Vitamin D Abstracts 6

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Effect of one time high dose "stoss therapy" of vitamin D on glucose homeostasis in high risk obese adolescents.
            (Brar et al., 2018) Download
OBJECTIVE:  To study the effect of using a one time high dose "stoss therapy" of vitamin D2 (ergocalciferol: VD2) on indices of insulin sensitivity (Brar et al., 2018) and secretion (Brar et al., 2018) measured during an oral glucose tolerance test (OGTT) in obese adolescents with VDD (25 OHD; serum metabolite of vit D: < 30 ng/dL). SUBJECTS AND METHODS:  In a randomized placebo controlled cross over design 20 obese adolescents with vitamin D deficiency (VDD) had baseline OGTT. Arm A received one time high dose 300,000 IU of ergocalciferol and Arm B received placebo. After 6 weeks the adolescents were reassigned to Arm A if they were in Arm B and vice versa. 25OHD, calcium, parathyroid hormone, comprehensive metabolic panel, urine calcium creatinine ratio were measured at each study visit. OGTTs to assess indices of sensitivity and secretion were done at baseline, 6 weeks and 12 weeks respectively. RESULTS:  Adolescents were obese and insulin resistant (mean ± SD: mean age = 15.1 ± 1.9 years; BMI: 32.7 ± 9.8; homeostatic model of insulin resistance: HOMA-IR: 4.2 ± 2.8). Stoss therapy with VD2 increased 25OHD from baseline (16.7 ± 2.9 to 19.5 ± 4.5; p = 0.0029) when compared to the placebo. WBISI (2.8 ± 1.9) showed a trend towards improvement in Rx group (p = 0.0577) after adjustment for covariates. IGI (3 ± 2.2) showed an improvement in both Rx and placebo groups. CONCLUSIONS:  Our study demonstrated that using a high dose of VD2 (300,000 IU) did not have any beneficial effect on insulin sensitivity (whole body sensitivity index (Brar et al., 2018)) and secretory indices (insulinogenic index (Brar et al., 2018)) in obese adolescents. High dose "stoss therapy" of VD2 did not appear to have any beneficial effect on glucose homeostasis on obese adolescents.

Vitamin D supplementation and diabetes-related autoimmunity in the ABIS study.
            (Brekke and Ludvigsson, 2007) Download
Supplementation with vitamin D during infancy, as well as intake of vitamin D during pregnancy, has been associated with decreased risk of type 1 diabetes or diabetes-related autoantibodies in children. The primary aim of this report was to investigate whether vitamin D supplementation during infancy is associated with diabetes-related autoimmunity at 1 and 2.5 yr in the children. Second, we examined whether consumption of vitamin-D-containing supplements during pregnancy is related to risk of autoimmunity in the offspring. Screening questionnaires were completed for 16,070 infants after delivery, including a food-frequency questionnaire regarding the mother's use of dietary supplements during pregnancy. Parents of 11,081 and 8805 infants completed a follow-up questionnaire regarding the use of vitamin supplementation at 1 and 2.5 yr, respectively. Autoantibodies against glutamic acid decarboxylase and islet antigen-2 (IA-2) were analyzed in whole blood from 8694 children at 1 yr and 7766 children at 2.5 yr. Supplementation with AD-drops was not associated with autoantibodies at 1 or 2.5 yr. Use of vitamin-D-containing supplements during pregnancy was associated with reduced diabetes-related autoimmunity at 1 yr (adjusted odds ratio: 0.707, confidence interval: 0.520-0.962, p = 0.028) but not at 2.5 yr. In conclusion, no association was found between an intermediate dose of vitamin D supplementation during infancy and development of diabetes-related autoantibodies at 1 and 2.5 yr. Use of vitamin-D-containing supplements during pregnancy was associated with reduced development of glutamic acid decarboxylase autoantibodies or IA-2A in the offspring at 1 yr, but not at 2.5 yr.

Vitamin D supplement in early childhood and risk for Type I (insulin-dependent) diabetes mellitus. The EURODIAB Substudy 2 Study Group.
            (1999) Download
The initiation of the immunopathogenetic process that can lead to Type I (insulin-dependent) diabetes mellitus in childhood probably occurs early in life. Studies in vitro have shown that vitamin D3 is immunosuppressive or immunomodulating and studies in experimental models of autoimmunity, including one for autoimmune diabetes, have shown vitamin D to be protective. Seven centres in Europe with access to population-based and validated case registers of insulin-dependent diabetes patients participated in a case-control study focusing on early exposures and risk of Type I diabetes. Altogether data from 820 patients and 2335 control subjects corresponding to 85% of eligible patients and 76% of eligible control subjects were analysed. Questions focused on perinatal events and early eating habits including vitamin D supplementation. The frequency of vitamin D supplementation in different countries varied from 47 to 97% among control subjects. Vitamin D supplementation was associated with a decreased risk of Type I diabetes without indication of heterogeneity. The Mantel-Haenszel combined odds ratio was 0.67 (95% confidence limits: 0.53, 0.86). Adjustment for the possible confounders: a low birth weight, a short duration of breast feeding, old maternal age and study centre in logistic regression analysis did not affect the significant protective effect of vitamin D. In conclusion, this large multicentre trial covering many different European settings consistently showed a protective effect of vitamin D supplementation in infancy. The findings indicate that activated vitamin D might contribute to immune modulation and thereby protect or arrest an ongoing immune process initiated in susceptible people by early environmental exposures.


 

The importance of vitamin C for hydroxylation of vitamin D3 to 1,25(OH)2D3 in man.
            (Cantatore et al., 1991) Download
The effects of vitamin C on 1,25(OH)2D3 synthesis in humans were evaluated; the study included 20 females. They were divided into 2 groups. The first of the 10 subjects (age range 55-71) received ascorbic acid at a dose of 150 mg/die i.v. for 10 days; the second 10 subjects (age range 55-69) received a placebo i.v. for 10 days. In a later study (after a 30-day washout) the same two groups were tested for the second time with ascorbic acid at a dose of 1,000 mg/die i.v. for 10 days and placebo i.v. for 10 days. Serum calcium and phosphorus, serum Ca++, serum proteins, blood and urinary pH, serum 25(OH)D3 and 1,25(OH)2D3, serum PTH, urinary hydroxyprolin were tested before and after the treatments. In the first study a significant increase in serum 1,25(OH)2D3 was observed after ascorbic acid while no significant variation was observed for the other parameters. In the second study, a significant increase in serum Ca++ and a significant decrease in serum 1,25(OH)2D3 were observed after ascorbic acid while no significant variation was observed for the other parameters. The authors conclude that ascorbic acid promotes 1,25(OH)2D3 synthesis at a paraphysiologic dose (150 mg/die) in humans but this synthesis is inhibited at higher doses (1,000 mg/die). The latter effect by Ca++ or by an effect of ascorbate on 1 alpha-hydroxylase enzyme could be mediated.

25-Hydroxyvitamin D is closely related with the function of the pancreatic islet beta cells
            (Guo et al., 2013) Download
Objectives: This study is to investigate the relationship between 25-Hydroxyvitamin D (25-OH-D) and pancreatic islet beta cell function under different glucose tolerance statuses in China. Methodology: Totally, 180 patients with type 2 diabetes mellitus (DM group), 178 patients with impaired fasting glucose/impaired glucose tolerance (IFG/IGT group), and 160 normal control subjects (NGT group) were included to measure their body parameters and biochemical parameters. In oral glucose tolerance test, fasting serum 25-OH-D was assessed by the enzyme-linked immunosorbent assay (ELISA). Homeostasis model assessment for insulin resistance (Homa-IR), insulin acuity index (IAI), beta-cell function index (Homa-BCF) as well as secretion index (IS) were determined. Results: The levels of 25-OH-D, IAI and Homa-BCF in the DM group and IFG/IGT group were significantly lower than that in NGT group (P < 0.05). Homa-IR in DM group and IFG/IGT group was significantly higher than that in the NGT group (P < 0.05). Pearson correlation analysis and partial correlation analysis showed that 25-OH-D was positively correlated with fasting insulin (FINS) and Homa-BCF (P < 0.05). Multiple stepwise regression analysis showed that 25-OH-D was one of the influential factors of pancreatic islet beta cell function in patients with type 2 diabetes mellitus. Conclusions: Our results suggest that 25-OH-D is closely related with the function of the pancreatic islet beta cells and is one of the influential factors of pancreatic islet beta cell function.

 

Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study.
            (Hyppönen et al., 2001) Download
BACKGROUND:  Dietary vitamin D supplementation is associated with reduced risk of type 1 diabetes in animals. Our aim was to ascertain whether or not vitamin D supplementation or deficiency in infancy could affect development of type 1 diabetes. METHODS:  A birth-cohort study was done, in which all pregnant women (n=12055) in Oulu and Lapland, northern Finland, who were due to give birth in 1966 were enrolled. Data was collected in the first year of life about frequency and dose of vitamin D supplementation and presence of suspected rickets. Our primary outcome measure was diagnosis of type 1 diabetes by end of December, 1997. FINDINGS:  12058 of 12231 represented live births, and 10821 (91% of those alive) children were followed-up at age 1 year. Of the 10366 children included in analyses, 81 were diagnosed with diabetes during the study. Vitamin D supplementation was associated with a decreased frequency of type 1 diabetes when adjusted for neonatal, anthropometric, and social characteristics (rate ratio [RR] for regular vs no supplementation 0.12, 95% CI 0.03-0.51, and irregular vs no supplementation 0.16, 0.04-0.74. Children who regularly took the recommended dose of vitamin D (2000 IU daily) had a RR of 0.22 (0.05-0.89) compared with those who regularly received less than the recommended amount. Children suspected of having rickets during the first year of life had a RR of 3.0 (1.0-9.0) compared with those without such a suspicion. INTERPRETATION:  Dietary vitamin D supplementation is associated with reduced risk of type 1 diabetes. Ensuring adequate vitamin D supplementation for infants could help to reverse the increasing trend in the incidence of type 1 diabetes.

Calcium Homeostasis During Attack and Remission in Patients With Idiopathic Benign Paroxysmal Positional Vertigo.
            (Kahraman et al., 2016) Download
OBJECTIVE:  To evaluate changes in calcium metabolism in patients with idiopathic benign paroxysmal positional vertigo (BPPV) on initial presentation and at the follow-up visit. SUBJECTS AND METHODS:  The study comprised a total of 31 patients aged greater than 18 years who presented at the otorhinolaryngology outpatient clinic of our hospital, newly diagnosed as idiopathic BPPV based on the history compatible with BPPV and positive provocative maneuver (either Dix-Hallpike or Roll test). The first blood sample was obtained on the day of initial presentation when the patient was found to have active unilateral BPPV. After 6 months, a blood sample was again drawn in accordance with the procedure. Blood samples were analyzed for data on 25-hydroxyvitamin D (25(OH)-D), total calcium, parathormone and ionized calcium on initial presentation, and at the follow-up visit. RESULTS:  The patients comprised 20 (64.5%) women and 11 (35.5%) men with a mean age of 49.78 years (range, 23-75 years). During an attack a higher prevalence of decreased serum Vitamin D is less than 20 ng/ml, was determined (93.5% versus 38.7%). There were statistical differences between the Vitamin D values, parathormone, and corrected by pH ionized calcium in both periods (p < 0.05). CONCLUSION:  A statistically significant association was determined between Vitamin D and calcium metabolism in patients with idiopathic BPPV. It can be considered that Vitamin D deficiency and decreased ionized Ca level may be a risk for BPPV, not only in patients with osteoporosis but also in all patients. Very low levels of 25(OH)-D seem to be associated with recurrence of BPPV. The recurrences might possibly be prevented with supplementary Vitamin D especially in those with recurrent idiopathic BPPV but further studies would be necessary to determine this.

An increase in serum 25-hydroxyvitamin D concentrations preceded a plateau in type 1 diabetes incidence in Finnish children.
            (Mäkinen et al., 2014) Download
CONTEXT:  In Finland the world-record for the highest incidence of type 1 diabetes has risen steeply over the past decades. However, after 2006 the incidence rate has plateaued. We showed earlier, that despite the strong genetic disease component, environmental factors are driving the increasing disease incidence. OBJECTIVE:  Since vitamin D intake has increased considerably in the country since 2003, we analyzed how serum 25-hydroxyvitamin D (25[OH]D) concentration changed over time in healthy children, and the timely relation of these changes to disease incidence. DESIGN, SETTING AND PARTICIPANTS:  The birth cohort of the Finnish Type 1 Diabetes Prediction and Prevention project was used to explore longitudinal changes in serum 25-hydroxyvitamin concentrations. The sampling period was limited to children born from 1994 to 2004, with serum samples collected during 1998-2006 in the Turku area, Southwest Finland (60 °N). MAIN OUTCOME MEASURE:  25(OH)D concentrations were measured every 3-6 months from birth, ages ranging from 0.3 to 12.2 years (387 subjects, 5334 measurements). RESULTS:  Serum 25(OH)D concentrations were markedly lower before 2003 than after (69.3 ± 1.0 nmol/L vs 84.9 ± 1.3 nmol/L, respectively, P < .001) in both genders. The mean difference between the periods was 15.7 ± 1.3 nmol/L (P < .001). Importantly, the frequency of children with low serum 25(OH)D levels (< 50 nmol/L) was reduced to almost half from 2003 (37.3% vs 69.9 %; P < .001). Similarly, severe vitamin D deficiency (<25 nmol/L) also decreased (2.7% vs 7.7%; P = .005). In addition, we detected higher 25(OH)D concentrations in young children (< 2 years) as compared to older children, which is explained by higher vitamin D intake in this group. CONCLUSIONS:  We provide evidence that an increase in circulating concentrations of 25(OH)D shows a delayed temporal association with leveling off of type 1 diabetes incidence in Finland after 2006.

 

Serum 25-Hydroxyvitamin D Concentrations in Children Progressing to Autoimmunity and Clinical Type 1 Diabetes.
            (Mäkinen et al., 2016) Download
CONTEXT:  The role of vitamin D in the development of type 1 diabetes (T1D) remains controversial. OBJECTIVE:  The objective of the investigation was to study whether there are detectable differences in serum 25-hydroxyvitamin D (25[OH]D) concentrations between children who later progressed to T1D (cases) and matched children who remained nondiabetic and negative for islet autoantibodies (controls) when followed up from birth until disease onset. DESIGN:  A total of 3702 prospective serum samples from 252 children were measured for 25(OH)D from the age of 3 months onward using an enzyme immunoassay. Differences between the groups were compared by the mixed-model analysis of variance. SETTING:  T1D prediction and prevention study clinics in Turku, Oulu, and Tampere University Hospitals, Finland, participated in the study. PARTICIPANTS:  By the end of 2012, all 126 case children were diagnosed with T1D. The control children (n = 126) were matched for age, sex, study site, and human leukocyte antigen-HLA-DQ-conferred risk for T1D. MAIN OUTCOME MEASURE:  Median circulating 25(OH)D concentration (nanomoles per liter) was measured. RESULTS:  The patterns of variation in circulating 25(OH)D concentrations were similar between cases and controls and did not correlate with the age at seroconversion to autoantibody positivity (P = .79) or disease onset (P = .13). The median concentration of all collected samples did not differ between case and control children (66.6 nmol/L [range 14.0-262.8] vs 67.4 nmol/L [range 19.9-213.0]) P = .56). CONCLUSIONS:  This study shows that serum 25(OH)D concentrations are not associated with the development of T1D in Finland.

Preclinical serum 25-hydroxyvitamin D levels and risk of type 1 diabetes in a cohort of US military personnel
            (Munger et al., 2013) Download
To determine whether serum levels of 25-hydroxyvitamin D (25(OH)D) in young adults are associated with risk of type 1 diabetes mellitus (T1D), we conducted a prospective, nested case-control study among US active-duty military personnel with serum in the US Department of Defense Serum Repository, identifying 310 T1D cases diagnosed between 1997 and 2009 with at least 2 serum samples collected before disease onset and 613 controls matched to cases on age, sex, race/ethnicity, branch of military service, and dates of serum collection. Conditional logistic regression was used to estimate rate ratios and 95% confidence intervals. Among non-Hispanic whites, those with average 25(OH)D levels of >/= 100 nmol/L had a 44% lower risk of developing T1D than those with average 25(OH)D levels < 75 nmol/L (rate ratio = 0.56, 95% confidence interval: 0.35, 0.90, P for trend = 0.03) over an average follow-up of 5.4 years. In quintile analyses, T1D risk was highest among individuals whose 25(OH)D levels were in the lowest 20% of those measured. There was no association between 25(OH)D levels and risk of T1D among non-Hispanic blacks or Hispanics. Low 25(OH)D levels may predispose healthy, young, non-Hispanic white adults to the development of T1D.

Calcitriol/calcifediol ratio: An indicator of vitamin D hydroxylation efficiency
            (Pasquali et al., 2015) Download
BACKGROUND:  Calcifediol (25D) availability is crucial for calcitriol (1,25D) synthesis, but regulation of vitamin D hydroxylases is majorly responsible for 1,25D synthesis. The net efficiency of vitamin D hydroxylases might be informative. We assume that the ratio between calcitriol and calcifediol (25D/1,25D) serum concentrations could suggest the vitamin D hydroxylation efficiency. METHODS:  We evaluated 25D/1,25D in different patient populations: hemodialysis (HD, n = 76), CKD stage 2-5 (n = 111), renal transplant (TX, n = 135), patients with no renal disease (No-CKD, n = 290), and primary hyperparathyroidism (PHP, n = 20). RESULTS:  The geometric mean of 1,25D/25D (pg/ng) averaged 1.11 (HD), 1.36 (CKD), 1.77 (TX), 2.22 (No-CKD), and 4.11 (PHP), with a progressive increment from HD to PHP (p-value for the trend <0.001). Each clinical condition elicited a significant effect on 25D/1,25D (p < 0.0001) and adjusted multivariate analysis indicated levels of Cas, Ps, PTH, and 25D as predictors of 25D/1,25D. Both in vitamin D deficient and replete subjects (25D< or ≥20 ng/ml) 25D/1,25D associated with each clinical condition (p < 0.0001) and mean values increased progressively from HD to PHP (p-values for the trend <0.0001). Regression analysis between 25D (substrate) and 25D/1,25D (efficiency) revealed an exponential negative correlation in No-CKD (r(2)Exp = 0.53, p < 0.001) with sharp increments of 25D/1,25D when 25D values are <20 ng/ml. At variance, in CKD (r(2)lin = 0.19) and in TX (r(2)lin = 0.32) the regression was linear as if, in case of deficit, some inhibition of the system were operating. CONCLUSION AND GENERAL SIGNIFICANCE:  In conclusion 1,25D/25D can reflect the efficiency of vitamin D hydroxylases more than separate evaluation of 25D and 1,25D and can facilitate the therapeutic choices in different patient populations.

Influence of supplemental vitamin D on intensity of benign paroxysmal positional vertigo: A longitudinal clinical study.
            (Sheikhzadeh et al., 2016b) Download
BACKGROUND:  Benign paroxysmal positional vertigo (BPPV) is linked to vitamin D deficiency. This clinical trial aimed to determine the influence of vitamin D supplementation on intensity of BPPV. METHODS:  The study population was selected consecutively and the diagnosis of BPPV was made by history and clinical examination and exclusion of other conditions. Intensity of BPVV was assessed based on VAS score (0-10). Serum 25-hydroxyvitamin D (25-OHD) was measured using ELISA method and levels < 20 ng/ml was considered a deficiency. All patients received rehabilitation treatment using Epley's maneuver one time per week for one month. Serum 25-OHD deficient patients were classified as treated and non-treated groups (rehabilitation with or without 50.000 IU cholecalciferol weekly for two months).The results of treatment were compared with vitamin D sufficient group as control. All patients were followed-up for 6 months. RESULTS:  After two months of treatment, in both vitamin D treated and non-treated groups the intensity of BPPV decreased significantly as compared with control (P=0.001 for both groups) but at endpoint, the intensity of BPPV aggravated and regressed to the baseline value in vitamin D deficient non-treated group (P=0.001) whereas, in vitamin D treated group, improvement of BPPV remained stable and unchanged over the study period. CONCLUSION:  This study indicates that correction of vitamin D deficiency in BPPV provides additional benefit to rehabilitation therapy (Epley maneuver) regarding duration of improvement. These findings suggest serum 25-OHD measurement in recurrent BPPV.

The effect of serum vitamin D normalization in preventing recurrences of benign paroxysmal positional vertigo: A case-control study.
            (Sheikhzadeh et al., 2016a) Download
BACKGROUND:  Benign paroxysmal positional vertigo (BPPV) is a condition with recurrent attacks in a significant proportion of patients. The present case- control study was conducted to assess the influence of serum vitamin D normalization on recurrent attacks of vitamin D deficient patients. METHODS:  Diagnosis of BPPV was made based on history and clinical examination and exclusion of other conditions. Serum 25-hydroxy vitamin D (25-OHD) was measured using ELISA method and a levels of < 20 ng/ml was considered a deficiency of vitamin D. Inclusion criteria were as follows: history of recurrent attacks and serum 25-OHD<20.ng/ml. While the patients with history of trauma, surgery and chronic systemic diseases were excluded. The patients were classified into two groups: treatment and control, intermittently. Both groups received Epley rehabilitation therapy one session per week for 4 weeks but the treatment group received an additional supplement of 50.000 IU of vitamin D (cholecalciferol) weekly for two months to achieve serum 25-OHD ≥ 30 ng/ml and the study patients were followed-up for 6 months. RESULTS:  Twenty-seven patients were allocated to each group. At baseline, serum 25-OHD was similar (10.7±2.3 vs 11.41±1.9, P=0.23). At month 2, serum 25-OHD in the treatment group increased significantly to ≥ 30 ng/ ml, whereas serum 25-OHD in the control group remained unchanged (34.2±3.3 vs 10.6 10.6±2.2 ng/ml, P=0.001). During the follow-up period, attacks of BPPV in the treatment group decreased significantly compared with the control group (14.8% vs 96.3% OR= 0.18, P=0.001). CONCLUSION:  The findings of this study indicate that the normalization of serum vitamin D significantly reduces BPPV recurrences.

Low bone mineral density and vitamin D deficiency in patients with benign positional paroxysmal vertigo.
            (Talaat et al., 2015) Download
Several studies indicated the association between benign paroxysmal positional vertigo (BPPV) with osteoporosis and vitamin D deficiency implying that abnormal calcium metabolism may underlie BPPV. The aim of the present study is to confirm the correlation between BPPV and both decrease in bone mineral density (BMD) and vitamin D deficiency. The study group included 80 patients with idiopathic BPPV (52 females, 28 males), with age range 31-71 years (47.6 ± 9.1). The patients were divided into two groups; recurrent BPPV group including 36 subjects and non-recurrent group including 44 subjects. The control group included 100 healthy volunteers with age and gender distribution similar to the study group. All the subjects in the study were examined using Dual-energy X-ray absorptiometry to assess BMD, and serum 25-hydroxyvitamin D for vitamin D assessment. The accepted normal levels were T-score > -1, and 25-hydroxyvitamin D > 30 ng/ml. Twenty-six (26 %) subjects showed abnormal T-score in the control group; 26 (59 %) in the non-recurrent BPPV and 22 (61 %) in the recurrent BPPV group. Chi square test showed significant difference between the control group and both BPPV groups. The control group had significantly higher 25-hydroxyvitamin D levels than the BPPV subgroups (p < 0.05). Moreover, the 25-hydroxyvitamin D was significantly lower in the recurrent BPPV than it was in the non-recurrent subgroup (p < 0.05). The results of the current study associate between reduced BMD and development/recurrence of BPPV. Moreover, low levels of vitamin D were related to development of BPPV while very low levels were associated with recurrence of BPPV. The co-occurrence of two morbidities is not by itself supportive of a relationship, but the cumulating studies correlating between BPPV and both vitamin D deficiency and low BMD indicate the investigation and treatment of those disorders in cases with recurrent BPPV.


Reduction of recurrence rate of benign paroxysmal positional vertigo by treatment of severe vitamin D deficiency.
            (Talaat et al., 2016) Download
OBJECTIVE:  Several studies correlated between vitamin D deficiency and the development, and the recurrence of benign positional paroxysmal vertigo (BPPV), but none of them proved that treatment of vitamin D deficiency would reduce the recurrence rate of BPPV. This study aims to detect the effect of treatment of severe vitamin D deficiency on the recurrence rate of BPPV. METHODS:  The inclusion criteria of the study group were: (1) Unilateral, idiopathic, posterior canal BPPV with no history suggestive of secondary BPPV and (2) 25-hydroxyvitamin D3 level ≤10 ng/ml. All subjects enrolled in the current study underwent detailed clinical history, audiovestibular evaluation consisting of pure-tone audiometry, Immittancemetry, Videonystugmography, serum 25-hydroxyvitamin D3 assessment, and Dual-energy X-ray absorptiometry (DXA). Vitamin D therapy was prescribed for the study group. Serum 25-hydroxyvitamin D3 level was evaluated twice, on recruitment into the study group and 3 months after commencing vitamin D therapy. According to the results of the second evaluation of serum 25-hydroxyvitamin D3, the study group was subdivided into two subgroups: Subgroup (I): including 28 subjects who disclosed elevation of serum 25-hydroxyvitamin D3 level; improvement ≥10 ng/ml. Subgroup (II): including 65 patients who disclosed elevation of serum 25-hydroxyvitamin D3 levels <10 ng/ml. The study group was followed up for 18 months in order to observe the recurrence of BPPV. RESULTS:  The differences between both study subgroups (I) & (II) regarding age, sex distribution, and bone mineral density were insignificant. The number of subjects who had recurrence of BPPV in subgroup (I) was 4 (14%) versus 28 subjects (43%) in subgroup (II). The mean values for recurrent attacks/subject in subgroups (I) & (II) were 0.18, and 0.66 attack/subject respectively; these differences between both subgroups were of high statistical significance (p<0.01). The Odds Ratio for development of recurrence of BPPV in subjects with severe vitamin D deficiency was 4.54 (95% CI: 1.41-14.58, p<0.01). The relapse attacks of BPPV affected both ears irrespective of the ear showing the original BPPV attack. CONCLUSION:  The present study indicates that improvement of serum 25-hydroxyvitamin D3 levels is associated with substantial decrease in recurrence of BPPV.

Vitamin D supplementation in early childhood and risk of type 1 diabetes: a systematic review and meta-analysis.
            (Zipitis and Akobeng, 2008) Download
OBJECTIVES:  To assess whether vitamin D supplementation in infancy reduces the risk of type 1 diabetes in later life. METHODS:  This was a systematic review and meta-analysis using Medline, Embase, Cinahl, Cochrane Central Register of Controlled Trials and reference lists of retrieved articles. The main outcome measure was development of type 1 diabetes. Controlled trials and observational studies that had assessed the effect of vitamin D supplementation on risk of developing type 1 diabetes were included in the analysis. RESULTS:  Five observational studies (four case-control studies and one cohort study) met the inclusion criteria; no randomised controlled trials were found. Meta-analysis of data from the case-control studies showed that the risk of type 1 diabetes was significantly reduced in infants who were supplemented with vitamin D compared to those who were not supplemented (pooled odds ratio 0.71, 95% CI 0.60 to 0.84). The result of the cohort study was in agreement with that of the meta-analysis. There was also some evidence of a dose-response effect, with those using higher amounts of vitamin D being at lower risk of developing type 1 diabetes. Finally, there was a suggestion that the timing of supplementation might also be important for the subsequent development of type 1 diabetes. CONCLUSION:  Vitamin D supplementation in early childhood may offer protection against the development of type 1 diabetes. The evidence for this is based on observational studies. Adequately powered, randomised controlled trials with long periods of follow-up are needed to establish causality and the best formulation, dose, duration and period of supplementation.

 


References

Brar, PC, et al. (2018), ‘Effect of one time high dose “stoss therapy” of vitamin D on glucose homeostasis in high risk obese adolescents.’, Arch Endocrinol Metab, 62 (2), 193-200. PubMed: 29641737
Brekke, HK and J Ludvigsson (2007), ‘Vitamin D supplementation and diabetes-related autoimmunity in the ABIS study.’, Pediatr Diabetes, 8 (1), 11-14. PubMed: 17341286
Cantatore, FP, et al. (1991), ‘The importance of vitamin C for hydroxylation of vitamin D3 to 1,25(OH)2D3 in man.’, Clin Rheumatol, 10 (2), 162-67. PubMed: 1655350
Guo, J., et al. (2013), ‘25-Hydroxyvitamin D is closely related with the function of the pancreatic islet beta cells’, Pak J Med Sci, 29 (3), 809-13. PubMed: 24353633
Hyppönen, E, et al. (2001), ‘Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study.’, Lancet, 358 (9292), 1500-3. PubMed: 11705562
Kahraman, SS, et al. (2016), ‘Calcium Homeostasis During Attack and Remission in Patients With Idiopathic Benign Paroxysmal Positional Vertigo.’, Otol Neurotol, 37 (9), 1388-92. PubMed: 27525708
Mäkinen, M, et al. (2014), ‘An increase in serum 25-hydroxyvitamin D concentrations preceded a plateau in type 1 diabetes incidence in Finnish children.’, J Clin Endocrinol Metab, 99 (11), E2353-6. PubMed: 25062454
Mäkinen, M, et al. (2016), ‘Serum 25-Hydroxyvitamin D Concentrations in Children Progressing to Autoimmunity and Clinical Type 1 Diabetes.’, J Clin Endocrinol Metab, 101 (2), 723-29. PubMed: 26695863
Munger, K. L., et al. (2013), ‘Preclinical serum 25-hydroxyvitamin D levels and risk of type 1 diabetes in a cohort of US military personnel’, Am J Epidemiol, 177 (5), 411-19. PubMed: 23380046
Pasquali, M, et al. (2015), ‘Calcitriol/calcifediol ratio: An indicator of vitamin D hydroxylation efficiency’, BBA Clin, 3 251-56. PubMed: 26676064
Sheikhzadeh, M, et al. (2016a), ‘The effect of serum vitamin D normalization in preventing recurrences of benign paroxysmal positional vertigo: A case-control study.’, Caspian J Intern Med, 7 (3), 173-77. PubMed: 27757201
Sheikhzadeh, M, et al. (2016b), ‘Influence of supplemental vitamin D on intensity of benign paroxysmal positional vertigo: A longitudinal clinical study.’, Caspian J Intern Med, 7 (2), 93-98. PubMed: 27386060
Talaat, HS, et al. (2015), ‘Low bone mineral density and vitamin D deficiency in patients with benign positional paroxysmal vertigo.’, Eur Arch Otorhinolaryngol, 272 (9), 2249-53. PubMed: 24973969
Talaat, HS, et al. (2016), ‘Reduction of recurrence rate of benign paroxysmal positional vertigo by treatment of severe vitamin D deficiency.’, Auris Nasus Larynx, 43 (3), 237-41. PubMed: 26386496
(1999), ‘Vitamin D supplement in early childhood and risk for Type I (insulin-dependent) diabetes mellitus. The EURODIAB Substudy 2 Study Group.’, Diabetologia, 42 (1), 51-54. PubMed: 10027578
Zipitis, CS and AK Akobeng (2008), ‘Vitamin D supplementation in early childhood and risk of type 1 diabetes: a systematic review and meta-analysis.’, Arch Dis Child, 93 (6), 512-17. PubMed: 18339654