Vitamin D deficiency

Solar ultraviolet-B irradiance and vitamin D may reduce the risk of septicemia

The primary features of the epidemiology of septicemia in the United States include highest rates in winter and the Northeast, lowest in fall and in the West; higher rates among African Americans than white Americans; a rapid increase in incidence with age; comorbidity with several chronic and infectious diseases; and a rapid increase in incidence rate starting in the early 1980s. This article reviews the literature on the epidemiology of septicemia in the United States, along with the roles of solar ultraviolet-B (UVB) and vitamin D3 related to the more important features. Solar UVB doses in summer are highest in the Southwest and lowest in the Northeast. Serum 25-hydroxyvitamin D [25(OH)D] levels are highest in summer, lowest in winter. African Americans have much lower 25(OH)D levels than those of white Americans. Serum 25(OH)D levels decline rapidly with advancing age. The risk of diseases comorbid with septicemia are generally inversely correlated with serum 25(OH)D levels. Sun-avoidance messages may have led to lower population levels of 25(OH)D, although prevalence of antibiotic-resistant bacteria may have increased. Previous reports have shown that 1,25-dihydroxyvitamin D upregulates human cathelicidin, LL-37, which has antimicrobial as well as antiendotoxin activity. The general agreement between the epidemiology of septicemia in the United States and the variations of solar UVB and the effects of vitamin D supports the hypothesis that both play important roles in reducing the risk of septicemia. Further study is warranted to evaluate this hypothesis.

Effect of bimonthly supplementation with oral cholecalciferol on serum 25-hydroxyvitamin D concentrations in HIV-infected children and adolescents

OBJECTIVE

Vitamin D insufficiency occurs commonly in HIV-infected youth in the United States. In light of the importance of vitamin D for skeletal and nonskeletal health, including innate immunity, developing methods for improving vitamin D status in HIV-infected children and adolescents is an important area of clinical research. The objective of this study was to evaluate the effect of administration of oral cholecalciferol, 100,000 IU every 2 months, and 1 g/day calcium on serum 25-hydroxyvitamin D concentrations, serum and urine calcium, and HIV disease progression during a 12-month period.

METHODS

HIV-infected children and adolescents who were aged 6 to 16 years were randomly assigned to receive vitamin D (100,000 IU bimonthly) and calcium (1 g/day; n = 29) or double placebo (n = 27). Serum 25-hydroxyvitamin D concentrations as measured by radioimmunoassay, albumin-corrected calcium concentrations, and spot urinary calcium-creatinine ratios were determined monthly.

RESULTS

No abnormalities in serum calcium concentration were observed. One participant who received placebo developed hypercalciuria. No group differences were seen in the change in CD4 count or CD4% or viral load during 12 months. The overall mean monthly serum 25-hydroxyvitamin D concentrations were higher in the group that received vitamin D and calcium than in the placebo group, as was the monthly serum 25-hydroxyvitamin D area under the curve. After completing 12 months of study, 2 (6.7%) participants in the group that received vitamin D and calcium had a trough serum 25-hydroxyvitamin D concentration <20 ng/mL compared with 14 (50%) in the placebo group. Twelve (44.4%) in the group that received vitamin D and calcium had a trough serum 25-hydroxyvitamin D concentration of > or =30 ng/mL compared with 3 (11.1%) in the placebo group.

CONCLUSIONS

Administration of oral cholecalciferol to HIV-infected children and adolescents at a dosage of 100,000 IU every 2 months, together with 1 g/day calcium, is safe and results in significant increases in serum 25-hydroxyvitamin D concentrations.

Effect of vitamin D supplementation in the institutionalized elderly

An intervention study with vitamin D supplementation was conducted in order to study the amount of vitamin D required in the elderly. Sixty-four institutionalized elderly were randomly assigned to two groups: group (A) to take a beverage containing 200 mg calcium daily, and group (B) to take a beverage containing 200 mg calcium and 5 microg vitamin D daily for 30 days. Prior to the study, the subjects' average vitamin D intake was 7.3 microg/day, which is approximately 150% of the current adequate intake (AI), however their mean plasma 25 OH-D level at baseline was only 12 ng/mL, strongly indicating hypovitaminosis D. During the study, average plasma 25 OH-D concentration significantly increased to 14.7 ng/mL in group (B), but not in group (A). However, group (B) was still in the hypovitaminosis range. Thus, daily intake exceeding the current AI of 5 microg is required for the institutionalized elderly.

Severe hypophosphatemic osteomalacia with Fanconi syndrome, renal tubular acidosis, vitamin D deficiency and primary biliary cirrhosis

A 49-year-old woman was admitted to our hospital for back pain with marked thoracic and extremity deformities leading to bed-rest for three years. She was diagnosed with hypophosphatemic osteomalacia based on her symptoms, X-ray and bone scintigram, high serum alkaline phosphatase level, and low serum levels of both phosphorus and 1,25 dihydroxyvitamin D(3) with inhibition of phosphorus reabsorption. Fanconi syndrome with renal tubular acidosis, vitamin D deficiency and primary biliary cirrhosis were related to the pathogenesis of osteomalacia in this case. Several causal diseases may be concomitantly responsible for acceleration of the severity of osteomalacia in this patient.

Gender- and compartment-specific bone loss in C57BL/6J mice: correlation to season?

Seasonal variation in bone mineral density (BMD) has been documented in humans, and has been attributed to changes in 25-hydroxyvitamin D [25(OH)D] synthesis. To test the hypothesis that seasonal changes in bone mass occur in laboratory mice, we measured body composition, femoral bone phenotypes, and serum bone markers in 16-wk-old male and female C57BL/6 (B6) mice during the summer (June-August) and winter (December-February) months at The Jackson Laboratory in Bar Harbor, Maine. Both male and female B6 mice had higher volumetric BMD in the summer than winter. Females showed reduced trabecular bone, whereas males showed changes in bone volume. Males, but not females, had higher insulin-like growth factor 1 in summer than in winter, and only males showed an increase in body weight during the winter. No seasonal differences in serum TRAP5b, osteocalcin, or 25(OH)D were noted for either sex. We conclude that seasonal variation in skeletal and body composition parameters in B6 mice is significant and must be considered when performing longitudinal phenotyping of the skeleton. Further studies are needed to determine the environmental factors that cue seasonal changes in body composition and the mechanisms that produce these changes.

A critical review of Vitamin D and Cancer: A report of the IARC Working Group

The International Agency for Research on Cancer (IARC) released a report, Vitamin D and Cancer, on November 25, 2008. The report focused on the current state of knowledge and level of evidence of a causal association between vitamin D status and cancer risk. Although presenting and evaluating evidence for the beneficial role of UVB and vitamin D in reducing the risk of cancer, it discounted or omitted important evidence in support of the efficacy of vitamin D. The report largely dismissed or ignored ecological studies on the grounds that confounding factors might have affected the findings. The report accepted a preventive role of vitamin D in colorectal cancer but not for breast cancer.The only randomized controlled trial (RCT) on cancer incidence that used a sufficiently high dose of vitamin D (1,100 IU/day) and calcium (1,400-1,500 mg/day) found a 77% reduction in the risk of all-cancer incidence in postmenopausal women who received both, of which approximately 35% reduction in risk was attributed to vitamin D alone. Unfairly, the report dismissed these findings on the basis of a flawed critique.The report called for RCTs of vitamin D supplementation to settle the issue. Although RCTs theoretically would be beneficial, development of sound and effective public health policies does not necessarily depend on them, and the field of vitamin D, calcium and chronic disease has reached the point where RCTs may not be ethical.The IARC report should therefore not form the basis for public health policy decisions.

Standard multivitamin supplementation does not improve vitamin D insufficiency after burns

Children suffering severe burns develop progressive vitamin D deficiency because of inability of burned skin to produce normal quantities of vitamin D(3) and lack of vitamin D supplementation on discharge. Our study was designed to determine whether a daily supplement of a standard multivitamin tablet containing vitamin D(2) 400 IU (10 microg) for 6 months would raise serum levels of 25-hydroxyvitamin D [25(OH)D] to normal. We recruited eight burned children, ages 5-18, whose families were deemed reliable by the research staff. These children were given a daily multivitamin tablet in the hospital for 3 months in the presence of a member of the research staff and then given the remainder at home. At 6 months, the subjects returned for measurements of serum levels of 25(OH)D,1,25-dihydroxyvitamin D [1,25(OH)(2)D], intact parathyroid hormone (iPTH), Ca, P, albumin, and total protein as well as bone mass by dual energy X-ray absorptiometry. Serum 25(OH)D levels were compared to a group of seven age-matched burned children studied at an earlier date without the vitamin supplement but with the same method of determination of 25(OH)D at 6 months post-burn. In addition, the chewable vitamins were analyzed for vitamin D(2) content by high performance liquid chromatography. Serum concentration of 25(OH)D was 21 +/- 11(SD) ng/ml (sufficient range 30-100) with only one of the eight children having a value in the sufficient range. In comparison, the unsupplemented burn patients had mean serum 25(OH)D level of 16 +/- 7, P = 0.33 versus supplemented. Serum levels of 1,25(OH)(2)D, iPTH, Ca, P, albumin, and total protein were all normal in the supplemented group. Vitamin D(2) content of the chewable tablets after being saponified and extracted was 460 +/- 20 IU. Bone mineral content of the total body and lumbar spine, as well as lumbar spine bone density, failed to increase as expected in the supplemented group. No correlations were found between serum 25(OH)D levels and age, length of stay, percent body surface area burn or third-degree burn. Supplementation of burned children with a standard multivitamin tablet stated to contain 400 IU of vitamin D(2) failed to correct the vitamin D insufficiency.

A liquid chromatography/tandem mass spectrometry method for determination of 25-hydroxy vitamin D2 and 25-hydroxy vitamin D3 in dried blood spots: a potential adjunct to diabetes and cardiometabolic risk screening

BACKGROUND

Now emerging as an important risk factor for type 1 diabetes, vitamin D deficiency is also associated with obesity, metabolic syndrome, and type 2 diabetes and has been identified as a potential cardiometabolic risk factor. A simple, accurate screening test for 25-hydroxy vitamin D [25(OH)D] deficiency is needed. We developed a liquid chromatography/tandem mass spectrometry assay for 25-hydroxy vitamin D(2) [25(OH)D(2)] and 25-hydroxy vitamin D(3) [25(OH)D(3)] in dried blood spots.

METHOD

Blood spots were collected by finger stick simultaneously with serum samples obtained by venipuncture from healthy volunteers. Disks punched from the dried blood spots were sonicated with an internal standard solution of deuterated 25(OH)D(3) (26,26,26,27,27,27-d(6)). Methanol was added to precipitate proteins prior to extraction with hexane. The extracted samples were dried and reconstituted in 50:50 methanol:H(2)O before injection into a Varian 320-MS TQ mass spectrometer.

RESULTS

BLOOD SPOT ASSAY PRECISION WAS GOOD OVER THE REPORTABLE RANGE: interassay coefficients of variation were 13, 13, and 11% at concentrations of 14, 26, and 81 ng/ml, respectively, for 25-hydroxy vitamin D(3) and 12% at 23 ng/ml for 25(OH)D(2). The 25(OH)D(3) assay was linear from 3.5 to 75 ng/ml (R > 0.99). Blood spot and serum values showed excellent correlation for 25(OH)D(2) (R=0.90, n=54) and 25(OH)D(3) (R=0.91, n=83).

CONCLUSIONS

This blood spot assay for 25(OH)D(2) and 25(OH)D(3) provides a convenient and cost-effective alternative to serum assays and can be automated. This may be valuable in large-scale screening for risk of type 1 diabetes, for cardiometabolic risk screening, and for monitoring vitamin D supplementation.

Vitamin D status of Year 3 children and supplementation through schools with fortified milk

OBJECTIVE

To evaluate levels of vitamin D3 and HDL-cholesterol (HDL-C), and the ratio of HDL-C to LDL-cholesterol (LDL-C), in schoolchildren receiving vitamin-D-fortified, fat-depleted, high-Ca milk in schools.

DESIGN

Cross-sectional study of previously randomised schools receiving supplemental milk, compared with a matched control group.

SETTING

Low-decile Year 1-6 schools in the Waikato region of New Zealand.

SUBJECTS

Year 3 children from either milk schools or control schools, consenting to blood sampling.

RESULTS

For eighty-nine children receiving supplementary daily milk, vitamin D3 levels were significantly higher than in eighty-three control children matched for age, sex, body composition and ethnicity (mean (sd): 49.6 (15.8) v. 43.8 (14.7) nmol/l, P = 0.011), as were HDL-C levels (mean (sd): 1.47 (0.35) v. 1.35 (0.29) mmol/l, P = 0.024) and HDL-C:LDL-C (median: 0.79 v. 0.71, P = 0.026). LDL-C levels were similar in both groups (mean (sd): 2.07 (0.55) v. 2.16 (0.60) mmol/l, P = 0.31). Of control children, 32/83 (20.2 %) of the milk group (Pearson's chi2 = 7.00, P = 0.008). Mean 25-hydroxyvitamin D (vitamin D3) levels in the milk group were still below the lower end of the recommended normal range (60 nmol/l).

CONCLUSIONS

Vitamin D3 levels are low in low-decile Year 3 children in midwinter. Levels are improved with vitamin-D-fortified milk but still below the recommended range. HDL-C and HDL-C:LDL-C levels are improved in the milk-supplemented group. This supports the supply of vitamin-D-fortified, fat-reduced milk to schools.

On the relationship between erythemal and vitamin D action spectrum weighted ultraviolet radiation

Erythemally weighted solar ultraviolet (UV) radiation is often used to characterize the production of vitamin D in a human body. However, the vitamin D production action spectrum is different than that for erythemal UV. The vitamin D action spectrum weighted UV is more sensitive to UV-B, while the erythemal UV action spectrum has higher weighting coefficients than the vitamin D action spectrum in the UV-A part of the spectrum. Therefore, by using the erythemal UV as an estimate for the vitamin D action spectrum weighted UV can give results that differ by up to a factor of 5. This study examines the relationship between erythemal and vitamin D action spectrum weighted UV radiation using measurements of spectral UV at the surface by Brewer spectrophotometers that are part of the US and Canadian observational networks. It is shown that the ratio of vitamin D action spectrum weighted UV to erythemal UV is nearly constant for high levels of UV (UV Index greater than 5.5) and therefore vitamin D action spectrum weighted UV can be described in terms of erythemal UV. For lower levels of UV though this relationship should not be used. A simple formula that calculates vitamin D action spectrum weighted UV from UV Index is developed. An empirical formula that expresses the ratio of vitamin D action spectrum weighted UV to erythemal UV as a function of the solar zenith angle and column ozone is also suggested. The geographical distributions of vitamin D action spectrum weighted UV in the US and Canada are discussed.

[Gastrointestinal diseases and osteomalacia]

Osteomalacia is a metabolic bone disease associated with impaired mineralization of the bone due to Vitamin D and Calcium deficiency that can develop in gastrointestinal disorders. Gastrointestinal malabsorption after surgery, in disorders of the small bowl, in diseases of the hepatobiliary tree and in pancreatic insufficiency can lead to decreased enteral resorption of the fat-soluble Vitamin D and/or depletion of endogenous Vitamin D stores due to abnormal enterohepatic circulation. As a consequence of the Vitamin D deficiency in combination with the underlying condition patients develop an impaired calcium absorption resulting in hypocalcaemia, which leads to defective bone mineralization. Additionally chronic gastrointestinal inflammation and corticosteroid therapy - which is often needed in these patients - have a negative effect on bone metabolism as well. The therapy consists of oral substitution of Vitamin D and Calcium as well as sufficient sun light exposure or in severe cases the use of artificial UVB-radiation.

[Daily clinical practice: Biological testing in osteoporosis]

Although biological testing has nothing to do with the diagnosis of osteoporosis, it can help the physician to: 1) identify secondary causes of low bone mass and/or fracture. There is however currently no consensus to define the biochemical parameters to be measured in this case. The cost-effectiveness of the biological evaluation, that is, measuring a minimum of parameters to detect a maximum of anomalies needs to be considered. Most experts agree that malignancy and especially a myeloma should be ruled out, and that an evaluation of calcium/phosphorus metabolism including the measurement of serum calcium, phosphate, PTH and 25 hydroxy-vitamin D should be performed. This allows to detect many anomalies including two very frequent conditions, primary hyperparathyroidism and vitamin D deficiency. Note however that complementary testing is generally needed to identify other diseases; 2) evaluate efficacy and observance of some osteoporosis treatments especially oral bisphosphonates. In this case, the evolution of the blood or urine level of some markers of bone turnover over a 3-6 month period after the initiation of therapy will be considered. For example, a decrease of more than 30% in the serum concentration of CTX (C-terminal telopeptide of type I collagen) will be regarded as a significant change indicating that treatment has reduced bone resorption.

Preoperative vitamin D replacement therapy in primary hyperparathyroidism: safe and beneficial?

BACKGROUND

The significance of vitamin D deficiency with primary hyperparathyroidism (PHPT) remains unclear. The safety and value of preoperative vitamin D (Vit D) replacement is unknown.

METHODS

A prospective surgical database of PHPT patients was queried to identify those who were vitamin D sufficient, deficient, and deficient but repleted. Biochemical parameters were measured preoperatively, after vitamin D replacement, at 1-month follow-up, and at 6-months follow-up.

RESULTS

Of 301 patients, 118 (39%) had a vitamin D level of 30 ng/mL or more; 71 patients (24%) were deficient, and 112 patients (37%) were vitamin D deficient but underwent repletion. The median duration of replacement was 28 days, and the dose of ergocalciferol was 400,000 U. Among the 112 patients who underwent repletion, the mean serum calcium remained relatively unchanged or decreased in 91 patients (81%). The gland size was smallest in patients with a preoperative sufficiency and largest in those deficient and not repleted. Postoperative PTH values at 1 month and at 6 months in the baseline-normal group were significantly less than in the other 2 groups (P = .05 and = .009, respectively), with no differences observed between the deficient and the deficient-repleted groups.

CONCLUSION

Preoperative Vit D replacement therapy was safe in PHPT patients and did not increase serum calcium levels. Vit D status affects gland size and postoperative PTH elevation. Repletion in this population is not durable.

The clinical content of preconception care: nutrition and dietary supplements

Women of child-bearing age should achieve and maintain good nutritional status prior to conception to help minimize health risks to both mothers and infants. Many women may not be aware of the importance of preconception nutrition and supplementation or have access to nutrition information. Health care providers should be knowledgeable about preconception/pregnancy-related nutrition and take the initiative to discuss this information during preconception counseling. Women of reproductive age should be counseled to consume a well-balanced diet including fruits and vegetables, iron and calcium-rich foods, and protein-containing foods as well as 400 microg of folic acid daily. More research is critically needed on the efficacy and safety of dietary supplements and the role of obesity in birth outcomes. Preconception counseling is the perfect opportunity for the health care provider to discuss a healthy eating guideline, dietary supplement intake, and maintaining a healthy weight status.

Expression of the vitamin d receptor is increased in the hypertrophic heart

The liganded vitamin D receptor (VDR) is thought to play an important role in controlling cardiac function. Specifically, this system has been implicated as playing an antihypertrophic role in the heart. Despite this, studies of VDR in the heart have been limited in number and scope. In the present study, we used a combination of real-time polymerase chain reaction, Western blot analysis, immunofluorescence, and transient transfection analysis to document the presence of functional VDR in both the myocytes and fibroblasts of the heart, as well as in the intact ventricular myocardium. We also demonstrated the presence of 1-alpha-hydroxylase and 24-hydroxylase in the heart, 2 enzymes involved in the synthesis and metabolism of 1,25 dihydroxyvitamin D. VDR is shown to interact directly with the human B-type natriuretic peptide gene promoter, a surrogate marker of the transcriptional response to hypertrophy. Of note, induction of myocyte hypertrophy either in vitro or in vivo leads to an increase in VDR mRNA and protein levels. Collectively, these findings suggest that the key components required for a functional 1,25 dihydroxyvitamin D-dependent signaling system are present in the heart and that this putatively antihypertrophic system is amplified in the setting of cardiac hypertrophy.

Hypovitaminosis D in obese and overweight schoolchildren

AIM

To determine the prevalence of vitamin D hypovitaminosis among obese and overweight schoolchildren.

DESIGN

A cross-sectional population based sample.

METHODS

In a cross-sectional study, 301 students (177 girls and 124 boys) aged 11-19 years were selected by multistage stratified sampling design. Subjects were classified according to their body mass index as obese, overweight and normal. Serum 25-hydroxyvitamin D (25-OHD), intact parathyroid hormone (iPTH) and alkaline phosphatase (ALP) were measured in late winter months. Vitamin D deficiency was defined as a 25-OHD 20 ng/ml.

RESULTS

The prevalence of hypovitaminosis D was found as 65% in all students. Vitamin D deficiency was found in 12% and insufficiency in 53% of all students. Vitamin D deficiency in female students was about two times more common than in males. In obese and overweight schoolchildren with hypovitaminosis D, serum 25-OHD levels decreased as BMI increased. There were no correlations between serum 25-OHD and ALP and iPTH levels.

CONCLUSION

Vitamin D deficiency and insufficiency are common in obese and overweight schoolchildren, especially in girls. Obesity could be a risk factor in terms of hypovitaminosis D in adolescents. Vitamin D supplementation should be administered particularly to adolescent girls.

Serum 25-hydroxyvitamin D status of the US population: 1988-1994 compared with 2000-2004

BACKGROUND

Changes in serum 25-hydroxyvitamin D [25(OH)D] concentrations in the US population have not been described.

OBJECTIVE

We used data from the National Health and Nutrition Examination Surveys (NHANES) to compare serum 25(OH)D concentrations in the US population in 2000-2004 with those in 1988-1994 and to identify contributing factors.

DESIGN

Serum 25(OH)D was measured with a radioimmunoassay kit in 20 289 participants in NHANES 2000-2004 and in 18 158 participants in NHANES III (1988-1994). Body mass index (BMI) was calculated from measured height and weight. Milk intake and sun protection were assessed by questionnaire. Assay differences were assessed by re-analyzing 150 stored serum specimens from NHANES III with the current assay.

RESULTS

Age-adjusted mean serum 25(OH)D concentrations were 5-20 nmol/L lower in NHANES 2000-2004 than in NHANES III. After adjustment for assay shifts, age-adjusted means in NHANES 2000-2004 remained significantly lower (by 5-9 nmol/L) in most males, but not in most females. In a study subsample, adjustment for the confounding effects of assay differences changed mean serum 25(OH)D concentrations by approximately 10 nmol/L, and adjustment for changes in the factors likely related to real changes in vitamin D status (ie, BMI, milk intake, and sun protection) changed mean serum 25(OH)D concentrations by 1-1.6 nmol/L.

CONCLUSIONS

Overall, mean serum 25(OH)D was lower in 2000-2004 than 1988-1994. Assay changes unrelated to changes in vitamin D status accounted for much of the difference in most population groups. In an adult subgroup, combined changes in BMI, milk intake, and sun protection appeared to contribute to a real decline in vitamin D status.

Novel antecedent plasma biomarkers of cardiovascular disease: improved evaluation methods and comparator benchmarks raise the bar

PURPOSE OF REVIEW

To assess recent advances in cardiovascular disease biomarkers, focusing on past failings, current promise, and areas for future work.

RECENT FINDINGS

Despite intense interest in novel biomarkers, few have yet to show utility in improving cardiovascular disease risk scores as assessed by predictive statistical models. Indeed, there is current debate as to how to evaluate clinical utility. There is increasing interest in biomarkers from pathophysiological pathways other than inflammation (cardiac signals, renal function, metabolic measures, novel lipids, nutritional, etc), as well as interest in combining such markers in panels to increase cardiovascular disease risk discrimination, and in 'omics' techniques. A challenge to the biomarker concept in cardiovascular disease is the contribution of other factors - for example, socioeconomic position or family history of premature cardiovascular disease - that present cheaper and more efficient way of gaining discrimination. Some have been added already to risk score guidelines in some countries. Whether novel plasma biomarkers can add further prediction requires study.

SUMMARY

The jury is still out on the ability of biomarkers to enhance risk scores in a cost-efficient way. New technologies and statistical models may optimize efforts but use of simpler lifestyle and demographic markers in recent risk scores revisions have raised the bar.

Automated Measurement of 25-OH Vitamin D3 on the Roche Modular E170 Analyzer

Background: The first commercial direct automated immunoassay specific for 25-OH vitamin D3 (25-OH-D3) was recently introduced for use on Roche Diagnostics immunoassay analyzers. We assessed the analytical performance of the Elecsys 25-OH-D3 assay on a Roche Modular E 170 analyzer.

Methods: The Elecsys 25-OH-D3 assay is a direct electrochemiluminescence immunoassay for human serum or plasma. It is a competitive assay in which the binding protein of vitamin D is inactivated during incubation. The assay employs a polyclonal antibody directed against 25-OH vitamin D3. We compared the 25-OH-D3 assay to assays performed with RIA, HPLC, and liquid chromatography–tandem mass spectrometry (LC-MS/MS).

Results: At concentrations of 48, 76, and 124 nmol/L, within-run CVs were 5.1%, 3.1%, and 7.1% and total CVs were 12.1%, 7.4%, and 10.6%, respectively. A comparison of Elecsys 25-OH vitamin D3 with RIA yielded the regression equation: Elecsys = 1.114 × RIA – 6.15 (Sy|x = 15.7 nmol/L; n = 163). The corresponding equation with HPLC was: Elecsys = 1.077 × HPLC + 5.442 (Sy|x = 13.9 nmol/L; n = 67) and with LC-MS/MS: Elecsys = 0.887 × LC-MS/MS + 5.046 (Sy|x =12.4 nmol/L; n = 64). Contrary to LC-MS/MS, with the cutoff of 50 nmol/L (deficiency vs normal), approximately 10% of samples were misclassified as normal with RIA and Elecsys. Plasma samples were observed to have markedly higher concentrations than serum samples.

Conclusions: The Elecsys concentrations of 25-OH-D3 were in good overall agreement with those determined with LC-MS/MS and RIA. However, large between-method variation was observed in individual patient samples. Use of serum rather than plasma is preferred owing to the higher results observed with plasma samples.

Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial

OBJECTIVES

The objective of the present study was to examine the cross-sectional relation between serum 25-hydroxyvitamin D [25-(OH) D] levels and depression in overweight and obese subjects and to assess the effect of vitamin D supplementation on depressive symptoms.

DESIGN

Cross-sectional study and randomized double blind controlled trial of 20,000 or 40,000 IU vitamin D per week versus placebo for 1 year.

SETTING

A total of 441 subjects (body mass index 28-47 kg m(-2), 159 men and 282 women, aged 21-70 years) recruited by advertisements or from the out-patient clinic at the University Hospital of North Norway.

MAIN OUTCOME MEASURES

Beck Depression Inventory (BDI) score with subscales 1-13 and 14-21.

RESULTS

Subjects with serum 25(OH)D levels < 40 nmol L(-1) scored significantly higher (more depressive traits) than those with serum 25(OH)D levels > or = 40 nmol L(-1) on the BDI total [6.0 (0-23) versus 4.5 (0-28) (median and range)] and the BDI subscale 1-13 [2.0 (0-15) versus 1.0 (0-29.5)] (P < 0.05). In the two groups given vitamin D, but not in the placebo group, there was a significant improvement in BDI scores after 1 year. There was a significant decrease in serum parathyroid hormone in the two vitamin D groups without a concomitant increase in serum calcium.

CONCLUSIONS

It appears to be a relation between serum levels of 25(OH)D and symptoms of depression. Supplementation with high doses of vitamin D seems to ameliorate these symptoms indicating a possible causal relationship.

Osteomalacia

The finding of low bone mineral density with a T-score of -2.5 or below on dual energy x-ray absorptiometry is usually reported as indicating that the patient has "osteoporosis" according to the World Health Organization classification, and, in postmenopausal women, it is often assumed that this is due to estrogen deficiency. However, up to one third of postmenopausal women have a secondary cause of low density, including osteomalacia. Osteomalacia is defined as a mineralization defect caused by disorders that lead to decreased mineralization of bone. Clues from the history, physical examination, laboratory tests, and radiographs may indicate that the patient suffers from a form of osteomalacia rather than postmenopausal estrogen deficiency alone. Establishing a diagnosis of osteomalacia when present is critical to proper management of the patient.

Does vitamin D make the world go 'round'?

Abstract Vitamin D has emerged from obscurity, and its effects on various organ systems throughout the body down to the cellular level are being discovered. What was once thought to be a simple hormone affecting only bone and calcium metabolism has shifted. We no longer see vitamin D as a "vitamin" important only in childhood, but as a complex hormone that is involved not only in calcium homeostasis but also in the integrity of the innate immune system. Vitamin D deficiency is linked to inflammatory and long-latency diseases such as multiple sclerosis, rheumatoid arthritis, tuberculosis, diabetes, and various cancers, to name a few. In this review, we trace how we came to view vitamin D and how that view led to one of the largest epidemics of nutrient deficiency beginning in the late 20(th) century. We then discuss the needs of vitamin D in the context of the breastfeeding mother and her infant and child, why breastfed infants are particularly at risk, and what to do about it.

The vitamin D deficiency pandemic and consequences for nonskeletal health: mechanisms of action

Vitamin D, the sunshine vitamin, is important for childhood bone health. Over the past two decades, it is now recognized that vitamin D not only is important for calcium metabolism and maintenance of bone health throughout life, but also plays an important role in reducing risk of many chronic diseases including type I diabetes, multiple sclerosis, rheumatoid arthritis, deadly cancers, heart disease and infectious diseases. How vitamin D is able to play such an important role in health is based on observation that all tissues and cells in the body have a vitamin D receptor, and, thus, respond to its active form 1,25-dihydroxyvitamin D. However, this did not explain how living at higher latitudes and being at risk of vitamin D deficiency increased risk of these deadly diseases since it was also known that the 1,25-dihydroxyvitamin D levels are normal or even elevated when a person is vitamin D insufficient. Moreover, increased intake of vitamin D or exposure to more sunlight will not induce the kidneys to produce more 1,25-dihydroxyvitamin D. The revelation that the colon, breast, prostate, macrophages and skin among other organs have the enzymatic machinery to produce 1,25-dihydroxyvitamin D provides further insight as to how vitamin D plays such an essential role for overall health and well being. This review will put into perspective many of the new biologic actions of vitamin D and on how 1,25-dihydroxyvitamin D is able to regulate directly or indirectly more than 200 different genes that are responsible for a wide variety of biologic processes.

Plasma 25-hydroxyvitamin D levels in young children undergoing placement of tympanostomy tubes

OBJECTIVES

We report the plasma 25-hydroxyvitamin D [25(OH)D] levels of 16 young children who were undergoing ambulatory surgery for placement of tympanostomy tubes.

METHODS

We previously obtained blood samples from young children who were undergoing ambulatory surgery and reported that they had lower blood levels than adults of eicosapentaenoic acid (an omega-3 fatty acid), vitamin A, and selenium. Plasma frozen continuously at -80 degrees C was available from 16 subjects who were undergoing placement of tympanostomy tubes.

RESULTS

The mean (+/- SD) age of the patients was 3.7 +/- 1.6 years (median, 2.9 years; range, 1.9 to 7.4 years). Sixty-two percent were male; half were white, and half were Hispanic. Sixty-two percent were private patients; the parents reported that half were taking vitamin supplements. None had a history of rickets. None had 25(OH)D levels less than 10 ng/mL; 50% had 25(OH)D levels less than 20 ng/mL (deficient in adults); another 31% had levels from 21 to 29 ng/mL (insufficient in adults).

CONCLUSIONS

Vitamin D is essential for the production of endogenous antimicrobial peptides, and has been linked to seasonal, epidemic influenza A. However, the level of 25(OH)D needed to prevent infection with various human pathogens has not been defined. In view of increasing bacterial resistance and emerging new pathogens, further research on the relationship of infection to 25(OH)D and other nutritional factors is warranted.

Nutritional biochemistry of spaceflight

As we approach the end of the first 50 years of human space travel, much has been learned about adaptation to microgravity and the risks associated with extended-duration space exploration. As the frequency and duration of flights grew, nutrition issues became more critical and the questions to be answered became more complex: What are the nutrient requirements for space travelers? Can nutrients be used as tools to mitigate the negative effects of space travel on humans? How does nutrition interrelate with other physiological systems (such as muscle, bone, and cardiovascular system) and their adaptation to microgravity? Much research has been done over the decades in both actual spaceflight and ground-based analogs. We review here much of what is known, and highlight areas of ongoing research and concerns for future exploration of the Moon, Mars, and beyond.

Recommended nutritional supplements for bariatric surgery patients

OBJECTIVE

To review nutritional supplements commonly required after bariatric surgery to provide a practical guide and reference source for generalist healthcare providers.

DATA SOURCES

A PubMed literature search (1988-July 2008) was conducted, using the search term nutritional deficiency after bariatric surgery, and was limited to English-language literature on adult (aged >19 y) human subjects. Additional references from the selected literature were also included.

STUDY SELECTION AND DATA EXTRACTION

Data were extracted from large clinical series and practice guidelines whenever possible. Case reports were used only when they were the sole information source.

DATA SYNTHESIS

Nutritional deficiencies that occur after bariatric surgery depend significantly on the type of surgery performed. Restrictive procedures such as gastric banding are the least likely to cause nutritional deficits, since none of the intestine is bypassed. Malabsorptive procedures such as biliopancreatic diversion or mixed restrictive/malabsorptive procedures (eg, Roux-en-Y gastric bypass) can result in serious nutritional problems when patients do not take required supplements after surgery. Vitamins and minerals that are commonly deficient in this circumstance include vitamin B(12), calcium, vitamin D, thiamine, folic acid, iron, zinc, and magnesium. Rare ocular complications have been reported with hypovitaminosis A.

CONCLUSIONS

Healthcare professionals, especially those who practice outside large bariatric centers, must be aware of the supplements required by patients who have had bariatric surgery. Many patients fail to follow up with the surgery centers and are managed by their primary care teams and community pharmacists, especially in the selection of multivitamin and nutritional supplements.

Maternal plasma 25-hydroxyvitamin D concentrations and the risk for gestational diabetes mellitus

Background

Evidence is accumulating for a role of vitamin D in maintaining normal glucose homeostasis. However, studies that prospectively examined circulating concentrations of 25-hydroxyvitamin D (25-[OH] D) in relation to diabetes risk are limited. Our objective is to determine the association between maternal plasma 25-[OH] D concentrations in early pregnancy and the risk for gestational diabetes mellitus (GDM).

Methods

A nested case-control study was conducted among a prospective cohort of 953 pregnant women. Among them, 57 incident GDM cases were ascertained and 114 women who were not diagnosed with GDM were selected as controls. Controls were frequency matched to cases for the estimated season of conception of the index pregnancy.

Results

Among women who developed GDM, maternal plasma 25-[OH] D concentrations at an average of 16 weeks of gestation were significantly lower than controls (24.2 vs. 30.1 ng/ml, P<0.001). This difference remained significant (3.62 ng/ml lower on average in GDM cases than controls (P value = 0.018)) after the adjustment for maternal age, race, family history of diabetes, and pre-pregnancy BMI. Approximately 33% of GDM cases, compared with 14% of controls (P<0.001), had maternal plasma 25-[OH] D concentrations consistent with a pre-specified diagnosis of vitamin D deficiency (<20 ng/ml). After adjustment for the aforementioned covariates including BMI, vitamin D deficiency was associated with a 2.66-fold (OR (95% CI): 2.66 (1.01–7.02)) increased GDM risk. Moreover, each 5 ng/ml decrease in 25-[OH] D concentrations was related to a 1.29-fold increase in GDM risk (OR (95% CI): 1.29 (1.05–1.60)). Additional adjustment for season and physical activity did not change findings substantially.

Conclusions

Findings from the present study suggest that maternal vitamin D deficiency in early pregnancy is significantly associated with an elevated risk for GDM.

IL-15 links TLR2/1-induced macrophage differentiation to the vitamin D-dependent antimicrobial pathway

An essential function of the innate immune system is to directly trigger antimicrobial mechanisms to defend against invading pathogens. In humans, one such pathway involves activation by TLR2/1L leading to the vitamin D-dependent induction of antimicrobial peptides. In this study, we found that TLR2/1-induced IL-15 was required for induction of CYP27b1, the VDR and the downstream antimicrobial peptide cathelicidin. Although both IL-15 and IL-4 triggered macrophage differentiation, only IL-15 was sufficient by itself to induce CYP27b1 and subsequent bioconversion of 25-hydroxyvitamin D3 (25D3) into bioactive 1,25D3, leading to VDR activation and induction of cathelicidin. Finally, IL-15-differentiated macrophages could be triggered by 25D3 to induce an antimicrobial activity against intracellular Mycobacterium tuberculosis. Therefore, IL-15 links TLR2/1-induced macrophage differentiation to the vitamin D-dependent antimicrobial pathway.

Respiratory epithelial cells convert inactive vitamin D to its active form: potential effects on host defense

The role of vitamin D in innate immunity is increasingly recognized. Recent work has identified a number of tissues that express the enzyme 1alpha-hydroxylase and are able to activate vitamin D. This locally produced vitamin D is believed to have important immunomodulatory effects. In this paper, we show that primary lung epithelial cells express high baseline levels of activating 1alpha-hydroxylase and low levels of inactivating 24-hydroxylase. The result of this enzyme expression is that airway epithelial cells constitutively convert inactive 25-dihydroxyvitamin D(3) to the active 1,25-dihydroxyvitamin D(3). Active vitamin D that is generated by lung epithelium leads to increased expression of vitamin D-regulated genes with important innate immune functions. These include the cathelicidin antimicrobial peptide gene and the TLR coreceptor CD14. dsRNA increases the expression of 1alpha-hydroxylase, augments the production of active vitamin D, and synergizes with vitamin D to increase expression of cathelicidin. In contrast to induction of the antimicrobial peptide, vitamin D attenuates dsRNA-induced expression of the NF-kappaB-driven gene IL-8. We conclude that primary epithelial cells generate active vitamin D, which then influences the expression of vitamin D-driven genes that play a major role in host defense. Furthermore, the presence of vitamin D alters induction of antimicrobial peptides and inflammatory cytokines in response to viruses. These observations suggest a novel mechanism by which local conversion of inactive to active vitamin D alters immune function in the lung.

25-Hydroxyvitamin D deficiency is independently associated with cardiovascular disease in the Third National Health and Nutrition Examination Survey

OBJECTIVE

Serum 25-hydroxyvitamin D [25(OH)D] levels are inversely associated with important cardiovascular disease (CVD) risk factors. However, the association between 25(OH)D levels and prevalent CVD has not been extensively examined in the general population.

METHODS

We performed a cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey (1988-1994) and examined the association between serum 25(OH)D levels and prevalence of CVD in a representative population-based sample of 16,603 men and women aged 18 years or older. Prevalence of CVD was defined as a composite measure inclusive of self-reported angina, myocardial infarction or stroke.

RESULTS

In the whole population, there were 1308 (8%) subjects with self-reported CVD. Participants with CVD had a greater frequency of 25(OH)D deficiency [defined as serum 25(OH)D levels <20 ng/mL] than those without (29.3% vs. 21.4%; p<0.0001). After adjustment for age, gender, race/ethnicity, season of measurement, physical activity, body mass index, smoking status, hypertension, diabetes, elevated low-density lipoprotein cholesterol, hypertriglyceridemia, low high-density lipoprotein cholesterol, chronic kidney disease and vitamin D use, participants with 25(OH)D deficiency had an increased risk of prevalent CVD (odds ratio 1.20 [95% confidence interval (CI) 1.01-1.36; p=0.03]).

CONCLUSIONS

These results indicate a strong and independent relationship of 25(OH)D deficiency with prevalent CVD in a large sample representative of the US adult population.

Association between quantitative measures of skin color and plasma 25-hydroxyvitamin D

We examined the relationship between vitamin D and skin color measured by reflectance colorimetry at an exposed and un-exposed site in 321 people. Exposed but not unexposed skin color was associated with better vitamin D status. Sun-exposure was more important than natural skin color in determining vitamin D status in our population.

INTRODUCTION

Vitamin D is obtained through UV synthesis in the skin where melanin limits its synthesis. Ethnicity is often used as a proxy for skin color, but skin color varies considerably. The relation between quantitative measures of skin color and plasma 25-hydroxyvitamin D (25OHD) concentration has not been well described.

METHODS

The aim of this study was to determine the association between constitutive (natural) and sun-induced skin color and 25OHD in a group of Pacific People (n = 87) and Europeans (n = 255) living in NZ (46 degrees S) in summer. Plasma 25OHD was determined and sun-induced (outer fore-arm) and constitutive (upper inner-arm) measured by reflectance colorimetry.

RESULTS

Mean (SD) 25OHD was significantly higher in Europeans than Pacific People, 88 (31) nmol/L vs. 75 (34) nmol/L, respectively. Based on constitutive skin color, 35% of participants were very light, 45% light, 16% intermediate, 4% tanned, and 0% brown or dark. Skin color at the forearm but not constitutive skin color was a significant predictor of 25OHD. Each 10 degrees lower skin color value at the forearm (more tanning) was associated with a 5 nmol/L higher 25OHD (P < 0.001).

CONCLUSIONS

Tanning but not natural skin color was an important determinant of 25OHD. Further study is needed in a population with a higher proportion of darker skin people.

Plasma 25-hydroxyvitamin D levels and risk of incident hypertension among young women

Numerous cross-sectional studies demonstrate an inverse association between plasma 25-hydroxyvitamin D [25(OH)D] and blood pressure or hypertension. Prospective data, however, are limited. Among 1484 women aged 32 to 52 years who did not have hypertension at baseline, we prospectively analyzed the association between plasma levels of 25(OH)D and the odds of incident hypertension using a nested case-control study design. We matched cases and controls on age, race, and month of blood collection and further adjusted for body mass index, physical activity, family history of hypertension, oral contraceptive use, and plasma levels of parathyroid hormone, calcium, phosphorous, creatinine, and uric acid. Median plasma 25(OH)D levels were lower in the cases (25.6 ng/mL) than in the controls (27.3 ng/mL; P<0.001). Women in the lowest compared with highest quartile of plasma 25(OH)D had an adjusted odds ratio for incident hypertension of 1.66 (95% CI: 1.11 to 2.48; P for trend=0.01). Compared with women with sufficient levels, those with vitamin D deficiency (<30 ng/mL; 65.7% of the study population) had a multivariable odds ratio of 1.47 (95% CI: 1.10 to 1.97). Plasma 25(OH)D levels are inversely and independently associated with the risk of developing hypertension.

Hypovitaminosis D and secondary hyperparathyroidism in resident physicians of a general hospital in southern Brazil

OBJECTIVES

To evaluate the prevalence of hypovitaminosis D and secondary hyperparathyroidism in resident physicians of a general hospital in southern Brazil and identify associated factors.

DESIGN

Cross-sectional study.

POPULATION

Resident physicians of Hospital de Clinicas de Porto Alegre, Porto Alegre, southern Brazil.

PARTICIPANTS

Seventythree subjects age 26.4+/-1.9.

MEASUREMENTS

Serum PTH, 25- hydroxyvitamin D [25(OH)D], total calcium, phosphorus, magnesium, creatinine, and alkaline phosphatase were measured. In addition calcium, creatinine, and magnesium were measured in urine. Fractional excretion of calcium and magnesium were calculated. Calcium intake was estimated by a food intake questionnaire.

RESULTS

Mean serum levels of 25(OH)D were 17.9+/-8.0 ng/ml and 57.4% presented 25(OH)D below 20 ng/ml. Secondary hyperparathyroidism, defined as serum PTH > or =48 pg/ml and normal or low serum calcium, was identified in 39.7% of the individuals. Mean serum levels of magnesium were higher (p=0.02) and the fractional excretion of calcium was lower (p<0.001) in individuals with secondary hyperparathyroidism. Serum PTH levels were positively correlated with body mass index (r=0.33 and p=0.006) and serum magnesium levels (r=0.33 and p=0.02) and negatively correlated with serum 25(OH)D levels (r=-0.33 and p=0.008), estimated calcium intake (r=-0.25 and p=0.04), and fractional excretion of calcium (r=-0.34 and p=0.009).

CONCLUSION

Vitamin D deficiency and secondary hyperparathyroidism was very common in resident physicians. Therefore, measures to prevent this situation should be recommended.