochrane Library), eligible studies since the databases' inception up to April 2022 were searched. Reference lists were also manually searched to identify additional studies. Overall, studies with statistical information on vitamin D deficiency in children and adolescents with T1D were included, and a random effects model was applied for the meta-analysis. In addition, subgroup and sensitivity analyses were carried out to evaluate heterogeneity, and publication bias was evaluated by using Egger's test.

RESULTS

A total of 45 studies involving 6,995 participants met the inclusion criteria; these included 25 countries covering Africa, Oceania, Europe, North America and Asia. The proportion of vitamin D deficiency in children/adolescents with T1D was 45% (95% confidence interval [CI] 37-54%, I2 = 97.94%). Subgroup analysis further revealed that the publication year, study design, vitamin D classification, season and geographical region significantly contributed to the variation in the reported incidence of vitamin D deficiency.

CONCLUSIONS

The results of the meta-analysis showed that the proportion of vitamin D deficiency among T1D children/adolescents was 45%. In addition, the proportion remains higher, which has important implications for adapting health and social care systems.

Predicting the development of T1D and identifying its Key Performance Indicators in children; a case-control study in Saudi Arabia

The increasing incidence of type 1 diabetes (T1D) in children is a growing global concern. It is known that genetic and environmental factors contribute to childhood T1D. An optimal model to predict the development of T1D in children using Key Performance Indicators (KPIs) would aid medical practitioners in developing intervention plans. This paper for the first time has built a model to predict the risk of developing T1D and identify its significant KPIs in children aged (0-14) in Saudi Arabia. Machine learning methods, namely Logistic Regression, Random Forest, Support Vector Machine, Naive Bayes, and Artificial Neural Network have been utilised and compared for their relative performance. Analyses were performed in a population-based case-control study from three Saudi Arabian regions. The dataset (n = 1,142) contained demographic and socioeconomic status, genetic and disease history, nutrition history, obstetric history, and maternal characteristics. The comparison between case and control groups showed that most children (cases = 68% and controls = 88%) are from urban areas, 69% (cases) and 66% (control) were delivered after a full-term pregnancy and 31% of cases group were delivered by caesarean, which was higher than the controls (χ2 = 4.12, P-value = 0.042). Models were built using all available environmental and family history factors. The efficacy of models was evaluated using Area Under the Curve, Sensitivity, F Score and Precision. Full logistic regression outperformed other models with Accuracy = 0.77, Sensitivity, F Score and Precision of 0.70, and AUC = 0.83. The most significant KPIs were early exposure to cow's milk (OR = 2.92, P = 0.000), birth weight >4 Kg (OR = 3.11, P = 0.007), residency(rural) (OR = 3.74, P = 0.000), family history (first and second degree), and maternal age >25 years. The results presented here can assist healthcare providers in collecting and monitoring influential KPIs and developing intervention strategies to reduce the childhood T1D incidence rate in Saudi Arabia.

Factors Associated With Diabetic Ketoacidosis at Onset of Type 1 Diabetes Among Pediatric Patients: A Systematic Review

IMPORTANCE

Presenting with diabetic ketoacidosis (DKA) at onset of type 1 diabetes (T1D) remains a risk. Following a 2011 systematic review, considerable additional articles have been published, and the review required updating.

OBJECTIVE

To evaluate factors associated with DKA at the onset of T1D among pediatric patients.

EVIDENCE REVIEW

In this systematic review, PubMed, Embase, Scopus, CINAHL, Web of Science, and article reference lists were searched using the population, intervention, comparison, outcome search strategy for primary research studies on DKA and T1D onset among individuals younger than 18 years that were published from January 2011 to November 2021. These studies were combined with a 2011 systematic review on the same topic. Data were pooled using a random-effects model.

FINDINGS

A total of 2565 articles were identified; 149 were included, along with 46 from the previous review (total 195 articles). Thirty-eight factors were identified and examined for their association with DKA at T1D onset. Factors associated with increased risk of DKA were younger age at T1D onset (<2 years vs ≥2 years; odds ratio [OR], 3.51; 95% CI, 2.85-4.32; P < .001), belonging to an ethnic minority population (OR, 0.40; 95% CI, 0.21-0.74; P = .004), and family history of T1D (OR, 0.46; 95% CI, 0.37-0.57; P < .001), consistent with the 2011 systematic review. Some factors that were not associated with DKA in the 2011 systematic review were associated with DKA in the present review (eg, delayed diagnosis: OR, 2.27; 95% CI, 1.72-3.01; P < .001). Additional factors associated with risk of DKA among patients with new-onset T1D included participation in screening programs (OR, 0.35; 95% CI, 0.21-0.59; P < .001) and presentation during the COVID-19 pandemic (OR, 2.32; 95% CI, 1.76-3.06; P < .001).

CONCLUSIONS AND RELEVANCE

In this study, age younger than 2 years at T1D onset, belonging to an ethnic minority population, delayed diagnosis or misdiagnosis, and presenting during the COVID-19 pandemic were associated with increased risk of DKA. Factors associated with decreased risk of DKA included greater knowledge of key signs or symptoms of DKA, such as a family history of T1D or participation in screening programs. Future work should focus on identifying and implementing strategies related to these factors to reduce risk of DKA among new patients with T1D.

Vitamin D and Healthcare Service Utilization in Children: Insights from a Machine Learning Approach

Vitamin D deficiency and insufficiency is a global health issue: an association has been demonstrated between vitamin D deficiency and a myriad of acute and chronic illnesses. Data regarding vitamin D status among children hospitalized with non-critical illnesses are scanty. We aimed to: (1) identify profiles of children hospitalized due to non-critical illnesses, using vitamin D levels as the driving outcome; (2) assess the association between patient profiles and length of stay. The study included 854 patients (1−17 years old) who underwent blood tests for detecting vitamin D levels. A regression tree was used to stratify patients. The relationship between vitamin D levels and length of stay was explored using Poisson regression. The regression tree identified three subgroups. Group A (16%): African, North African, Hispanic, and Indian patients. Group B (62%): Caucasian and Asian patients hospitalized for respiratory, metabolic, ill-defined, infective, and genitourinary diseases. Group C (22%): Caucasian and Asian patients hospitalized for digestive, nervous, and musculoskeletal diseases, blood and skin diseases, and injuries. Mean serum vitamin D level (ng/mL) was 13.7 (SD = 9.4) in Group A, 20.5 (10.0) in Group B, and 26.2 (12.6) in Group C. Group B was associated with the highest BMI z-score (p < 0.001) and the highest frequency of preterm births (p = 0.041). Mean length of stay was longer in Group A than in the other groups (p < 0.001) and decreased significantly by 9.8% (p = 0.024) in Group A and by 5% (p = 0.029) in Group B per 10 ng/mL increase in vitamin D level. We identified three subgroups of hospitalized children, defined according to ethnicity and discharge diagnosis, and characterized by increasing vitamin D levels. Vitamin D levels were associated with length of hospitalization.

Vitamin D Deficiency as a Possible Cause of Type 1 Diabetes in Children and Adolescents up to 15 Years Old: A Systematic Review

OBJECTIVE: To evaluate vitamin D ((25OH)D levels) deficiency as a possible cause in the development of DT1 in children and adolescents aged 0-15. METHODS: We searched PubMed/ Medline, EBSCO, and Cochrane Library to identify potentially eligible articles that examine whether low serum 25(OH)D levels are associated with subsequent development of DT1. All type of research designs, including randomized and non-randomized controlled trials, prospective and retrospective cohort studies, case- control and cross-sectional studies with subjects aged ≤15 years old were consider for inclusion. RESULTS: Seven original studies met the entry criteria. Most of these studies found up to 50% lower levels of vitamin D in children with DT1 compared to control group and a significant positive association between vitamin D levels and of the risk of developing DT1. Results of quality assessment demonstrated moderate to high quality of all the studies included. CONCLUSIONS: Vitamin D deficiency may be a possible cause in the development of DT1 in the early years of life and particularly in children with genetic predisposition, whilst the deficiency of vitamin D is a very common occurrence in patients with DT1. Further long-term studies on children are required to determine the role of vitamin D on DT1.

Vitamin D Supplementation Modulates ICOS+ and ICOS- Regulatory T Cell in Siblings of Children With Type 1 Diabetes

OBJECTIVES

Vitamin D plays an immunoregulatory activity. The aim of this study was to assess the correlation between blood serum 25(OH)D levels and Th17 and Treg circulating subsets, mainly Treg/inducible costimulatory-positive (ICOS+), which seems to have a protective role in autoimmunity, in children with type 1 diabetes mellitus (T1D) and their healthy siblings (S). The secondary aim was to evaluate the impact of vitamin D supplementation on these subsets.

PATIENTS AND METHODS

22 T1D and 33 S were enrolled. Glucose, hemoglobin A1c, 25 OH vitamin D (25[OH]D), T helper type 17 (Th17; CD4+CCR6+), regulatory T cells (Treg; CD4+CD25+Foxp3+), and Treg/ICOS+ cells were evaluated. According to human leukocyte antigen (HLA) haplotypes, subjects were classified as "at risk" (HLA+), "protective haplotypes" (HLA-; "nested controls"), and "undetermined" (HLAUND). T1D and S subjects were supplemented with cholecalciferol 1000 IU/die and evaluated after 6 months.

RESULTS

Vitamin D insufficiency (74.4%) and deficiency (43%) were frequent. S subjects with 25(OH)D levels <25 nmol/L had Th17, Treg (p < 0.01), and Treg/ICOS+ (P < 0.05) percentages higher than subjects with 25(OH)D >75 nmol/L. Treg/ICOS+ percentages (P < 0.05) were higher in HLA- S subjects compared to percentages observed in S with T1D. At baseline, in S subjects, a decreasing trend in Th17 and Treg/ICOS+ values (P < 0.05) from vitamin D deficiency to sufficiency was observed; 25(OH)D levels were negative predictors of Treg/ICOS+ (R2 = 0.301) and Th17 percentages (R2 = 0.138). After 6 months, supplemented S subjects showed higher 25(OH)D levels (P < 0.0001), and lower Th17 (P < 0.0001) and Treg/ICOS+ (P < 0.05) percentages than at baseline; supplemented T1D patients only had a decrease in Th17 levels (P < 0.05).

CONCLUSION

Serum 25(OH)D levels seem to affect Th17 and Treg cell subsets in S subjects, consistent with its immunomodulating role. HLA role should be investigated in a larger population.

A dose-response meta-analysis between serum concentration of 25-hydroxy vitamin D and risk of type 1 diabetes mellitus

It remains debatable whether vitamin D plays any role as a risk factor for type 1 diabetes mellitus (T1DM). We have summarized the effect of circulating 25-hydroxy vitamin D [25(OH)D] concentration on the risk of developing T1DM via a dose-response meta-analysis. We undertook a database search on PubMed, Embase, and Cochrane Library from inception to January 2020. A meta-analysis based on random-effects model was applied. Subgroup analysis and meta-regression were performed to inspect the source of heterogeneity. Dose-response data were examined using the generalized least squares trend estimation method. This study was registered with the PROSPERO (ID: CRD42020166174). In total, 16 studies including 10,605 participants (3913 case patients) were included. The pooled odds ratios (OR) and 95% confidence intervals (95% CI) for the highest versus the lowest 25(OH)D concentration was 0.39 (0.27, 0.57), with a high heterogeneity (I² = 76.7%, P < 0.001). Meta-regression analysis identified latitude (P = 0.02), adjustment for gender (P = 0.001), and 25(OH)D stratification (P < 0.001) as sources of heterogeneity. Furthermore, the nonlinear dose-response analysis determined the OR (95% CI) of T1DM to be 0.91 (0.90, 0.93) per 10 nmol/L increase in the 25(OH)D concentration. A 'U'-shaped association was found between serum 25(OH)D concentration and risk of T1DM. The present study highlights the significant inverse association between the circulating 25(OH)D concentration and the risk of T1DM.

Vitamin D status is related to severity at onset of diabetes and worse glycemic control

Objectives Our aim is to evaluate whether 25-hydroxyvitamin D at onset of type 1 diabetes mellitus (T1DM) would influence analytical variables of worse prognosis of the disease at the beginning and after one year of development. Methods A retrospective study of pediatric patients (0-14 years) diagnosed with T1DM with initial measurements of 25-hydroxyvitamin D was performed at Son Espases Hospital, between March 2012 and April 2019 (n=67). Results Vitamin D insufficiency was related to age, glycosylated hemoglobin, and creatinine. An improvement in glycosylated hemoglobin was found in subjects whose baseline serum 25(OH)D was >30 ng/mL. Bivariate correlation analysis adjusted by age showed a significantly positive correlation of vitamin D with pH (r=0.279), bicarbonate (r=0.338), and free levothyroxine (r=0.293). Independent variables associated with vitamin D insufficiency were age (odds ratio [OR]=1.2) and winter season (OR=10.52). Conclusion Hypovitaminosis D is related to biochemical variables showing greater severity and higher glycosylated hemoglobin at diagnosis: higher creatinine, lower free levothyroxine, pH, and bicarbonate. Unsupplemented patients with baseline deficiency showed persistently worse glycemic control vs. those with baseline repletion.

Autoimmune thyroid disease and type 1 diabetes mellitus: same pathogenesis; new perspective?

Autoimmune thyroid disease (AITD) and type 1 diabetes mellitus (T1DM) are two common autoimmune diseases that can occur concomitantly. In general, patients with diabetes have a high risk of AITD. It has been proposed that a complex genetic basis together with multiple nongenetic factors make a variable contribution to the pathogenesis of T1DM and AITD. In this paper, we summarize current knowledge in the field regarding potential pathogenic factors of T1DM and AITD, including human leukocyte antigen, autoimmune regulator, lymphoid protein tyrosine phosphatase, forkhead box protein P3, cytotoxic T lymphocyte-associated antigen, infection, vitamin D deficiency, and chemokine (C-X-C motif) ligand. These findings offer an insight into future immunotherapy for autoimmune diseases.

Vitamin D and ω-3 Supplementations in Mediterranean Diet During the 1st Year of Overt Type 1 Diabetes: A Cohort Study

Vitamin D and omega 3 fatty acid (ω-3) co-supplementation potentially improves type 1 diabetes (T1D) by attenuating autoimmunity and counteracting inflammation. This cohort study, preliminary to a randomized control trial (RCT), is aimed at evaluating, in a series of T1D children assuming Mediterranean diet and an intake of cholecalciferol of 1000U/day from T1D onset, if ω-3 co-supplementation preserves the residual endogen insulin secretion (REIS). Therefore, the cohort of 22 “new onsets” of 2017 received ω-3 (eicosapentenoic acid (EPA) plus docosahexaenoic acid (DHA), 60 mg/kg/day), and were compared retrospectively vs. the 37 “previous onsets” without ω-3 supplementation. Glicosilated hemoglobin (HbA1c%), the daily insulin demand (IU/Kg/day) and IDAA1c, a composite index (calculated as IU/Kg/day × 4 + HbA1c%), as surrogates of REIS, were evaluated at recruitment (T0) and 12 months later (T12). In the ω-3 supplemented group, dietary intakes were evaluated at T0 and T12. As an outcome, a decreased insulin demand (p < 0.01), particularly as pre-meal boluses (p < 0.01), and IDAA1c (p < 0.01), were found in the ω-3 supplemented group, while HbA1c% was not significantly different. Diet analysis in the ω-3 supplemented group, at T12 vs. T0, highlighted that the intake of arachidonic acid (AA) decreased (p < 0.01). At T0, the AA intake was inversely correlated with HbA1c% (p < 0.05; r;. 0.411). In conclusion, the results suggest that vitamin D plus ω-3 co-supplementation as well as AA reduction in the Mediterranean diet display benefits for T1D children at onset and deserve further investigation.

Low levels of 25-hydroxyvitamin D in children and adolescents with type 1 diabetes mellitus: a single center experience

PURPOSE

Low vitamin D level is common in adults with diabetes mellitus (DM). We assessed vitamin D level and its associated factors in Korean youth with type 1 DM.

METHODS

Type 1 DM cases (n=85) and healthy controls (n=518) aged <20 years were included and grouped into 3 categories according to vitamin D level: deficiency (<20 ng/mL), insufficiency (20-30 ng/mL), or sufficiency (≥30 ng/mL).

RESULTS

The mean serum vitamin D level was significantly lower (21.6±8.5 ng/mL vs. 28.0±12.0 ng/mL, P<0.001) and vitamin D deficiency prevalence was significantly higher (48% vs. 26%, P<0.001) in type 1 DM cases than in healthy controls. Logistic regression analysis revealed that type 1 DM cases were more likely to have vitamin D deficiency (P=0.004), independent of sex, age, and body mass index. Type 1 DM cases with vitamin D deficiency/insufficiency were mainly diagnosed in winter (November to April) (P=0.005), and the duration of diabetes was longer than in those with vitamin D sufficiency (P=0.046). However, season of diagnosis, duration of diabetes, prescribed daily insulin dose, and glycosylated hemoglobin and C-peptide levels were not associated with 25-hydroxyvitamin D (25(OH)D) level in type 1 DM cases after adjustment for other factors.

CONCLUSIONS

We recommend assessment of serum 25(OH)D level in type 1 DM cases and to treatment if findings indicate insufficiency. Further studies investigating the mechanisms underlying vitamin D deficiency in youth with type 1 DM are needed.

Lower vitamin D intake is associated with low HDL cholesterol and vitamin D insufficiency/deficiency in Brazilian children

OBJECTIVE

To evaluate the association of vitamin D intake with dyslipidaemia and vitamin D insufficiency/deficiency in Brazilian children and identify the main food group sources of this nutrient in the sample.

DESIGN

A cross-sectional study carried out with a representative sample. Blood was collected after 12 h of fasting. Laboratory tests were performed to determine total cholesterol, HDL cholesterol (HDL-C), LDL cholesterol, TAG, apoB, apoA1, 25-hydroxyvitamin D and parathyroid hormone. Dietary intake was evaluated by a 24 h recall.

SETTING

Viçosa, Minas Gerais, Brazil.

SUBJECTS

Children between 8 and 9 years old enrolled in urban schools (n 378).

RESULTS

We found an elevated prevalence of inadequate vitamin D intake (91·3 %), dyslipidaemia (72·8 %) and vitamin D insufficiency/deficiency (56·2 %). The food groups that contributed the most to vitamin D intake were dairy products and fish. Lower vitamin D intake was associated with increased prevalence of both low HDL-C (prevalence ratio=2·51; 95 % CI 1·02, 6·18; P<0·05) and vitamin D insufficiency/deficiency (prevalence ratio=1·61; 95 % CI 1·01, 2·58; P<0·05).

CONCLUSIONS

Given the elevated prevalence of inadequate vitamin D intake and its association with low HDL-C and vitamin D insufficiency/deficiency, it is important to develop specific actions in food and nutritional education as well as programmes that stimulate and facilitate access to vitamin D food sources, such as dairy products and fish.

Plasma 25-Hydroxyvitamin D Concentration and Risk of Islet Autoimmunity

We examined the association between plasma 25-hydroxyvitamin D [25(OH)D] concentration and islet autoimmunity (IA) and whether vitamin D gene polymorphisms modify the effect of 25(OH)D on IA risk. We followed 8,676 children at increased genetic risk of type 1 diabetes at six sites in the U.S. and Europe. We defined IA as positivity for at least one autoantibody (GADA, IAA, or IA-2A) on two or more visits. We conducted a risk set sampled nested case-control study of 376 IA case subjects and up to 3 control subjects per case subject. 25(OH)D concentration was measured on all samples prior to, and including, the first IA positive visit. Nine polymorphisms in VDR, CYP24A, CYP27B1, GC, and RXRA were analyzed as effect modifiers of 25(OH)D. Adjusting for HLA-DR-DQ and ancestry, higher childhood 25(OH)D was associated with lower IA risk (odds ratio = 0.93 for a 5 nmol/L difference; 95% CI 0.89, 0.97). Moreover, this association was modified by VDR rs7975232 (interaction P = 0.0072), where increased childhood 25(OH)D was associated with a decreasing IA risk based upon number of minor alleles: 0 (1.00; 0.93, 1.07), 1 (0.92; 0.89, 0.96), and 2 (0.86; 0.80, 0.92). Vitamin D and VDR may have a combined role in IA development in children at increased genetic risk for type 1 diabetes.

Seasonality and autoimmune diseases: The contribution of the four seasons to the mosaic of autoimmunity

Autoimmune diseases (ADs) are a heterogeneous groups of diseases that occur as a results of loss of tolerance to self antigens. While the etiopathogeneis remain obscure, different environmental factors were suggested to have a role in the development of autoimmunity, including infections, low vitamin D levels, UV radiation, and melatonin. Interestingly, such factors possess seasonal variation patterns that could influence disease development, severity and progression. Vitamin D levels which reach a nadir during late winter and early spring is correlated with increased disease activity, clinical severity as well as relapse rates in several disease entities including multiple sclerosis (MS), non-cutaneous flares of systemic lupus erythematosus (SLE), psoriasis, and rheumatoid arthritis (RA). Additionally, immunomodulatory actions of melatonin secretion ameliorate the severity of several ADs including MS and SLE. Melatonin levels are lowest during spring, a finding that correlates with the highest exacerbation rates of MS. Further, melatonin is postulated to be involved in the etiopathogenesis of inflammatory bowel diseases (IBD) through it influence on adhesion molecule and therefore transcription factor expression. Moreover, infections can mount to ADs through pro-inflammatory cytokine release and human antigen mimicry. Seasonal patterns of infectious diseases are correlated with the onset and exacerbation of ADs. During the winter, increased incidence of Epstein-Barr virus (EBV) infectious are associated with MS and SLE flares/onset respectively. In addition, higher Rotavirus infections during the winter precedes type 1 diabetes mellitus onset (T1DM). Moreover, Escherichia coli (E. coli) infection prior to primary biliary cirrhosis (PBC) and T1DM disease onset subsequent to Coxachievirus infections are seen to occur during late summer, a finding that correlate with infectious agents' pattern of seasonality. In this review, the effects of seasonality on the onset, relapses and activity of various ADs were discussed. Consideration of seasonal variation patterns of ADs can possibly provide clues to diseases pathogenesis and lead to development of new approaches in treatment and preventative care.

Low vitamin D level in pediatric patients with new onset type 1 diabetes is common, especially if in ketoacidosis

BACKGROUND

Vitamin D deficiency (VDD) adversely affects bone health. US data on prevalence of VDD or vitamin D insufficiency (VDI) at diagnosis of type 1 diabetes (T1D) is lacking. Low serum 25-hydroxyvitamin D (25OHD) is speculated to increase the risk of developing T1D.

OBJECTIVES

Assess the prevalence of pediatric VDD and VDI at diagnosis of T1D, and investigate correlations with demographic and clinical parameters.

METHODS

We performed a retrospective Institutional Review Board (IRB)-approved chart review of all T1D cases diagnosed from January 2011 to August 2012, all having the same 25OHD assay performed at Quest Diagnostics. Definitions for VDD, VDI, and vitamin D sufficiency (VDS) were 25OHD levels (ng/mL) ≤ 20, 21-29, and ≥ 30, respectively. We termed 25OHD <30 ng/mL as Low-D.

RESULTS

We identified 185 autoantibody positive T1D subjects (51% female) with 25OHD measured, 51% Caucasian, 25% Hispanic, 4% mixed-Hispanic, 4% African American, and 16% other/mixed race. Mean age 9.8 yr (0.9-18.6). Most had Low-D (58%), 40% VDI, 18% VDD, and 42% VDS. No gender or age differences among the 25OHD groups. Low-D was more common (p < 0.0001) in Hispanics (81%) vs Caucasians (44%), but VDD rates were similar. Low-D subjects were heavier than VDS (p = 0.018). All four with elevated celiac titers were VDS. Diabetic ketoacidosis was present in 33%, but more common (44%) in Low-D vs. VDS (18%) (p < 0.0001), and trended higher in VDD (61%) vs. VDI (36%). Seventy-seven percentage with DKA had Low-D.

CONCLUSION

VDD and insufficiency are common, even in Caucasians, at onset of T1D in pediatrics, worse in those with DKA.

Vitamin D Deficiency and Glycemic Status in Children and Adolescents with Type 1 Diabetes Mellitus

BACKGROUND

Vitamin D (25OHD) effects on glycemic control are unclear in children and adolescents with type 1 diabetes. Aims of this study were to investigate 25OHD status among children with T1DM and its relationship with insulin sensitivity and glycemic status.

SUBJECTS AND METHODS

A cross sectional study was carried out between 2008-2014. A total of 141 patients had a T1DM >12 months diagnosis and were enrolled in the present study. Of these 35 (24.8%) were migrants and 106 (75.2%) Italians (T2). We retrospectively analyzed data at the onset of the disease (T0)(64 subjects) and 12-24 months before the last visit (T1,124 subjects). Fasting glucose, glycated hemoglobin (HbA1c), 25OHD levels and daily insulin requirement were evaluated and Cholecalciferol 1000 IU/day supplementation for the management of vitamin D insufficiency (<75 nmol/L) was systematically added.

RESULTS

A generalized 25OHD insufficiency was found at each study time, particularly in migrants. At T0, the 25OHD levels were inversely related to diabetic keto-acidosis (DKA) severity (p<0.05). At T1 and T2, subjects with 25OHD ≤25nmol/L (10 ng/mL) showed higher daily insulin requirement (p<0.05) and HbA1c values (p<0.01) than others vitamin D status. The 25OHD levels were negatively related with HbA1c (p<0.001) and daily insulin dose (p<0.05) during follow up. There was a significant difference in 25OHD (p<0.01) between subjects with different metabolic control (HbA1c <7.5%,7.5-8%,>8%), both at T1 and T2. In supplemented subjects, we found a significant increase in 25OHD levels (p<0.0001) and decrease of HbA1c (p<0.001) between T1 and T2, but this was not significant in the migrants subgroup. Multivariate regression analysis showed a link between HbA1c and 25OHD levels (p<0.001).

CONCLUSIONS

Children with T1DM show a generalized 25OHD deficiency that impact on metabolic status and glycemic homeostasis. Vitamin D supplementation improves glycemic control and should be considered as an additional therapy.

Lower serum 25 (OH) D concentrations in type 1 diabetes: A meta-analysis

OBJECTIVE

Vitamin D may have protective effects against type 1 diabetes (T1D). However, the results of current cross-sectional studies have been inconsistent. We aimed to examine the association of serum vitamin D and T1D by conducting a meta-analysis.

METHODS

Multiple databases were searched until April 2014 to identify relevant studies. The search term was "serum vitamin D" and "type 1 diabetes". Random effects model was used to calculate the pooled risk estimate. The data were accessed by software Review manager 5.2.

RESULTS

We included a total of 23 studies (11 studies with 1900 participants of children or adolescents and 13 studies with 3494 participants of adults) in our meta-analysis. In children or adolescents, serum 25(OH) D in T1D was 5.69 ng/ml [95% confidence interval (CI) (2.82-8.55, P<0.0001) lower than in healthy controls. In adults, serum 25(OH) D in T1D was 2.61 ng/ml [95% confidence interval (CI) (1.13-4.09, P=0.0005) lower than in healthy controls. We did not find evidence of publication bias.

CONCLUSION

Serum 25OHD is significantly lower in patients with T1D than in healthy controls.

25-hydroxyvitamin D serum level in children of different ethnicity living in Italy

Several factors including ethnicity are known to influence 25(OH)D levels. The purpose of our study was to assess 25(OH)D levels among 1374 pediatric subjects of different ethnicity and to determine the prevalence of vitamin D deficiency and insufficiency among different ethnic groups. The prevalence of 25(OH)D ≤ 20 ng/ml was 44.2, 65.2, 69.2, 54.0, and 44.8 % among Caucasians, Africans, North Africans, Indians, and others, respectively (P < 0.001). The median of 25(OH)D was 21.0 ng/ml (IQR = 14.0-29.6 ng/ml) for the cohort. Season of blood sampling, age, ethnicity, gestational age, birth weight, and z-score BMI were associated with 25(OH)D levels. Caucasians had higher median 25(OH)D levels than sub-Saharan Africans (P < 0.001), North Africans (P < 0.001), and Indians (P < 0.001). There were no significant differences in the median 25(OH)D levels between ethnic groups among infants, whereas for children older than 1 year we found significant differences in 25(OH)D levels in the different ethnic groups, compared to Caucasians.

CONCLUSION

Ethnicity was correlated with 25(OH)D levels among children older than 1 year. We found a high prevalence of vitamin D deficiency and insufficiency after the first year of life, and this was more remarkable in non-Caucasian children.

Vitamin D in inflammatory diseases

Changes in vitamin D serum levels have been associated with inflammatory diseases, such as inflammatory bowel disease (IBD), rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis (MS), atherosclerosis, or asthma. Genome- and transcriptome-wide studies indicate that vitamin D signaling modulates many inflammatory responses on several levels. This includes (i) the regulation of the expression of genes which generate pro-inflammatory mediators, such as cyclooxygenases or 5-lipoxygenase, (ii) the interference with transcription factors, such as NF-κB, which regulate the expression of inflammatory genes and (iii) the activation of signaling cascades, such as MAP kinases which mediate inflammatory responses. Vitamin D targets various tissues and cell types, a number of which belong to the immune system, such as monocytes/macrophages, dendritic cells (DCs) as well as B- and T cells, leading to individual responses of each cell type. One hallmark of these specific vitamin D effects is the cell-type specific regulation of genes involved in the regulation of inflammatory processes and the interplay between vitamin D signaling and other signaling cascades involved in inflammation. An important task in the near future will be the elucidation of the regulatory mechanisms that are involved in the regulation of inflammatory responses by vitamin D on the molecular level by the use of techniques such as chromatin immunoprecipitation (ChIP), ChIP-seq, and FAIRE-seq.