Vitamin D deficiency

Serum 25-hydroxyvitamin d levels are not associated with subclinical vascular disease or C-reactive protein in the old order amish

The relationship between vitamin D metabolites and subclinical vascular disease is controversial. Because low serum levels of 25-hydroxyvitamin D (25(OH)D) have been associated with many cardiovascular disease (CVD) risk factors, we hypothesized that serum 25(OH)D levels would be inversely associated with inflammation as measured by C-reactive protein (CRP) and with subclinical vascular disease as measured by carotid intimal medial thickness (cIMT) and coronary artery calcification (CAC). We measured 25(OH)D levels in 650 Amish participants. CAC was measured by computed tomography and cIMT by ultrasound. The associations of 25(OH)D levels with natural log(CAC + 1), cIMT, and natural log(CRP) levels were estimated after adjustment for age, sex, family structure, and season of examination. Additional analyses were carried out adjusting for body mass index (BMI) and other CVD risk factors. 25(OH)D deficiency (<20 ng/ml) and insufficiency (21-30 ng/ml) were common among the Amish (38.2% and 47.7%, respectively). 25(OH)D levels were associated with season, age, BMI, and parathyroid hormone levels. In neither the minimally or fully adjusted analyses were significant correlations observed between 25(OH)D levels and CAC, cIMT, or CRP (R (2) < 0.01 for all). Contrary to our hypothesis, this study failed to detect a cross-sectional association between serum 25(OH)D levels and CAC, cIMT, or CRP. Either there is no causal relationship between 25(OH)D and CVD risk, or if there is, it may be mediated through mechanisms other than subclinical vascular disease severity.

Implications of a new definition of vitamin D deficiency in a multiracial us adolescent population: the National Health and Nutrition Examination Survey III

OBJECTIVE

In children, vitamin D deficiency can interfere with bone mineralization, leading to rickets. In adults, it is linked to cardiovascular disease, insulin resistance, and hypertension. Accurate estimates of the prevalence of vitamin D deficiency are complicated by the lack of consensus as to optimal vitamin D status. Currently, individuals with serum 25-hydroxyvitamin D levels of <11 ng/mL are classified as vitamin D deficient. Experts collectively have proposed that minimum levels be at least 20 ng/mL. Our objectives were to (1) determine the national prevalence of vitamin D deficiency in adolescents by using both the current and recommended cutoffs and (2) examine the implications of the new recommendation after adjustment for various factors.

METHODS

Data were obtained from National Health and Nutrition Examination Survey III, a cross-sectional survey administered to a nationally representative sample of noninstitutionalized civilians aged 2 months and older. Analyses were restricted to 2955 participants aged 12 to 19 with serum 25-hydroxyvitamin D levels. Relationships between serum 25-hydroxyvitamin D levels and sociodemographic variables were evaluated by using logistic regression.

RESULTS

Changing the definition of vitamin D deficiency from <11 to <20 ng/mL increased the prevalence from 2% to 14%. After adjustment for all covariates, non-Hispanic black adolescents had 20 times the risk of serum 25-hydroxyvitamin D <20 ng/mL compared with non-Hispanic white adolescents. The risk of deficiency was more than double for females compared with males. An inverse relationship between weight and serum 25-hydroxyvitamin D levels was found. Overweight adolescents had increased risk of deficiency compared with normal-weight adolescents.

CONCLUSIONS

There was a disproportionate burden of vitamin D deficiency in the non-Hispanic black adolescent population. Routine supplementation and monitoring of serum levels should be considered. Females and overweight adolescents are at increased risk. The consequences of chronic vitamin D deficiency in adolescents should be prospectively investigated.

Vitamin D deficiency in patients with active systemic lupus erythematosus

We investigated the effects of disease activity on bone metabolism in 36 patients with systemic lupus erythematosus (SLE). Changes in bone remodeling were not explained by corticosteroid use. A high prevalence of 25OHD deficiency in SLE patients indicates the need for vitamin D replacement, mainly during high disease activity periods.

INTRODUCTION

We investigated the effects of SLE disease activity on bone metabolism, their relation to inflammatory cytokines and vitamin D levels.

METHODS

We performed a cross-sectional analysis of 36 SLE patients classified according to the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) in high activity (group I: 12 patients, mean age 29.6 years) or in minimal activity (group II: 24 patients, mean age 30.0 years), and compared them to normal controls (group III: 26 women, 32.8 years). Serum calcium, phosphorus, parathyroid and sex hormones, bone remodeling markers, interleukin (IL)-6, soluble IL-6 receptor (sIL-6R), IL-1, tumor necrosis factor-alpha (TNF), 25-hydroxivitamin D (25OHD), and 1,25-dihydroxyvitamin D3 were measured, plus bone mineral density.

RESULTS

All cytokines were significantly higher in SLE groups; IL-6 could differentiate SLE patients from controls. In group I, 25OHD levels were lower (P < 0.05), which was related to the SLEDAI (R = -0.65, P < 0.001). In multiple regression analysis, the 25OHD level was associated with SLEDAI, osteocalcin and bone-specific alkaline phosphatase. The SLEDAI score was positively correlated with all measured cytokines and especially TNF (R = 0.75, P < 0.001).

CONCLUSIONS

SLE patients demonstrated changes in bone remodeling strongly related to disease activity. A high prevalence of 25OHD deficiency was observed in SLE patients, indicating the need for vitamin D replacement.

Evaluation of vitamin D repletion regimens to correct vitamin D status in adults

OBJECTIVE

To determine the efficacy and safety of commonly prescribed regimens for the treatment of vitamin D insufficiency.

METHODS

We performed a retrospective analysis of 306 consecutive patients who were prescribed ergocalciferol (vitamin D2) for correction of vitamin D insufficiency at the Atlanta Veterans Affairs Medical Center between February 2003 and May 2006. Serum levels of parathyroid hormone, 25-hydroxyvitamin D (25-OHD), and calcium were compared before and after treatment with ergocalciferol. Patients who did not have a 25-OHD determination (n = 41) were excluded from analysis. Vitamin D deficiency, insufficiency, and sufficiency were defined as a serum 25-OHD level of <20 ng/mL, 21 to 29 ng/mL, and > or =30 ng/mL, respectively.

RESULTS

We identified 36 discrete prescribing regimens. The 3 most common regimens were ergocalciferol 50,000 IU once weekly for 4 weeks followed by 50,000 IU once monthly for 5 months (n = 48); ergocalciferol 50,000 IU once monthly for 6 months (n = 80); and ergocalciferol 50,000 IU 3 times weekly for 6 weeks (n = 27). Each of these 3 treatments significantly increased serum 25-OHD (P<.01), but vitamin D sufficiency was achieved in only 38%, 42%, and 82% of study subjects, respectively. Regimens with >600,000 IU of ergocalciferol given for a mean of 60 +/- 40 days achieved sufficiency in 64% of cases, without vitamin D toxicity.

CONCLUSION

In this study, regimens that contained at least 600,000 IU of ergocalciferol appeared to be the most effective in achieving vitamin D sufficiency. Guidelines for the treatment of vitamin D insufficiency in healthy adults should be developed.

Association between vitamin D deficiency and primary cesarean section

BACKGROUND

At the turn of the 20th century, women commonly died in childbirth due to rachitic pelvis. Although rickets virtually disappeared with the discovery of the hormone vitamin D, recent reports suggest vitamin D deficiency is widespread in industrialized nations. Poor muscular performance is an established symptom of vitamin D deficiency. The current U.S. cesarean birth rate is at an all-time high of 30.2%. We analyzed the relationship between maternal serum 25-hydroxyvitamin D [25(OH)D] status, and prevalence of primary cesarean section.

METHODS

Between 2005 and 2007, we measured maternal and infant serum 25(OH)D at birth and abstracted demographic and medical data from the maternal medical record at an urban teaching hospital (Boston, MA) with 2500 births per year. We enrolled 253 women, of whom 43 (17%) had a primary cesarean.

RESULTS

There was an inverse association with having a cesarean section and serum 25(OH)D levels. We found that 28% of women with serum 25(OH)D less than 37.5 nmol/liter had a cesarean section, compared with only 14% of women with 25(OH)D 37.5nmol/liter or greater (P = 0.012). In multivariable logistic regression analysis controlling for race, age, education level, insurance status, and alcohol use, women with 25(OH)D less than 37.5 nmol/liter were almost 4 times as likely to have a cesarean than women with 25(OH)D 37.5 nmol/liter or greater (adjusted odds ratio 3.84; 95% confidence interval 1.71 to 8.62).

CONCLUSION

Vitamin D deficiency was associated with increased odds of primary cesarean section.

Vitamin D: a D-Lightful health perspective

Sunlight provides most humans with their vitamin D requirement. Adequate vitamin D(3) by synthesis in the skin or from dietary and supplemental sources is essential for bone health throughout life. Vitamin D deficiency is defined as a 25(OH)D concentration <20 ng/mL (50 nmol/L); vitamin D sufficiency as a 25(OH)D >30 ng/mL (75 nmol/L), and insufficiency as 21-29 ng/mL. Vitamin D deficiency and insufficiency has been linked to a wide variety of chronic diseases including common cancers, autoimmune, cardiovascular, and infectious diseases. Healthcare professionals need to be aware of the vitamin D deficiency pandemic. Guidelines for sensible sun exposure and supplemental vitamin D of 800-1000 IU/day are needed.

Gestational vitamin D deficiency: long-term effects on the brain

Gestational vitamin D deficiency causes permanent changes in the developing rat brain. Not only does it alter brain gene and protein expression, deficiency disrupts the balance between neuronal stem cell proliferation and programmed cell death in the offspring. These data are particularly relevant in light of new work showing a high prevalence of vitamin D deficiency in humans.

A sensitive LC/MS/MS assay of 25OH vitamin D3 and 25OH vitamin D2 in dried blood spots

BACKGROUND

Low levels of 25 hydroxyvitamin D (25OHD) during early development is associated with a range of adverse health outcomes. While a number of methods exist to measure 25OHD in sera, none have been specifically developed to examine dried blood spots (DBS).

METHODS

We describe an assay where 25 hydroxyvitamin D(3) (25OHD3) and 25 hydroxyvitamin D(2) (25OHD2) are extracted from 3.2 mm DBS punches, derivatised with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) prior to analysis with LC/MS/MS. We assessed assay precision, relative accuracy and examined the impact of storage conditions in samples stored for up to 22 years.

RESULTS

The new assay had good accuracy and precision, and was highly sensitive, being capable of detecting <1 nmol/l 25OHD3 and 2 nmol/l 25OHD2. CDER sensitivity criteria were slightly higher at 7.7 nmol/l for 25OHD3 and 10.7 nmol/l for 25OHD2. The mean 25OHD3 concentration in 118 archived DBS was 20.8+/-11.4, (4.8 to 67.8 nmol/l). 25OHD2 was detected in only two of these samples. 25OHD3 concentrations were significantly higher in DBS collected in summer compared to winter (p<0.0001).

CONCLUSION

Both 25OHD3 and 25OHD2 can be reliably quantified in archived 3.2 mm dried blood spots. We can not be certain that the levels we measure in archived samples are exactly the same as when they were collected. However, the fact that the DBS levels reflect the well-known seasonal variation in this vitamin and when corrected for sera, values fall within the normal range for 25OHD3, means that DBS are a useful tissue repository for testing a range of hypotheses linking developmental hypovitaminosis D and adverse health outcomes.

Prevalence of vitamin D deficiency and its relationship with thyroid autoimmunity in Asian Indians: a community-based survey

25-Hydroxy vitamin D (25(OH)D) deficiency is linked with predisposition to autoimmune type 1 diabetes and multiple sclerosis. Our objective was to assess the relationship between serum 25(OH)D levels and thyroid autoimmunity. Subjects included students, teachers and staff aged 16–60 years (total 642, 244 males, 398 females). Serum free thyroxine, thyroid-stimulating hormone (TSH), and thyroid peroxidase autoantibodies (TPOAb), intact parathyroid hormone and 25(OH)D were measured by electrochemiluminescence and RIA, respectively. Thyroid dysfunction was defined if (1) serum TSH ≥ 5 μU/ml and TPOAb>34 IU/ml or (2) TSH ≥ 10 μU/ml but normal TPOAb. The mean serum 25(OH)D of the study subjects was 17·5 (sd 10·2) nmol/l with 87 % having values ≤ 25 nmol/l. TPOAb positivity was observed in 21 % of subjects. The relationship between 25(OH)D and TPOAb was assessed with and without controlling for age and showed significant inverse correlation (r − 0·08, P = 0·04) when adjusted for age. The prevalence of TPOAb and thyroid dysfunction were comparable between subjects stratified according to serum 25(OH)D into two groups either at cut-off of ≤ 25 or >25 nmol/l or first and second tertiles. Serum 25(OH)D values show only weak inverse correlation with TPOAb titres. The presence of such weak association and narrow range of serum 25(OH)D did not allow us to interpret the present results in terms of quantitative cut-off values of serum 25(OH)D. Further studies in vitamin D-sufficient populations with wider range of serum 25(OH)D levels are required to substantiate the findings of the current study.

Association between serum 25(OH)D and death from prostate cancer

Based on observations that for certain cancers, mortality varies according to sun exposure, vitamin D has been proposed to influence on disease progression. This study aims to investigate whether serum levels of 25(OH)D are associated with prognosis in patients with prostate cancer. In total, 160 patients with a serum sample in the JANUS serum bank were included. For 123 patients a pre-treatment serum sample was taken, whereas 37 of the patients had received hormone therapy prior to the blood collection. The serum level of 25(OH)D was classified as low (<50 nmol l(-1)), medium (50-80 nmol l(-1)) or high (>80 nmol l(-1)). A Cox proportional hazard regression model was used to assess the association between serum 25(OH)D and cancer mortality. During follow-up, 61 deaths occurred, of whom 52 died of prostate cancer. The median time of follow-up was 44.0 months (range, 1.2-154.6). Serum 25(OH)D at medium or high levels were significantly related to better prognosis (RR 0.33; 95% CI 0.14-0.77, RR 0.16; 95% CI 0.05-0.43) compared with the low level. Analysis restricted to patients receiving hormone therapy gave a stronger association. The serum level of 25(OH)D may be involved in disease progression and is a potential marker of prognosis in patients with prostate cancer.

Osteoporosis in developing countries

Osteoporosis poses a huge challenge in developing countries due to demographic transition and aging of the population coupled with limited availability of resources. The exact disease burden is difficult to quantify because of the paucity of data. Ethnicity affects bone density as well as fracture risk. Population-specific normative data for bone density are lacking in large parts of the world. Vitamin D deficiency is common even in sunny countries. The WHO has developed an algorithm for estimation of 10-year fracture risk which may be used even in the absence of bone mineral density.

Clinical practice. Primary ovarian insufficiency

A 30-year-old woman presents with a history of no menses since she stopped taking oral contraceptives 6 months ago in order to conceive. She had undergone puberty that was normal in both timing and development, with menarche at 12 years of age. At 18 years of age, she started taking oral contraceptives for irregular menses. She reports stress at work. Her weight is 59 kg, and her height 1.66 m; her body-mass index (the weight in kilograms divided by the square of the height in meters) is 21.3. There is no galactorrhea, hirsutism, or acne. The pelvic examination is normal, a pregnancy test is negative, the prolactin level is normal, and the follicle-stimulating hormone (FSH) level is in the menopausal range. How should she be evaluated and treated?

Supplementation of the diet with the functional fiber PolyGlycoplex is well tolerated by healthy subjects in a clinical trial

Background

The relationship of dietary fiber to overall health is of great importance, as beneficial effects have been demonstrated with the use of fiber from diverse sources, some traditional, other novel. PolyGlycopleX^® (PGX^®) is a unique proprietary product composed of three water-soluble polysaccharides, that when processed using novel technology give rise to a final product – a soluble, highly viscous functional fiber.

Methods

Because of its potential use in food and dietary supplements, a randomized, double-blind, placebo controlled clinical study was conducted to evaluate the tolerance to PGX ingestion for 21 days, to a maximum dose level of 10 g per day, in healthy male and female volunteers. The main objective of the study was to evaluate the overall gastrointestinal (GI) tolerance, while secondary objectives were to evaluate possible changes in hematological, biochemical, urinary and fecal parameters.

Results

Results show that PGX is well tolerated as part of a regular diet with only mild to moderate adverse effects, similar to those seen with a moderate intake of dietary fiber in general, and fruits and vegetables. Because PGX is a highly viscous, functional fiber, it also demonstrates several physiological responses including, but not limited to maintaining healthy total and LDL cholesterol and uric acid levels.

Incident invasive breast cancer, geographic location of residence, and reported average time spent outside

There have been reports of greater breast cancer incidence and mortality at northern compared with southern latitudes postulated to be related to vitamin D exposure. Among 71,662 participants in the Women's Health Initiative Observational Study (WHIOS) free of cancer at baseline (1993-1998), associations were explored between incident invasive postmenopausal breast cancer (n = 2,535), over approximately 8.6 years follow-up, and the following: (a) region of residence at birth, age 15 years, age 35 years; (b) region of residence at WHIOS baseline; and (c) clinic center solar irradiance. Hazard ratios and 95% confidence intervals (CI) for breast cancer were estimated after adjustment for individual level confounders. There was no difference in breast cancer risk by region of earlier life, baseline residence, or solar irradiance measured in Langelys (gm-cal) per cm(2). There was an observed 15% decreased risk among women residing in areas of low versus high solar irradiance measured in Watts per m(2) (95% CI, 2-26%). However, the associated P(trend) of 0.20 was not significant. Conversely, women who reported spending on average <30 minutes versus >2 hours outside in daylight year round at WHIOS year 4 follow-up (n = 46,926), had a 20% (95% CI, 2-41%; P(trend) = 0.001) increased risk of breast cancer. In conclusion, region of residence and geographic solar irradiance are not consistently related to risk of breast cancer and may not be sufficient proxy measures for sunlight/vitamin D exposure. The observed association between time spent outside and breast cancer risk support the hypothesis that vitamin D may protect against breast cancer.

Genetic polymorphisms of the vitamin D binding protein and plasma concentrations of 25-hydroxyvitamin D in premenopausal women

BACKGROUND

Vitamin D status, determined on the basis of 25-hydroxyvitamin D [25(OH)D] concentrations, is associated with the risk of several diseases. Vitamin D binding protein (DBP) is the major carrier of vitamin D and its metabolites, but the role of DBP single nucleotide polymorphisms (SNPs) on 25(OH)D concentrations is unclear.

OBJECTIVE

The objective was to evaluate the association of 2 DBP gene SNPs with 25(OH)D concentrations and explore whether such association varies according to the amount of vitamin D that needs to be transported.

DESIGN

This cross-sectional study included 741 premenopausal white women, mostly of French descent. Plasma 25(OH)D concentrations were measured by radioimmunoassay. DBP-1 (rs7041) and DBP-2 (rs4588) were genotyped with a Sequenom MassArray platform. Associations and interactions were modeled by using multivariate linear regression.

RESULTS

DBP-1 and DBP-2 SNPs were in strong linkage disequilibrium and were both associated with 25(OH)D concentrations. An additional copy of the rare allele of DBP-1 or DBP-2 was associated with lower 25(OH)D concentrations (beta = -3.29, P for trend = 0.0003; beta = -4.22, P for trend < 0.0001, respectively). These DBP polymorphisms explained as much of the variation in circulating 25(OH)D as did total vitamin D intake (r2 = 1.3% for DBP-1, r2 = 2.0% for DBP-2, and r2 < or = 1.2% for vitamin D intake).

CONCLUSION

Circulating 25(OH)D concentrations in premenopausal women are strongly related to DBP polymorphisms. Whether DBP rare allele carriers have a different risk of vitamin D-related diseases and whether such carriers can benefit more or less from dietary interventions, vitamin D supplementation, or sun exposure need to be clarified.

Plasma 25-hydroxyvitamin d is associated with markers of the insulin resistant phenotype in nondiabetic adults

We examined the cross-sectional association between plasma 25-hydroxyvitamin D [25(OH)D] and markers of the insulin resistant phenotype. Plasma 25(OH)D concentrations were measured in 808 nondiabetic participants of the Framingham Offspring Study. Outcome measures included fasting and 2-h post 75-g oral glucose tolerance test (OGTT) glucose and insulin; these were used to calculate the homeostatic model assessment-insulin resistance (HOMA-IR) and insulin sensitivity index (ISI(0,120)). We also measured plasma adiponectin, triacylglycerol, and HDL cholesterol concentrations as markers of the insulin-resistant phenotype. After adjusting for age, sex, BMI, waist circumference, and current smoking status, plasma 25(OH)D concentration was inversely associated with fasting plasma glucose and insulin concentrations, and HOMA-IR. Compared with the participants in the lowest tertile category of plasma 25(OH)D, those in the highest tertile category had a 1.6% lower concentration of fasting plasma glucose (P-trend = 0.007), 9.8% lower concentration of fasting plasma insulin (P-trend = 0.001), and 12.7% lower HOMA-IR score (P-trend < 0.001). After adjusting for age and sex, plasma 25(OH)D was positively associated with ISI(0,120), plasma adiponectin, and HDL cholesterol and inversely associated with plasma triacylglycerol, but these associations were no longer significant after further adjustment for BMI, waist circumference, and current smoking status. 25(OH)D and 2-h post-OGTT glucose were not associated. Among adults without diabetes, vitamin D status was inversely associated with surrogate fasting measures of insulin resistance. These results suggest that vitamin D status may be an important determinant for type 2 diabetes mellitus.

Milk-Based Nutritional Supplements in Conjunction With Lifestyle Intervention in Overweight Adolescents

There are limited data on successful weight management approaches among adolescents from underserved communities. The primary aim of this study was to obtain preliminary data on the efficacy, safety, and acceptability of a lifestyle intervention with milk-based supplements among adolescents from underserved communities. The secondary aims of this study were to assess change in adiposity indices and metabolic indices and to measure compliance. The authors conducted a 12-week open-labeled lifestyle intervention. Adolescents were taught a structured meal plan, including the use of 2 milk-based supplements daily, and participated in weekly lifestyle counseling. Overweight was defined as a body mass index >85th percentile. Percent total body fat was estimated using bioelectric impedance. Fasting blood samples were used to measure insulin indices and other biochemical safety tests. The sample consisted of 40 adolescents (70% girls, 83% minority). Although there was no significant change in body mass index (median [Q1, Q3]; -0.10 [-0.91, 0.61] kg/m(2), P = .26), participants showed a decrease in body mass index z score (-0.03 [-0.08, 0.01] SD, P = .01]), weight z score (-0.04 [-0.11, 0.02] SD, P = .001), and percent total body fat (-1.20 [-2.55, -0.12]%, P = .0001). No new onset of type 2 diabetes mellitus was reported, and plasma vitamin D increased (P < .01). Consumption of milk-based drinks increased from a median of 4.5 to 13.5 servings per week, whereas sugary beverages decreased from 8.0 to 3.8 servings per week. A lifestyle intervention that includes milk-based supplements may safely improve some adiposity indices and decrease intake of sugary beverages among overweight adolescents from underserved areas.

Chemotherapy is linked to severe vitamin D deficiency in patients with colorectal cancer

BACKGROUND

Preclinical and clinical evidence support an association between vitamin D deficiency and an increased risk of colorectal cancer. Normal vitamin D status has been linked to favorable health outcomes ranging from decreased risk of osteoporosis to improved cancer mortality. We performed a retrospective study to assess the impact of metastatic disease and chemotherapy treatment on vitamin D status in patients with colorectal cancer residing in Western New York.

MATERIALS AND METHODS

Patients, 315, with colorectal cancer treated in a single institute were assayed for 25-OH vitamin D. The association of age, gender, primary disease site and stage, body mass index, and chemotherapy with vitamin D status was investigated.

RESULTS

Vitamin D deficiency was common among participants with a median 25-OH vitamin D level of 21.3 ng/ml (optimal range 32-100 ng/ml). Primary site of disease and chemotherapy status were associated with very low 25-OH vitamin D levels (< or =15 ng/ml) on multivariate analysis. Patients receiving chemotherapy and patients with a rectal primary were 3.7 and 2.6-fold more likely to have severe vitamin D deficiency on multivariate analysis than nonchemotherapy patients and colon cancer primary patients, respectively.

CONCLUSIONS

Chemotherapy is associated with a significant increase in the risk of severe vitamin D deficiency. Patients with colorectal cancer, especially those receiving chemotherapy, should be considered for aggressive vitamin D replacement strategies.

The association between ketoacidosis and 25(OH)-vitamin D levels at presentation in children with type 1 diabetes mellitus

BACKGROUND

There is considerable evidence supporting the role of vitamin D deficiency in the pathogenesis of type 1 diabetes mellitus (T1DM). Vitamin D deficiency is also associated with impairment of insulin synthesis and secretion. There have been no formal studies looking at the relationship between 25(OH)-vitamin D(3) and the severity of diabetic ketoacidosis (DKA) in children at presentation with T1DM.

OBJECTIVE

To determine the relationship between measured 25(OH)-vitamin D(3) levels and the degree of acidosis in children at diagnosis with T1DM.

SUBJECTS

Children presenting with new-onset T1DM at a tertiary children's hospital.

METHODS

25(OH)-vitamin D(3) and bicarbonate levels were measured in children at presentation with newly diagnosed T1DM. Those with suboptimal 25(OH)-vitamin D(3) levels (<50 nmol/L) had repeat measurements performed without interim vitamin D supplementation.

RESULTS

Fourteen of the 64 children had low 25(OH)-vitamin D(3) levels at presentation, and 12 of these had low bicarbonate levels (<18 mmol/L) (p = 0.001). Bicarbonate explained 20% of the variation in vitamin D level at presentation (partial r(2) = 0.20, p < 0.001) and ethnic background a further 10% (partial r(2) = 0.10, p = 0.002). The levels of 25(OH)-vitamin D(3) increased in 10 of the 11 children with resolution of the acidosis.

CONCLUSIONS

Acid-base status should be considered when interpreting 25(OH)-vitamin D(3) levels in patients with recently diagnosed T1DM. Acidosis may alter vitamin D metabolism, or alternatively, low vitamin D may contribute to a child's risk of presenting with DKA.

Vitamin D and diabetes mellitus

Better understanding of the physiological role of the vitamin-D system, in particular its potential effects on inflammatory and autoimmune conditions as well as on insulin secretion and possibly also on insulin resistance, increased the interest in its potential role in prevention and control of the diabetic condition, both type-1 and -2 diabetes. Both these conditions are associated with inflammation and type-1 diabetes also with an autoimmune pathology. Indeed, animal and human studies support the notion that adequate vitamin-D supplementation may decrease the incidence of type-1 and possibly also of type-2 diabetes mellitus and may improve the metabolic control in the diabetes state. However, the exact mechanisms by which vitamin-D and calcium supplementation exert their beneficial effects are not clear and need further investigation.

Type 1 diabetes, the A1 milk hypothesis and vitamin D deficiency

The 'A1' genetic variant of beta-casein in milk has been linked to type 1 diabetes (T1D). The keystone piece of supporting evidence is an ecological study positively correlating the incidence of T1D with amount of A1 beta-casein consumption per capita. Of relevance, A1 beta-casein consumption is also positively correlated with latitude, itself implicated in T1D through vitamin D deficiency. Ecological and biological evidence convincingly implicate vitamin D deficiency in T1D. Latitude is a confounder of the ecological data that underpin the hypothesis that A1 beta-casein in cow's milk is a causative factor in T1D.

The effect of combined calcium and vitamin D3 supplementation on serum intact parathyroid hormone in moderate CKD

BACKGROUND

Studies addressing the effects of vitamin D(3) supplementation on secondary hyperparathyroidism in patients with moderate chronic kidney disease are scarce.

STUDY DESIGN

Post hoc analysis of the randomized clinical trial Vitamin D, Calcium, Lyon Study II (DECALYOS II) to assess effects according to baseline estimated glomerular filtration rate (eGFR).

SETTING & PARTICIPANTS

Multicenter, randomized, double-blinded, placebo-controlled study of 639 elderly women randomly assigned to calcium-vitamin D(3) fixed combination; calcium plus vitamin D(3) separate combination, or placebo.

INTERVENTIONS

Placebo or calcium (1,200 mg) and vitamin D(3) (800 IU) in fixed or separate combination.

OUTCOMES & MEASUREMENTS

Proportion of participants with a mean decrease in intact parathyroid hormone (iPTH) level of 30% or greater. eGFR was calculated using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation and categorized as 60 or greater, 45 to 59, and less than 45 mL/min/1.73 m(2).

RESULTS

610 participants had an eGFR at baseline: 288 (47.2%), 222 (36.4%), and 100 (16.4%) were in each decreasing eGFR category. Across decreasing eGFR groups, 88%, 86%, and 89% had 25-hydroxyvitamin D (25[OH]D) levels less than 15 ng/mL at baseline. On treatment, similar improvements in the proportion of participants achieving 25(OH)D levels greater than 30 ng/mL at 6 months were seen in all kidney function groups (43%, 49%, and 41%, respectively). Active regimens versus placebo increased mean 25(OH)D levels from baseline in all eGFR groups at all times (P < 0.001 for all). The proportion with a 30% or greater decrease in iPTH level at 6 months was 50% in all eGFR groups on treatment versus 6% to 9% for placebo (P < 0.001 for all). The effects of the intervention on iPTH levels did not differ according to baseline eGFR (interaction P > 0.1 for all times).

LIMITATIONS

This study included only elderly white women.

CONCLUSION

Vitamin D(3) was effective in increasing 25(OH)D and decreasing iPTH levels in patients with moderate chronic kidney disease.

Vitamin D beyond bones in chronic obstructive pulmonary disease: time to act

The discovery that the vitamin D endocrine system regulates a very large number of genes and their associated biological processes improves our insight into the fundamental role of vitamin D and sun exposure for human health. Accumulating epidemiological data are linking a low vitamin D nutritional status to highly prevalent diseases such as cancer, autoimmune diseases, and chronic infections. Approximately half of the world's elderly, and to a lesser extent the adult population, have insufficient to deficient 25-hydroxyvitamin D (25-OHD) serum levels, and several intervention studies are being undertaken to study the impact of adequate vitamin D supplementation in chronic diseases. In this perspective we claim that chronic obstructive pulmonary disease (COPD) is a candidate disease for which vitamin D supplementation might be beneficial. Epidemiological studies revealed a dose-dependent association between serum 25-OHD levels and pulmonary function so that adequate vitamin D supplementation may extend beyond its protection against osteoporotic fractures. In line with the novel insights on its immune function, it is tempting to speculate that vitamin D may down-regulate the inflammatory immune response in the airways while boosting innate immune defense against different microorganisms. Apart from its affects on osteoporosis, vitamin D may also interfere with other comorbidities of COPD such as skeletal muscle weakness, cardiovascular disease, and cancer. Because respiratory treatments in COPD fail to reverse disease progression, interventional trials that may exploit the broader potential of vitamin D are warranted. A further challenge of such studies is to define optimal serum 25-OHD levels for such noncalcemic endpoints.

Expanding targets of vitamin D receptor activation: downregulation of several RAS components in the kidney

Vitamin D receptor (VDR) activation has a beneficial influence on the progression of experimental renal insufficiency, and reduced renal tissue renin expression may play a role in this process. Freundlich and co-workers now report that VDR activation also suppresses the expression of angiotensinogen, angiotensin II type 1 receptor, and renin receptor in the kidneys of 5/6 nephrectomized rats, effects associated with reduced blood pressure and urinary protein excretion and with alleviated renal tissue damage.

Autoimmune hepatitis in a North American Aboriginal/First Nations population

North American Aboriginal populations are at increased risk for developing immune-mediated disorders, including autoimmune hepatitis. In the present study, the demographic, clinical, biochemical, serological, radiological and histological features of autoimmune hepatitis were compared in 33 First Nations (FN) and 150 predominantly Caucasian, non-FN patients referred to an urban tertiary care centre. FN patients were more often female (91% versus 71%; P=0.04), and more likely to have low serum albumin (69% versus 36%; P=0.0006) and elevated bilirubin (57% versus 35%; P=0.01) levels on presentation compared with non-FN patients. They also had lower hemoglobin, and complement levels, more cholestasis and higher serum immunoglobulin A levels than non-FN patients (P=0.05 respectively). Higher histological grades of inflammation and stages of fibrosis, and more clinical and radiological evidence of advanced liver disease were observed in FN patients, but the differences failed to reach statistical significance. The results of the present study suggest that in addition to being more common, autoimmune hepatitis may be more severe in FN populations, compared with predominantly Caucasian, non-FN populations.

Vitamin D deficiency an important, common, and easily treatable cardiovascular risk factor?

Vitamin D deficiency is a highly prevalent condition, present in approximately 30% to 50% of the general population. A growing body of data suggests that low 25-hydroxyvitamin D levels may adversely affect cardiovascular health. Vitamin D deficiency activates the renin-angiotensin-aldosterone system and can predispose to hypertension and left ventricular hypertrophy. Additionally, vitamin D deficiency causes an increase in parathyroid hormone, which increases insulin resistance and is associated with diabetes, hypertension, inflammation, and increased cardiovascular risk. Epidemiologic studies have associated low 25-hydroxyvitamin D levels with coronary risk factors and adverse cardiovascular outcomes. Vitamin D supplementation is simple, safe, and inexpensive. Large randomized controlled trials are needed to firmly establish the relevance of vitamin D status to cardiovascular health. In the meanwhile, monitoring serum 25-hydroxyvitamin D levels and correction of vitamin D deficiency is indicated for optimization of musculoskeletal and general health.

Seasonality of birth in children with central nervous system tumours in Denmark, 1970-2003

We investigated possible seasonal variation of births among children <20 years with a central nervous system tumour in Denmark (N=1640), comparing them with 2,582,714 children born between 1970 and 2003. No such variation was seen overall, but ependymoma showed seasonal variation.

Vitamin D and mood disorders among women: an integrative review

This integrative review evaluates research studies that investigated the association between vitamin D and mood disorders affecting women to determine whether further research comparing these variables is warranted. A literature search using CINAHL, PsycINFO, MEDLINE, and PubMed databases was conducted to locate peer-reviewed mood disorder research studies that measured serum 25-hydroxyvitamin D (25[OH]D) levels. Four of six studies reviewed imparted significant results, with all four showing an association between low 25(OH)D levels and higher incidences of four mood disorders: premenstrual syndrome, seasonal affective disorder, non-specified mood disorder, and major depressive disorder. This review indicates a possible biochemical mechanism occurring between vitamin D and mood disorders affecting women, warranting further studies of these variables using rigorous methodologies.

Sunlight, UV-radiation, vitamin D and skin cancer: how much sunlight do we need?

Vtamin D is the sunshine vitamin for good reason. During exposure to sunlight, the utraviolet B photons enter the skin and photolyze 7-dehydrocholesterol to previtamin D3 which in turn is isomerized by the body's temperature to vitamin D3. Most humans have depended on sun for their vitamin D requirement. Skin pigment, sunscreen use, aging, time of day, season and latitude dramatically affect previtamin D3 synthesis. Vitamin D deficiency was thought to have been conquered, but it is now recognized that more than 50% of the world's population is at risk for vitamin D deficiency. This deficiency is in part due to the inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D. Vitamin D deficiency causes growth retardation and rickets in children and will precipitate and exacerbate osteopenia, osteoporosis and increase risk of fracture in adults. The vitamin D deficiency has been associated pandemic with other serious consequences including increased risk of common cancers, autoimmune diseases, infectious diseases and cardiovascular disease. There needs to be a renewed appreciation of the beneficial effect of moderate sunlight for providing all humans with their vitamin D requirement for health.

Vitamin D status of clinical practice populations at higher latitudes: analysis and applications

BACKGROUND

Inadequate levels of vitamin D (VTD) throughout the life cycle from the fetal stage to adulthood have been correlated with elevated risk for assorted health afflictions. The purpose of this study was to ascertain VTD status and associated determinants in three clinical practice populations living in Edmonton, Alberta, Canada--a locale with latitude of 53 degrees 30'N, where sun exposure from October through March is often inadequate to generate sufficient vitamin D.

METHODS

To determine VTD status, 1,433 patients from three independent medical offices in Edmonton had levels drawn for 25(OH)D as part of their medical assessment between Jun 2001 and Mar 2007. The relationship between demographic data and lifestyle parameters with VTD status was explored. 25(OH)D levels were categorized as follows: (1) Deficient: <40 nmol/L; (2) Insufficient (moderate to mild): 40 to <80 nmol/L; and (3) Adequate: 80-250 nmol/L. Any cases <25 nmol/L were subcategorized as severely deficient for purposes of further analysis.

RESULTS

240 (16.75% of the total sample) of 1,433 patients were found to be VTD 'deficient' of which 48 (3.35% of the overall sample) had levels consistent with severe deficiency. 738 (51.5% of the overall sample) had 'insufficiency' (moderate to mild) while only 31.75% had 'adequate' 25(OH)D levels. The overall mean for 25(OH) D was 68.3 with SD=28.95. VTD status was significantly linked with demographic and lifestyle parameters including skin tone, fish consumption, milk intake, sun exposure, tanning bed use and nutritional supplementation.

CONCLUSION

A high prevalence of hypovitaminosis-D was found in three clinical practice populations living in Edmonton. In view of the potential health sequelae associated with widespread VTD inadequacy, strategies to facilitate translation of emerging epidemiological information into clinical intervention need to be considered in order to address this public health issue. A suggested VTD supplemental intake level is presented for consideration.

Hungry bone syndrome after parathyroidectomy caused by an ectopic parathyroid adenoma

Hungry bone syndrome (HBS), i.e., persistent hypocalcemia and hypophosphatemia as a result of extensive remineralization, is rarely encountered in children after parathyroid surgery. Herein, we report a 12-year-old girl who was diagnosed to have an ectopic parathyroid adenoma, and HBS was observed in the postsurgical follow-up. The diagnosis and the risk factors are discussed in the light of the literature.

Nonclassic actions of vitamin D

CONTEXT

Vitamin D receptors are found in most tissues, not just those participating in the classic actions of vitamin D such as bone, gut, and kidney. These nonclassic tissues are therefore potential targets for the active metabolite of vitamin D, 1,25(OH)(2)D. Furthermore, many of these tissues also contain the enzyme CYP27B1 capable of producing 1,25(OH)(2)D from the circulating form of vitamin D. This review was intended to highlight the actions of 1,25(OH)(2)D in several of these tissues but starts with a review of vitamin D production, metabolism, and molecular mechanism.

EVIDENCE ACQUISITION

Medline was searched for articles describing actions of 1,25(OH)(2)D on parathyroid hormone and insulin secretion, immune responses, keratinocytes, and cancer.

EVIDENCE SYNTHESIS

Vitamin D production in the skin provides an efficient source of vitamin D. Subsequent metabolism to 1,25(OH)(2)D within nonrenal tissues differs from that in the kidney. Although vitamin D receptor mediates the actions of 1,25(OH)(2)D, regulation of transcriptional activity is cell specific. 1,25(OH)(2)D inhibits PTH secretion but promotes insulin secretion, inhibits adaptive immunity but promotes innate immunity, and inhibits cell proliferation but stimulates their differentiation.

CONCLUSIONS

The nonclassic actions of vitamin D are cell specific and provide a number of potential new clinical applications for 1,25(OH)(2)D(3) and its analogs. However, the use of vitamin D metabolites and analogs for these applications remains limited by the classic actions of vitamin D leading to hypercalcemia and hypercalcuria.

Effect of vitamin D supplementation on bone health parameters of healthy young Indian women

SUMMARY: There is a huge prevalence of hypovitaminosis D in the Indian population. We studied the efficacy and safety of oral vitamin D supplementation in apparently healthy adult women. Monthly cholecalciferol given orally, 60,000 IU/month during summers and 120,000 IU/month during winters, safely increases 25-hydroxyvitamin D (25(OH)D) levels to near normal levels. INTRODUCTION: There is a huge burden of hypovitaminosis D in the Indian population. The current recommendation for vitamin D supplementation is not supported by sufficient evidence. METHODS: Study subjects included 100 healthy adult women of reproductive age group from hospital staff. They were randomized into group A (control) and group B (supplement) by simple randomization. Group B received 60,000 IU of cholecalciferol/month administered orally for 3 months, and then group A received 60,000 IU and group B 120,000 IU/month for 6 months. RESULTS: Mean baseline 25(OH)D level was 4.5 +/- 3.1 ng/ml and parathyroid hormone level was 50 +/- 25 pg/ml. In group B, 25(OH)D levels increased from 4.8 +/- 3.5 to 31.6 +/- 15.5 ng/ml (P < 0.001) in 3 months. Interestingly, the increase, although of lower magnitude, was also observed in control group A, from 4.5 +/- 3.4 ng/ml (in spring) to 10.8 +/- 7.2 ng/ml (in summer; P < 0.001). In group A (60,000 IU/month), mean 25(OH)D level had increased to 22.3 +/- 12.4 ng/ml (P < 0.001) at 9 months (winter). In group B (120,000 IU/month), 25(OH)D levels were maintained at 30.7 +/- 12.8 ng/ml at 9 months (winter). CONCLUSION: Our data show that monthly administration of 60,000 IU cholecalciferol in healthy subjects with hypovitaminosis D may suffice in summer months, but higher doses may be more appropriate during winter months.

Contributions of 25-hydroxyvitamin D, co-morbidities and bone mass to mortality in Japanese postmenopausal women

It was reported that low bone mineral density (BMD), osteoporotic fractures and low serum 25-hydroxyvitamin D (25-OHVD) levels increase the risk of mortality in elderly Caucasian people. However, there is no data available on the relationship between bone mineral density or 25-OHVD levels and mortality in elderly Asian women. To determine whether or not low bone mineral density (BMD) or low 25-OHVD levels contribute to increased mortality risk, we conducted a prospective observational study in 1232 ambulatory postmenopausal female volunteers. Information was obtained from the subjects on baseline BMD, the serum levels of biochemical indices including 25-OHVD, prevalent fractures, co-morbidities and lifestyle variables. The participants were observed for a total of 6.9+/-3.6 years (mean+/-SD) and a total of 107 participants (8.7%) were dead during the observation. Mortality was assessed and confirmed on the certificates or hospital records or information from their family. In addition to traditional risks for mortality, such as age (Hazard ratio, 1.73, 95% CI, 1.51-1.98, P<0.01), 25-OHVD level <50 nmol/l (HR 2.17, 1.27-3.72, P=0.01), prevalent malignancies (HR 5.60, 3.36-9.31, P<0.01) and existing osteoporosis (HR 2.14, 1.22-3.75, P=0.01) were found to be significant independent risk factors for all-cause mortality by using multivariate Cox's regression analysis. It is suggested that prevalent osteoporosis, prevalent malignancy or lower levels of 25-OHVD represent powerful risk factors for mortality.

Vitamin D: current status and perspectives

The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25-OH vitamin D into its most active metabolite, 1,25-(OH)

Clin Chem Lab Med 2009;47:120–7.