Vitamin D deficiency

Clinical management of disturbances of calcium and phosphate metabolism in dialysis patients

Management of chronic kidney disease–mineral bone disorder can be difficult in renal patients. This review aims to explain why the control of disturbed calcium, phosphate, parathyroid hormone and vitamin D metabolism is important in dialysis patients. The methods available to regulate these parameters include diet, phosphate binders, dialysate calcium, native vitamin D, active vitamin D derivatives and calcimimetics. An overview of current treatment guidelines will be discussed.

Ageing and vitamin D deficiency: effects on calcium homeostasis and considerations for vitamin D supplementation

Vitamin D is a fat-soluble, seco-steroid hormone. In man, the vitamin D receptor is expressed in almost all tissues, enabling effects in multiple systems of the human body. These effects can be endocrine, paracrine and autocrine. The present review summarises the effects of ageing on the vitamin D endocrine system and on Ca homeostasis. Furthermore, consequences for vitamin D supplementation are discussed.

Alterations in vitamin D status and anti-microbial peptide levels in patients in the intensive care unit with sepsis

BACKGROUND

Vitamin D insufficiency is common in hospitalized patients. Recent evidence suggests that vitamin D may enhance the innate immune response by induction of cathelicidin (LL-37), an endogenous antimicrobial peptide produced by macrophages and neutrophils. Thus, the relationship between vitamin D status and LL-37 production may be of importance for host immunity, but little data is available on this subject, especially in the setting of human sepsis syndrome and other critical illness.

METHODS

Plasma concentrations of 25-hydroxyvitamin D (25(OH)D), vitamin D binding protein (DBP) and LL-37 in critically ill adult subjects admitted to intensive care units (ICUs) with sepsis and without sepsis were compared to healthy controls.

RESULTS

Critically ill subjects had significantly lower plasma 25(OH)D concentrations compared to healthy controls. Mean plasma LL-37 levels were significantly lower in critically ill subjects compared to healthy controls. Vitamin D binding protein levels in plasma were significantly lower in critically ill subjects with sepsis compared to critically ill subjects without sepsis. There was a significant positive association between circulating 25(OH)D and LL-37 levels.

CONCLUSION

This study demonstrates an association between critical illness and lower 25(OH)D and DBP levels in critically ill patients as compared to healthy controls. It also establishes a positive association between vitamin D status and plasma LL-37, which suggests that systemic LL-37 levels may be regulated by vitamin D status. Optimal vitamin D status may be important for innate immunity especially in the setting of sepsis. Further invention studies to examine this association are warranted.

Vitamin D2 formation and bioavailability from Agaricus bisporus button mushrooms treated with ultraviolet irradiation

Agaricus bisporus mushrooms contain an abundance of ergosterol, which on exposure to UV irradiation is converted to vitamin D2. The present study evaluated the effects UV-C irradiation on vitamin D2 formation and its bioavailability in rats. Fresh button mushrooms were exposed to UV-C irradiation at mean intensities of 0.403, 0.316, and 0.256 mW/cm(2) from respective distances of 30, 40, and 50 cm for periods ranging from 2.5 to 60 min. Vitamin D2 and ergosterol were measured by HPLC-MS/MS. The stability and retention of vitamin D2 were assessed including the extent of discoloration during storage at 4 degrees C or at room temperature. Exposure to UV-C irradiation at 0.403 mW/cm(2) intensity from 30 cm distance resulted in a time-dependent increase in vitamin D2 concentrations that was significantly higher than those produced at intensities of 0.316 and 0.256 mW/cm(2) from distances of 40 and 50 cm, respectively. Furthermore, the concentrations of vitamin D2 produced after exposure to UV-C irradiation doses of 0.125 and 0.25 J/cm(2) for, 2.5, 5, and 10 min were 6.6, 15.6, and 23.1 microg/g solids, equivalent to 40.6, 95.4, and 141 microg/serving, respectively. The data showed a high rate of conversion from ergosterol to vitamin D2 at short treatment time, which is required by the mushroom industry. The stability of vitamin D2 remained unchanged during storage at 4 degrees C and at room temperature over 8 days (P = 0.36), indicating no degradation of vitamin D2. By visual assessment or using a chromometer, no significant discoloration of irradiated mushrooms, as measured by the degree of "whiteness", was observed when stored at 4 degrees C compared to that observed with mushrooms stored at room temperature over an 8 day period (P < 0.007). Vitamin D2 was well absorbed and metabolized as evidenced by the serum response of 25-hydroxyvitamin D in rats fed the irradiated mushrooms. Taken together, the data suggest that commercial production of button mushrooms enriched with vitamin D2 for improving consumer health may be practical.

Vitamin D status and effect of low-dose cholecalciferol and high-dose ergocalciferol supplementation in multiple sclerosis

BACKGROUND

Vitamin D is important for bone health and immune regulation, and has been shown to be low in multiple sclerosis (MS). We sought to determine the effect of over the counter low dose cholecalciferol (LDC) and high dose ergocalciferol (HDE) on the vitamin D levels in MS patients.

METHODS

We retrospectively evaluated serum 25-hydroxy-vitamin D [25(OH)D] levels of 199 patients (CIS, n = 32; RRMS, n = 115; PPMS, n = 10; SPMS, n = 16; Transverse Myelitis (TM), n = 9; other neurological diseases, n = 16) attending our clinic between 2004 and 2008. We examined the change in 25(OH)D levels in 40 MS patients who took either LDC (< or =800 IU/day) or HDE (50,000 IU/day for 7-10 days, followed by 50,000 IU weekly or biweekly).

RESULTS

The average 25(OH)D level was 71 +/- 39 nmol/L (Mean +/- SD), and 167(84%) patients had insufficient levels (< or =100 nmol/L) of 25(OH)D. The patients supplemented with LDC did not have a significant increase in their 25(OH)D levels. However, 25(OH)D levels increased by 42 nmol/L (P = 0.01) in the patients originally taking LDC and then prescribed HDE. Optimal levels (> or =100 nmol/L) were only achieved in less than 40% of patients.

CONCLUSIONS

We conclude that large numbers of patients with MS and TM in our cohort are deficient in vitamin D. HDE significantly elevated 25(OH)D levels in MS patients and was more effective at increasing 25(OH)D levels than LDC. Prospective studies are required to determine appropriate dosing regimen to achieve optimal levels in the majority of MS patients and to ascertain the safety, immunological response, and ultimately the clinical efficacy of vitamin D replacement therapy.

Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004

BACKGROUND

Vitamin D insufficiency is associated with suboptimal health. The prevalence of vitamin D insufficiency may be rising, but population-based trends are uncertain. We sought to evaluate US population trends in vitamin D insufficiency.

METHODS

We compared serum 25-hydroxyvitamin D (25[OH]D) levels from the Third National Health and Nutrition Examination Survey (NHANES III), collected during 1988 through 1994, with NHANES data collected from 2001 through 2004 (NHANES 2001-2004). Complete data were available for 18 883 participants in NHANES III and 13 369 participants in NHANES 2001-2004.

RESULTS

The mean serum 25(OH)D level was 30 (95% confidence interval [CI], 29-30) ng/mL during NHANES III and decreased to 24 (23-25) ng/mL during NHANES 2001-2004. Accordingly, the prevalence of 25(OH)D levels of less than 10 ng/mL increased from 2% (95% CI, 2%-2%) to 6% (5%-8%), and 25(OH)D levels of 30 ng/mL or more decreased from 45% (43%-47%) to 23% (20%-26%). The prevalence of 25(OH)D levels of less than 10 ng/mL in non-Hispanic blacks rose from 9% during NHANES III to 29% during NHANES 2001-2004, with a corresponding decrease in the prevalence of levels of 30 ng/mL or more from 12% to 3%. Differences by age strata (mean serum 25[OH]D levels ranging from 28-32 ng/mL) and sex (28 ng/mL for women and 32 ng/mL for men) during NHANES III equalized during NHANES 2001-2004 (24 vs 24 ng/mL for age and 24 vs 24 ng/mL for sex).

CONCLUSIONS

National data demonstrate a marked decrease in serum 25(OH)D levels from the 1988-1994 to the 2001-2004 NHANES data collections. Racial/ethnic differences have persisted and may have important implications for known health disparities. Current recommendations for vitamin D supplementation are inadequate to address the growing epidemic of vitamin D insufficiency.

Is vitamin D deficiency involved in the immune reconstitution inflammatory syndrome?

Background

About 20–30% of persons with HIV infection, especially those living in countries with limited resources, experience an immune reconstitution inflammatory syndrome (IRIS) after starting antiretroviral treatment. The active form of vitamin D, 1,25-dihydroxyvitamin D, is a key player in the clearance of pathogens and influences the level of inflammation and macrophage activation.

Presentation of the hypothesis

We hypothesize that low availability of 1,25-dihydroxyvitamin D, either due to vitamin D deficiency or due to polymorphisms in the vitamin D receptor or in its activating/inactivating enzymes, contributes to the appearance of IRIS. Furthermore, drug interactions with the enzymatic pathways of vitamin D could favour the development of IRIS.

Testing the hypothesis

Our hypothesis could be explored by a case-control study to assess the prevalence of vitamin D deficiency in HIV-infected patients on antiretroviral treatment who develop and do not develop IRIS.

Implications of the hypothesis

If the role of vitamin D in IRIS is confirmed, we would be able to screen patients at risk for IRIS by screening for vitamin D deficiency. After confirmation by means of a clinical trial, vitamin D supplementation could be a cheap and safe way to reduce the incidence of IRIS.

Circulating calcitriol concentrations and total mortality

BACKGROUND

Evidence is accumulating that vitamin D supplementation of patients with low 25-hydroxyvitamin D concentrations is associated with lower cardiovascular morbidity and total mortality during long-term follow-up. Little is known, however, about the effect of low concentrations of the vitamin D hormone calcitriol on total mortality. We therefore evaluated the predictive value of circulating calcitriol for midterm mortality in patients of a specialized heart center.

METHODS

This prospective cohort study included 510 patients, 67.7% with heart failure (two-thirds in end stage), 64.3% hypertension, 33.7% coronary heart disease, 20.2% diabetes, and 17.3% renal failure. We followed the patients for up to 1 year after blood collection. For data analysis, the study cohort was stratified into quintiles of circulating calcitriol concentrations.

RESULTS

Patients in the lowest calcitriol quintile were more likely to have coronary heart disease, heart failure, hypertension, diabetes, and renal failure compared to other patients. They also had low 25-hydroxyvitamin D concentrations and high concentrations of creatinine, C-reactive protein, and tumor necrosis factor alpha. Eighty-two patients (16.0%) died during follow-up. Probability of 1-year survival was 66.7% in the lowest calcitriol quintile, 82.2% in the second quintile, 86.7% in the intermediate quintile, 88.8% in the fourth quintile, and 96.1% in the highest quintile (P < 0.001). Discrimination between survivors and nonsurvivors was best when a cutoff value of 25 ng/L was applied (area under the ROC curve 0.72; 95% CI 0.66-0.78).

CONCLUSIONS

Decreased calcitriol levels are linked to excess midterm mortality in patients of a specialized heart center.

The vitamin D status among Tibetans

UVB from the sun and intake from food are the only human sources of vitamin D. Tibet is a unique region for comparisons of these sources: (1) it lies at a low latitude and at a high altitude and has very large annual fluences of UVB; (2) the traditional Tibetan food is poor in vitamin D. Blood samples were taken from 63 persons of different age, with different occupations and staying at different places. UVB doses at these places were measured. The samples were analyzed by a standard radioimmune assay for determination of the serum concentration of 25 hydroxyvitamin D (25(OH)D). The main finding was that among nomads, there seems to be severe vitamin D deficiency (serum levels of 25(OH)D<30 nM). We tentatively propose that the low level of 25(OH)D of nomads is related to their clothing and sun exposure habits. For persons of other occupations (students, teachers and farmers) the levels are higher, although a significant fraction of these persons also have lower levels than 75 nm, by many regarded as a limit for insufficiency related to a number of negative health conditions. The annual dose of vitamin D-generating UVB is about five times larger in Lhasa than in Oslo. Despite this, the average vitamin D status seems to be similar, except in the case of nomads. This phenomenon is certainly related to food habits. In conclusion, the 25(OH)D status among nomads in Tibet appears to be alarmingly low. However, for people of other occupations the status is more normal.

No difference between strontium ranelate (SR) and calcium/vitamin D on bone turnover markers in women with established osteoporosis previously treated with teriparatide: a randomized controlled trial

Objective To evaluate the effect of strontium ranelate (SR) on bone turnover markers in women with established osteoporosis previously treated with teriparatide (TPTD--recombinant human PTH 1-34). DESIGN PATIENTS: Twenty-two postmenopausal Caucasian women (aged 65.7 +/- 1.7 years) with established osteoporosis previously treated with TPTD 20 microg daily for 18 months were randomly assigned to receive either SR (SR group, n = 11) or calcium and vitamin D (control group, n = 11).

MEASUREMENTS

Blood samples for serum N-terminal propeptide of type 1 collagen (P1NP), C-terminal telopeptide of type 1 collagen (CTx) and total alkaline phosphatase (ALP) were obtained from all women before (pre-TPTD) and after (post-TPTD) TPTD administration, as well as 6 months after SR or calcium/vitamin D administration (post-SR/Ca).

RESULTS

Serum P1NP, CTx and total ALP increased significantly after TPTD treatment and decreased at the end of the study in both SR and control groups, with no difference between them.

CONCLUSIONS

SR following TPTD administration acts predominantly as an antiresorptive agent with no evidence of additional osteoanabolic action. In this setting, SR is not more effective than Ca/vitamin D as far as bone turnover markers are concerned.

Management of osteoporosis among home health and long-term care patients with a prior fracture

Osteoporosis is a growing health concern as the number of senior adults continues to increase worldwide. Falls and fractures are very common among frail older adults requiring home health and long-term care. Preventative strategies for reducing falls have been identified and many therapies (both prescription and nonprescription) with proven efficacy for reducing fracture risk are available. However, many practitioners overlook the fact that a fragility fracture is diagnostic for osteoporosis even without knowledge of bone mineral density testing. As a result, osteoporosis is infrequently diagnosed and treated in the elderly after a fracture. Based on existing literature, we have developed an algorithm for the assessment and treatment of osteoporosis among persons with known prior fracture(s) living in long-term care facilities or receiving home health care based on the data available in the literature.

Vitamin d-directed rheostatic regulation of monocyte antibacterial responses

The active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)(2)D) enhances innate immunity by inducing the cathelicidin antimicrobial peptide (hCAP). In monocytes/macrophages, this occurs primarily in response to activation of TLR, that induce expression of the vitamin D receptor and localized synthesis of 1,25(OH)(2)D from precursor 25-hydroxyvitamin D(3) (25OHD). To clarify the relationship between vitamin D and innate immunity, we assessed changes in hCAP expression in vivo and ex vivo in human subjects attending a bone clinic (n = 50). Of these, 38% were vitamin D-insufficient (<75 nM 25OHD) and received supplementation with vitamin D (50,000 IU vitamin D(2) twice weekly for 5 wk). Baseline 25OHD status or vitamin D supplementation had no effect on circulating levels of hCAP. Therefore, ex vivo changes in hCAP for each subject were assessed using peripheral blood monocytes cultured with 10% autologous serum (n = 28). Under these vitamin D "insufficient" conditions the TLR2/1 ligand 19 kDa lipopeptide or the TLR4 ligand LPS, monocytes showed increased expression of the vitamin D-activating enzyme CYP27b1 (5- and 5.5-fold, respectively, both p < 0.01) but decreased expression of hCAP mRNA (10-fold and 30-fold, both p < 0.001). Following treatment with 19 kDa, expression of hCAP: 1) correlated with 25OHD levels in serum culture supplements (R = 0.649, p < 0.001); 2) was significantly enhanced by exogenous 25OHD (5 nM); and 3) was significantly enhanced with serum from vivo vitamin D-supplemented patients. These data suggest that a key role of vitamin D in innate immunity is to maintain localized production of antibacterial hCAP following TLR activation of monocytes.

Does an active sun exposure habit lower the risk of venous thrombotic events? A D-lightful hypothesis

BACKGROUND

Venous and arterial thrombotic complications exhibit a seasonal variation, with risk peaking in winter and dropping to a nadir in summer. We sought a possible correlation between sun exposure habits and venous thromboembolism (VTE) events.

METHODS

This was a cohort study comprising 40,000 women (1000 per year of age from 25 to 64 years) who were drawn from the southern Swedish population registry for 1990 and followed for a mean of 11 years. Seventy-four per cent answered an inquiry at the inception of the study (n=29,518), and provided detailed information on their sun exposure habits. Cox regression analysis was used with the presence of VTE as a dependent variable and selected demographics as independent variables. The main outcome was the relationship between VTE and sun exposure habits.

RESULTS

Swedish women who sunbathed during the summer, on winter vacations, or when abroad, or used a tanning bed, were at 30% lower risk of VTE than those who did not. Risk estimates did not change substantially after adjustment for demographic variables. The risk of VTE increased by 50% in winter as compared to the other seasons; the lowest risk was found in the summer.

CONCLUSIONS

Women with more active sun exposure habits were at a significantly lower risk of VTE. We speculate that greater ultraviolet B light exposure improves a person's vitamin D status, which in turn enhances anticoagulant properties and enhances the cytokine profile.

Treatment of osteopenia and osteoporosis in anorexia nervosa: a systematic review of the literature

OBJECTIVE

To systematically review the evidence supporting treatment of osteopenia and osteoporosis in patients with anorexia nervosa (AN).

DATA SOURCES

We identified controlled clinical studies of interventions for low bone mass in AN via searches of MEDLINE; the Cochrane Library; EMBASE; PsycINFO; and cumulative index to nursing and allied health literature. Outcomes of interest were changes in bone mineral density and fracture incidence.

RESULTS

Six randomized controlled trials (RCTs) and two cohort trials examined five classes of medical therapy on bone mineral density outcomes. One RCT of bisphosphonates showed no benefit and a second flawed RCT showed some benefit; one RCT showed a benefit of insulin-like growth factor-I; none of the five trials evaluating estrogen therapy showed benefit.

DISCUSSION

Although patients with AN are often losing bone mass when they should be optimizing bone growth, there is no good evidence to guide medicinal interventions. Therefore, early detection and weight restoration are of utmost importance whereas ongoing trials define effective therapies.

Alendronate/vitamin D3 70 mg/2800 IU with and without additional 2800 IU vitamin D3 for osteoporosis: results from the 24-week extension of a 15-week randomized, controlled trial

Although vitamin D supplementation is a fundamental part of osteoporosis treatment, many patients do not regularly take adequate amounts. A once-weekly (OW) alendronate (ALN) preparation that includes 2800 IU of vitamin D3 in a single combination tablet (ALN+D2800) is available for treating patients and ensuring intake of vitamin D that is consistent with existing guidelines. This randomized, double-blind study extension was conducted to evaluate the safety and tolerability of ALN+D2800 and ALN+D2800 plus an additional 2800 IU vitamin D3 single tablet supplement (ALN+D5600) administered for 24 weeks in men and postmenopausal women with osteoporosis previously treated OW for 15 weeks with either ALN or ALN+D2800. The primary endpoint was the proportion of participants who developed hypercalciuria (defined as a 24-hour urine calcium >300 mg in women or >350 mg in men and an increase of >25% versus randomization baseline) at week 39. The key secondary endpoint was the proportion of participants with vitamin D insufficiency (serum 25(OH)D <15 ng/mL [37.4 nmol/L]) at the end of the study. Hypercalciuria incidence (4.2% [ALN+D5600] vs. 2.8% [ALN+D2800]), did not differ between groups (p = 0.354). No participants developed hypercalcemia. Among the participants with vitamin D insufficiency at the week 0 baseline, the prevalence of insufficiency at the end of the study was reduced by 92% in the ALN+D5600 group and by 86% in the ALN+D2800 group. The incidences of clinical adverse experiences, including drug-related adverse experiences, were similar in both groups. In subjects previously treated with ALN+D2800 for 15 weeks, the addition of 2800 IU D3 for 24 weeks did not produce hypercalcemia nor increase the risk of hypercalciuria.

Influence of obesity on vitamin D-binding protein and 25-hydroxy vitamin D levels in African American and white women

25-Hydroxy vitamin D (25OHD) is lipophilic and highly bound to vitamin D-binding protein (VDBP) in plasma. In the present study, we examined VDBP and 25OHD levels by race and body mass index (BMI) in young adult women to determine whether circulating VDBP plays a role in the low levels of 25OHD with obesity and among African Americans. In agreement with previous studies, mean 25OHD levels were lower in African American women than in whites (P < .01). In a hierarchical multiple regression model, BMI was associated with 25OHD after adjustment for age in white women (P = .02, R(2) = .10) but not in African American women. The VDBP levels, by contrast, were similar in African Americans and whites, and were unrelated to BMI in either racial group. Furthermore, VDBP was unrelated to the plasma level of 25OHD. These data confirm an interaction between race and obesity in vitamin D metabolism, and imply that the carrier protein is not an important determinant of circulating 25OHD in women, nor is it affected by race or adiposity.

Serum 25-hydroxyvitamin D and IgE - a significant but nonlinear relationship

BACKGROUND

Hormonal vitamin D system affects the determination of T-cell responses. It is unknown if there is an association between vitamin D status and allergic conditions. Our aim was to investigate differences in serum IgE concentrations by vitamin D status [measured by 25(OH)D] and by a genetic variation in a key vitamin D activation enzyme (CYP27B1) previously shown to be associated with type 1 diabetes.

METHODS

9377 participants in the 1958 British birth cohort completed a biomedical assessment at 45 years of age ; 7288 eligible participants had data on 25(OH)D and IgE, with 6429 having further information on CYP27B1 genotype ()1260C>A).

RESULTS

There was a nonlinear association between 25(OH)D and IgE (P-value for curvature = 0.0001). Compared with the reference group with the lowest IgE concentrations [25(OH)D 100-125 nmol/l], IgE concentrations were 29% higher (95% CI 9-48%) for participants with the 25(OH)D <25 nmol/l, and 56% higher (95% CI 17-95%) for participants with 25(OH)D >135 nmol/l (adjusted for sex, month, smoking, alcohol consumption, time spent outside, geographical location, social class, PC/TV time, physical activity, body mass index and waist circumference). CYP27B1 genotype was associated with both 25(OH)D (difference for A vs. C allele: 1.88%, 95% CI 0.37-3.4%, P = 0.01) and IgE concentrations ()6.59%, )11.6% to )1.42%, P = 0.01).

CONCLUSIONS

These data suggest that there may be a threshold effect with both low and high 25(OH)D levels associated with elevated IgE concentrations. The same CYP27B1 allele that is protective of diabetes was associated with increased IgE concentrations.

Vestibular dysfunction in vitamin D receptor mutant mice

The vitamin D endocrine system is essential for calcium and bone homeostasis. Vitamin D deficits are associated with muscle weakness and osteoporosis, whereas vitamin D supplementation may improve muscle function, body sway and frequency of falls, growth and mineral homeostasis of bones. The loss of muscle strength and mass, as well as deficits in bone formation, lead to poor balance. Poor balance is one of the main causes of falls, and may lead to dangerous injuries. Here we examine balance functions in vitamin D receptor deficient (VDR-/-) mice, an animal model of vitamin D-dependent rickets type II, and in 1alpha-hydroxylase deficient (1alpha-OHase-/-) mice, an animal model of pseudovitamin D-deficiency rickets. Recently developed methods (tilting box, rotating tube test), swim test, and modified accelerating rotarod protocol were used to examine whether the absence of functional VDR, or the lack of a key vitamin D-activating enzyme, could lead to mouse vestibular dysfunctions. Overall, VDR-/- mice, but not 1alpha-OHase-/- mice, showed shorter latency to fall from the rotarod, smaller fall angle in the tilting box test, and aberrant poor swimming. These data suggest that VDR deficiency in mice is associated with decreased balance function, and may be relevant to poorer balance/posture control in humans with low levels of vitamin D.

Vitamin D supplementation during Antarctic winter

BACKGROUND

Persons with limited exposure to ultraviolet B light, including space travelers, may not receive enough vitamin D. Recent studies indicate that optimal serum 25-hydroxyvitamin D [25(OH)D] should be > or = 80 nmol/L.

OBJECTIVE

This study was designed to evaluate the effectiveness of 3 doses of vitamin D to raise and maintain 25(OH)D to a concentration >80 nmol/L in persons with limited ultraviolet B light exposure.

DESIGN

This was a 5-mo, prospective, randomized, double-blind study of vitamin D supplementation. It was conducted during winter in Antarctica at the McMurdo Station, when ultraviolet B radiation levels are essentially zero. The 55 subjects were randomly divided into 3 groups for vitamin D supplementation: 2000 IU/d (n = 18), 1000 IU/d (n = 19), and 400 IU/d (n = 18). An additional 7 subjects did not take supplements or took supplements of their own choosing. Blood samples were collected about every 2 mo during the winter.

RESULTS

About 5 mo after supplementation started, 25(OH)D increased to 71 +/- 23 nmol/L in the 2000-IU/d group, 63 +/- 25 nmol/L in the 1000-IU/d group, and 57 +/- 15 nmol/L in the 400-IU/d group and decreased to 34 +/- 12 nmol/L in the group not taking supplements.

CONCLUSIONS

These data will enable us to provide space crews with evidence-based recommendations for vitamin D supplementation. The findings also have implications for other persons with limited ultraviolet light exposure, including polar workers and the elderly.

Vitamin D deficiency in older men

CONTEXT

Vitamin D deficiency is not adequately evaluated in older men.

OBJECTIVE

The aim of the study was to determine the prevalence of vitamin D deficiency and identify risk factors for its occurrence.

DESIGN AND SETTING

We conducted a cross-sectional evaluation of 1606 older men in the general community who were enrolled in the Osteoporotic Fractures in Men Study.

PARTICIPANTS

A randomly selected subcohort of a large population of men from six U.S. communities participated in the study.

MAIN OUTCOME MEASURES

Serum concentrations of 25-hydroxyvitamin D(2) [25(OH)D(2)] and 25(OH)D(3) were measured using mass spectrometry.

RESULTS

Deficiency [25(OH)D <20 ng/ml] was present in 26%, and insufficiency (<30 ng/ml) was present in 72%. Deficiency was particularly common among men during the winter and spring (especially in the northern communities) and in the oldest and more obese men. For instance, in Caucasian men in winter or spring who were >80 yr old, did not engage in lawn/garden work, and had a body mass index greater than 25 kg/m(2) and vitamin D intake below 400 IU/d, the prevalence of vitamin D deficiency was 86%. 25(OH)D(2) levels were present in a small fraction of men and accounted for a low proportion of total 25(OH)D levels. The use of vitamin D supplements was reported by 58% of men, but supplement use had a small effect on total 25(OH)D levels and, despite supplement use, low levels remained frequent.

CONCLUSIONS

Vitamin D deficiency is common in older men and is especially prevalent in obese, sedentary men living at higher latitudes. Use of vitamin D supplements at levels reported here did not result in adequate vitamin D nutrition.

Selective monitoring of vitamin D2 and D3 supplementation with a highly specific 25-hydroxyvitamin D3 immunoassay with negligible cross-reactivity to 25-hydroxyvitamin D2

BACKGROUND

The effects of vitamin D2 and D3 supplementation on circulating concentrations of 25(OH)D3 require reliable analytical tools for specific determination of 25(OH)D3 and 25(OH)D2. We have developed a highly specific 25-OH Vitamin D3 ELISA with negligible cross-reactivity towards 25(OH)D2.

METHODS

25(OH)D3 concentrations were measured in several study participants; 1) 641 healthy men and women; 2) 39 postmenopausal women receiving 400-800 IU vitamin D3 daily for 4 months; 3) 45 men and women with hip fracture receiving 1000 IU vitamin D2 daily for 3 months.

RESULTS

This 25-OH Vitamin D3 ELISA had minimal cross-reactivity to 25(OH)D2, (0.7%), and demonstrated a high correlation (r2 = 0.93) with 25(OH)D3 determined by HPLC. 25(OH)D3 increased by 14% in subjects receiving vitamin D3 for 4 months (p < 0.01), whereas there was no significant change in 25(OH)D3 levels in those receiving vitamin D2.

CONCLUSIONS

We report that 25(OH)D3 ELISA was used for evaluation of 25(OH)D3 concentrations in subjects receiving vitamin D2 and D3 supplementation. The increase of 25(OH)D3 in circulation with vitamin D3 supplementation and lack of increase with vitamin D2 supplementation suggest that this assay has sufficient sensitivity and specificity to be used as a reliable measurement of nutritional vitamin D3 status in humans.

Review article: vitamin D acquisition and breast cancer risk

OBJECTIVE

The aim of the study was to focus on the association of vitamin D and breast cancer.

METHODS

The study of evidence concerning vitamin D's influence on the origin and development of breast cancer from a PubMed and individual searches.

RESULTS

Body sunlight exposure may reduce the prevalence of breast cancer. However, these studies correspond to global populations of different countries and regions without considering other geographic factors and individual, ethnic, and cultural factors that may affect sunlight exposure. Epidemiological analyses show that low vitamin D ingestion is associated with increased risk of breast cancer. Studies measuring serum vitamin D metabolites in women who were followed many years suggest that low circulating 25-hydroxyvitamin D3 levels are associated with increased breast cancer risk.

CONCLUSIONS

Although there are controversial results, it seems plausible that sufficient endogenous vitamin D levels may have a protective function on mammary cells, reducing breast cancer risk.

Vitamin D and bone physiology: demonstration of vitamin D deficiency in an implant osseointegration rat model

PURPOSE

The patient population varies in nutritional deficiencies, which may confound the host response to biomaterials. The objective of this study was to evaluate the effect of a common deficiency of vitamin D on implant osseointegration in the rat model.

MATERIALS AND METHODS

Male Sprague-Dawley rats were maintained under the cessation of vitamin D intake and UV exposure. The serum levels of 1,25(OH)(2)D(3), 25 OHD(3), Ca, and P were determined. Miniature cylindrical Ti6Al4V implants (2-mm long, 1-mm diameter) were fabricated with double acid-etched (DAE) surface or modified DAE with discrete crystalline deposition (DCD) of hydroxyapatite nanoparticles. DAE and DCD implants were placed in the femurs of vitamin D-insufficient and control rats. After 14 days of healing, the femur-implant samples were subjected to implant push-in test and nondecalcified histology. The surfaces of recovered implant specimens after the push-in test were further evaluated by scanning electron microscopy (SEM).

RESULTS

The decreased serum level of 25 OHD(3) demonstrated the establishment of vitamin D insufficiency in this model. The implant push-in test revealed that DAE and DCD implants in the vitamin D-insufficient group (15.94 +/- 8.20 N, n = 7; 15.63 +/- 3.96 N, n = 7, respectively) were significantly lower than those of the control group (24.99 +/- 7.92 N, n = 7, p < 0.05; 37.48 +/- 17.58 N, n = 7, p < 0.01, respectively). The transcortical bone-to-implant contact ratio (BIC) was also significantly decreased in the vitamin D-insufficient group. SEM analyses further suggested that the calcified tissues remaining next to the implant surface after push-in test appeared unusually fragmented.

CONCLUSIONS

The effect of vitamin D insufficiency significantly impairing the establishment of Ti6Al4V implant osseointegration in vivo was unexpectedly profound. The outcome of Ti-based endosseous implants may be confounded by the increasing prevalence of vitamin D insufficiency in our patient population.

The use of vitamin D analogues in chronic kidney diseases: possible mechanisms beyond bone and mineral metabolism

Chronic kidney disease (CKD) is a common and costly medical condition, and currently available therapeutic options remain unsatisfactory. Vitamin D analogues are widely used for the bone and mineral disorder associated with CKD. However, accumulating evidence suggests that vitamin D analogues may have actions other than their effects on bone and mineral metabolism. In this article, we review the following aspects on the use of vitamin D analogues for the treatment of CKD: (1) epidemiological studies showing that patients with late-stage CKD have better survival than untreated patients; (2) animal studies showing that vitamin D analogues may retard the progression of CKD; (3) human studies on the anti-proteinuric and possibly renal protecting effects of vitamin D analogues in CKD and (4) the potential mechanisms of its therapeutic benefit. Nonetheless, definitive proof of the clinical benefits by randomized control trial would be necessary before one could advocate the routine use of vitamin D analogues for the treatment of CKD patients.

Myalgias or non-specific muscle pain in Arab or Indo-Pakistani patients may indicate vitamin D deficiency

The aim of our study was to determine the prevalence of vitamin D deficiency (<20 ng/dl) among patients with fibromyalgia or muscle pain in a musculoskeletal clinic in the United Arab Emirates. Consecutive patients who were diagnosed with fibromyalgia and/or non-specific musculoskeletal pain (ICD-9 729.1) were screened for vitamin D deficiency. Patients were seen at follow-up after treatment with vitamin D was given. Improvement was assessed by a simple questionnaire. Patients (139) with muscle pain were seen in 2007. Average age was 40 +/- year; 95% were female; 69 (49%) were Arab, of whom 92% were veiled; 43 (30%) Indian of whom 11% were veiled; 23 (16%) were Caucasian; and four were East Asian (3%) and all wore western clothes. One hundred three (74%) of these patients had a low vitamin D level. Vitamin D deficiency was most common among Arab patients (86%) and Indo-Pakistani (87%) and least common among the Caucasians (8%) and was equally prevalent among veiled and non-veiled patients. Treatment resulted in clinical improvement in 90% of patients. Non-specific muscle pains among Arab and Indian-Pakistani populations may indicate vitamin D deficiency, and prompt treatment can result in resolution of symptoms.

Ecological studies of ultraviolet B, vitamin D and cancer since 2000

PURPOSE

The purpose of this review is to summarize ecological studies of solar ultraviolet B (UVB), vitamin D and cancer since 2000.

METHODS

The journal literature is surveyed and summarized.

RESULTS

The ecological approach has been the primary tool used during the past two decades to extend the applicability of the UVB-vitamin D-cancer theory to include at least 18 types of cancer. Many of these studies were conducted in the United States, which has the advantages of availability of reliable age-standardized cancer incidence and mortality rate data for geographic areas at various spatial resolutions, and an asymmetric solar UVB dose pattern, with higher UVB irradiance in the west and lower in the east, at any particular latitude. In addition, indices for other cancer risk-modifying factors are readily available including those for smoking, alcohol consumption, ethnic background, urban/rural residence, socioeconomic status, air pollution, and in limited fashion, diet. The ecological approach has also been used to identify latitudinal variations in cancer mortality rates in Australia, China, Japan, and Spain, and in multicountry studies. It has been used to investigate the relative roles of solar UVB and dietary factors on a global scale. The ecological approach has also been applied to cancer survival. Studies in Norway and England found that individuals diagnosed with cancer in summer or fall, when serum 25-hydroxyvitamin D levels are highest, had a milder clinical course and longer survival than those diagnosed in winter or spring.

CONCLUSION

These findings provide strong evidence that vitamin D status plays an important role in controlling the outcome of cancer. Support for the UVB-vitamin D-cancer theory is now scientifically strong enough to warrant use of vitamin D in cancer prevention, and as a component of treatment. More research studies would help to explore whether there are benefits beyond the substantial effects that have been observed.

Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey

BACKGROUND

Recent studies suggest a role for vitamin D in innate immunity, including the prevention of respiratory tract infections (RTIs). We hypothesize that serum 25-hydroxyvitamin D (25[OH]D) levels are inversely associated with self-reported recent upper RTI (URTI).

METHODS

We performed a secondary analysis of the Third National Health and Nutrition Examination Survey, a probability survey of the US population conducted between 1988 and 1994. We examined the association between 25(OH)D level and recent URTI in 18 883 participants 12 years and older. The analysis adjusted for demographics and clinical factors (season, body mass index, smoking history, asthma, and chronic obstructive pulmonary disease).

RESULTS

The median serum 25(OH)D level was 29 ng/mL (to convert to nanomoles per liter, multiply by 2.496) (interquartile range, 21-37 ng/mL), and 19% (95% confidence interval [CI], 18%-20%) of participants reported a recent URTI. Recent URTI was reported by 24% of participants with 25(OH)D levels less than 10 ng/mL, by 20% with levels of 10 to less than 30 ng/mL, and by 17% with levels of 30 ng/mL or more (P < .001). Even after adjusting for demographic and clinical characteristics, lower 25(OH)D levels were independently associated with recent URTI (compared with 25[OH]D levels of > or =30 ng/mL: odds ratio [OR], 1.36; 95% CI, 1.01-1.84 for <10 ng/mL and 1.24; 1.07-1.43 for 10 to <30 ng/mL). The association between 25(OH)D level and URTI seemed to be stronger in individuals with asthma and chronic obstructive pulmonary disease (OR, 5.67 and 2.26, respectively).

CONCLUSIONS

Serum 25(OH)D levels are inversely associated with recent URTI. This association may be stronger in those with respiratory tract diseases. Randomized controlled trials are warranted to explore the effects of vitamin D supplementation on RTI.

Crohn's disease: the hot hypothesis

The peculiar geographic distribution of inflammatory bowel disease is a puzzle for researchers. A low vitamin D status has now been linked to several Th1-mediated autoimmune diseases, including multiple sclerosis, type 1 diabetes and rheumatoid arthritis, with the strongest evidence for the vitamin's protective role in multiple sclerosis. Sunlight and vitamin D may be potent immunomodulatory agents by down-regulating Th1-driven immune responses and inducing the synthesis of antimicrobial peptides considered as natural antibiotics of the immune system. Similarly to multiple sclerosis, we propose in CD the so-called north-south gradient may be partly explained by variations in the degree of sun exposure, with vitamin D being a "seasonal stimulus". These observations may yield a better understanding of the pathophysiology of Crohn's disease and pave the way for developing new therapeutic approaches for an incurable disease. Whether a low vitamin D status is associated with an increased risk of Crohn's disease in the general population and whether vitamin D and heliotherapy may be effective in treating Crohn's disease will require additional investigations.

Estimated benefit of increased vitamin D status in reducing the economic burden of disease in western Europe

Vitamin D has important benefits in reducing the risk of many conditions and diseases. Those diseases for which the benefits are well supported and that have large economic effects include many types of cancer, cardiovascular diseases, diabetes mellitus, several bacterial and viral infections, and autoimmune diseases such as multiple sclerosis. Europeans generally have low serum 25-hydroxyvitamin D [25(OH)D] levels owing to the high latitudes, largely indoor living, low natural dietary sources of vitamin D such as cold-water ocean fish, and lack of effective vitamin D fortification of food in most countries. Vitamin D dose-disease response relations were estimated from observational studies and randomized controlled trials. The reduction in direct plus indirect economic burden of disease was based on increasing the mean serum 25(OH)D level to 40 ng/mL, which could be achieved by a daily intake of 2000-3000 IU of vitamin D. For 2007, the reduction is estimated at euro187,000 million/year. The estimated cost of 2000-3000 IU of vitamin D3/day along with ancillary costs such as education and testing might be about euro10,000 million/year. Sources of vitamin D could include a combination of food fortification, supplements, and natural and artificial UVB irradiation, if properly acquired. Additional randomized controlled trials are warranted to evaluate the benefits and risks of vitamin D supplementation. However, steps to increase serum 25(OH)D levels can be implemented now based on what is already known.

Vitamin D and the vasculature: can we teach an old drug new tricks?

BACKGROUND

Vitamin D is a steroid hormone known for its role in regulating levels of calcium and phosphorus. Vitamin D has important autocrine/paracrine roles and it is involved in vascular biology. Clinical studies have shown a relationship between vitamin D levels and cardiovascular health, and low levels of vitamin D metabolites have been associated with higher incidence of congestive heart failure and increases in mortality.

OBJECTIVE

To summarise the effect of vitamin D on cardiovascular pathology, the leading cause of death in chronic kidney disease patients.

CONCLUSIONS

All results indicate a potential effect of vitamin D on cardiovascular health. Therefore, maintaining optimum levels of circulating vitamin D is critical for a healthy cardiovascular system. In patients with low vitamin D status, like renal patients, supplementation with vitamin D metabolites has shown beneficial cardiovascular effects.

The efficacy and safety of calcitriol and/or Caltrate D in elderly Chinese women with low bone mass

AIM

To observe the efficacy and safety of Rocaltrol (calcitriol) and/or Caltrate D (calicum carbonate plus vitamin D) in elderly Chinese women with osteopenia or osteoporosis.

METHODS

One hundred fifty Chinese women aged over 65 years with osteopenia or osteoporosis from three centers were randomly divided into two groups. Seventy-six participants received Caltrate D as one pill daily; the other 74 participants received 0.25 mug Caltrate D plus Rocaltrol daily. The changes in bone mineral density (BMD) served as primary end-points. Height changes, the presence of new vertebral fractures, muscle strength and balance were evaluated.

RESULTS

The following are the mean percentage changes (and SD) in BMD over 12 months: at L2-L4, 0.83+/-3.88 in the Caltrate D group and 2.84+/-4.04 in the Rocaltrol+Caltrate D group (P=0.003, by ANCOVA); at the femoral neck, 0.04+/-3.94 in the Caltrate D group and 2.01+/-5.45 in the Rocaltrol+Caltrate D group (P=0.085, by ANCOVA); and in the trochanter, 1.59+/-4.57 in the Caltrate D group and 3.76+/-6.25 in the Rocaltrol+Caltrate D group (P=0.053, by ANCOVA). The stand and maximal forward reach test (SMFRT) was significantly enhanced in both groups during the 12 months of treatment, but no significant differences were found between these two groups. No severe adverse event related to these medications occurred throughout the study.

CONCLUSION

Treatment with Rocaltrol plus Caltrate D or Caltrate D for 12 months in elderly Chinese postmenopausal women effectively increased BMD at the lumbar spine. Rocaltrol plus Caltrate D was more effective at the lumbar spine than Caltrate D alone.

Patients with Gaucher disease living in England show a high prevalence of vitamin D insufficiency with correlation to osteodensitometry

AIM

Gaucher disease type 1 (GD-1) is the most prevalent lysosomal storage disorder and frequently causes osteopenia and osteoporosis. Adequate vitamin D levels are essential for bone health. The present study retrospectively analyzed 25-hydroxyvitamin D (25[OH]D) in outpatients with GD-1.

PATIENTS AND METHODS

Sixty GD-1 patients living at home and with residence in southern or central England (34 men, 26 women), aged 17-85 years (mean 45.0 years) were seen at routine follow-up visits (range: 1-9, mean: 4.4) between January 2003 and July 2007. Overall, 264 blood samples, collected at different seasons of the year, were present for laboratory testing. The retrospective interpretation of vitamin D deficiency was based on different cut-off levels of 25(OH)D (<25 nmol/L, <50 nmol/L, <80 nmol/L) and the seasons of the year. Vitamin D sufficiency was defined as 25(OH)D >80 nmol/L.

RESULTS

The mean+/-SD of 25(OH)D was 58.2+/-30.3. Degrees of vitamin D deficiency (<25 nmol/L, <50 nmol/L, <80 nmol/L) were present in 9.1%, 44.3%, 83.0%, vitamin D sufficiency (>80 nmol/L) in only 17.0%, respectively. A significant seasonal variation of 25(OH)D was present. Results of vitamin D deficiency for December-May were 15.7%, 63.8%, 92.9%, and for June-November 2.9%, 26.3%, 73.7%. The 25(OH)D values representing the seasonal nadir observed during the season December-May showed a significant correlation with T-scores and Z-scores of the lumbar spine and hip. Parathyroid hormone and 25(OH)D were inversely correlated.

CONCLUSIONS

Vitamin D deficiency is frequent among GD-1 patients. To optimize treatment of GD-1 vitamin D supplementation should be recommended.

Menthol Enhances an Antiproliferative Activity of 1alpha,25-Dihydroxyvitamin D(3) in LNCaP Cells

1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], the most active form of vitamin D(3), and its analogues have therapeutic benefits for prostate cancer treatment. However, the development of hypercalcemia is an obstacle to clinical applications of 1alpha,25(OH)(2)D(3) for cancer therapy. In this study, we provide evidence that menthol, a key component of peppermint oil, increases an anti-proliferation activity of 1alpha,25(OH)(2)D(3) in LNCaP prostate cancer cells. We found that menthol per se does not exhibit antiproliferative activity, but it is able to enhance 1alpha,25(OH)(2)D(3)-mediated growth inhibition in LNCaP cells. Fluorometric assays using Fura-2 showed that 1alpha,25(OH)(2)D(3) does not induce acute Ca(2+) response, whereas menthol evokes an increase in [Ca(2+)](i), which suggests that cross-talks of menthol-induced Ca(2+) signaling with 1alpha,25(OH)(2)D(3)-mediated growth inhibition pathways. In addition, Western blot analysis revealed that 1alpha,25(OH)(2)D(3) and menthol cooperatively modulate the expression of bcl-2 and p21 which provides the insight into the molecular mechanisms underlying the enhanced 1alpha,25(OH)(2)D(3)-mediated growth inhibition by menthol. Thus, our findings suggest that menthol may be a useful natural compound to enhance therapeutic effects of 1alpha,25(OH)(2)D(3).

Treatment of osteoporosis with parathyroid hormone and teriparatide

Nowadays osteoporosis treatment is based primarily on therapy with antiresorptive agents, like the bisphosphonates. Parathyroid hormone (Preotact) and human recombinant parathyroid hormone peptide 1-34 (Teriparatide) are relatively new for the treatment of osteoporosis and belong to the group of anabolic agents. Both agents demonstrated an increase in bone mineral density and a significant reduction in vertebral fractures in postmenopausal women with osteoporosis when given for 18-24 months. Data on nonvertebral fractures are, however, not clear-cut, and so far only bisphosphonates and strontium ranelate have been demonstrated to reduce all types of fractures and therefore remain the front-line option for treatment of osteoporosis. As the safety, tolerability, and cost of the therapy also influence the choice of therapy, Preotact and Teriparatide might be useful additions to the armamentarium for (second-line) treatment of osteoporosis.

Erythropoietin dosing in children with chronic kidney disease: based on body size or on hemoglobin deficit?

There are no investigations demonstrating that body size-adapted doses of erythropoietin (EPO) are as equally effective in children as in adults. A treatment starting with 150 IU/kg body weight per week leads to an insufficient rise in hemoglobin levels in anemic children with chronic kidney disease (CKD). Nevertheless, this strategy is widely used and seems to be the reason for a high percentage of young anemic children in spite of EPO treatment. In children and in adults, 1,000 IU EPO intravenously increases the hemoglobin level equally by 0.04 g/l. This strongly argues for specifying the EPO dose in the treatment of children with CKD in absolute amounts. A prediction model exists which allows the determination of the EPO dose which is expected to raise hemoglobin from a given pretreatment level to a desired steady state level.