Vitamin D status and health correlates among German adults

Protective role of the vitamin D receptor

Vitamin D receptor (VDR) is found in most tissues, not just those participating in the classic actions of vitamin D such as bone, gut, and kidney. The nonclassic actions are therefore potential targets for the active metabolite of vitamin D, 1,25(OH)₂D₃. This review is intended to highlight the actions of VDR in role of protection. Medline is searched for articles describing actions of VDR on secondary hyperparathyroidism, diabetic nephropathy, hypertension and atherosclerosis. VDR exerts its protective activities through the following mechanisms: inhibition of renin-angiotensin system (RAS); regulation of proliferation and differentiation; reduction of proteinuria; anti-inflammation and anti-fibrosis. The nonclassic actions of VDR provide a number of potential new clinical applications for 1,25(OH)₂D₃ and its analogs. We believe 1,25(OH)₂D₃/VDR can be of particular value in the prevention of kidney-related diseases.

Vitamin D: The "sunshine" vitamin

Vitamin D insufficiency affects almost 50% of the population worldwide. An estimated 1 billion people worldwide, across all ethnicities and age groups, have a vitamin D deficiency (VDD). This pandemic of hypovitaminosis D can mainly be attributed to lifestyle (for example, reduced outdoor activities) and environmental (for example, air pollution) factors that reduce exposure to sunlight, which is required for ultraviolet-B (UVB)-induced vitamin D production in the skin. High prevalence of vitamin D insufficiency is a particularly important public health issue because hypovitaminosis D is an independent risk factor for total mortality in the general population. Current studies suggest that we may need more vitamin D than presently recommended to prevent chronic disease. As the number of people with VDD continues to increase, the importance of this hormone in overall health and the prevention of chronic diseases are at the forefront of research. VDD is very common in all age groups. As few foods contain vitamin D, guidelines recommended supplementation at suggested daily intake and tolerable upper limit levels. It is also suggested to measure the serum 25-hydroxyvitamin D level as the initial diagnostic test in patients at risk for deficiency. Treatment with either vitamin D2 or vitamin D3 is recommended for deficient patients. A meta-analysis published in 2007 showed that vitamin D supplementation was associated with significantly reduced mortality. In this review, we will summarize the mechanisms that are presumed to underlie the relationship between vitamin D and understand its biology and clinical implications.

Vitamin D-insufficiency: An estimate of the situation in Germany

Background: Vitamin D insufficiency is increasingly recognized as an important risk factor in the pathogenesis of falls and fractures and may increase the risk of other diseases. The aim of this study was to obtain information about the vitamin D supply from a representative cohort of the German population.

 

Methods: 264 General practitioners participated in the DeViD-Trial (D-Vitamin in Deutschland) by taking blood samples from their consenting daily ambulant patients regardless of the actual reason for consultation. In these blood samples vitamin D [25(OH)D] and other related parameters were measured at a central laboratory. The patients filled in a simple questionnaire (i.e., age, sex, etc.). The trial was performed between February 26 and May 25, 2007.

Results: Laboratory and personal data were documented for 1,343 individuals (615 men, 728 women). The age distribution ranged from 20 to 99 y, the mean age of the whole cohort was 57.6 y (men 58.2, women 57.2). The mean 25-OH-D-value for the whole cohort was 16.2 ng/ml (range: 6.0 to 66.8, median 14.1 ng/ml). Ten percent of the patients had 25(OH)D-values below 7 ng/ml, 65% below 20 ng/ml and 92% showed values below 30 ng/ml.

In the more recent literature, 25(OH)D values below 30 ng/ml are regarded as sub-optimal for bone, muscle and general health. Correspondingly it can be stated that in this representative population there is a high prevalence of moderate to severe vitamin D-insufficiency regardless of young or old age

Public health implications of standardized 25-hydroxyvitamin D levels: a decrease in the prevalence of vitamin D deficiency among older women in Germany

OBJECTIVE

To compare the public health implications of using unstandardized immunoassay measurements of serum 25-hydroxyvitamin D [25(OH)D] concentrations versus using measurements standardized by liquid chromatography tandem-mass spectrometry (LC-MS/MS) when assessing the prevalence of 25(OH)D insufficiency and deficiency in various subgroups of individuals.

METHOD

We standardized immunoassay-based measurements of 25(OH)D with LC-MS/MS in a population-based sample of 5386 women aged 50-74 recruited in 2000-2002 in Germany. We used multivariate regression to assess 25(OH)D determinants and the association of vitamin D deficiency with health status.

RESULTS

Prevalences of 25(OH)D levels <50 nmol/L (insufficiency) and <30 nmol/L (deficiency) decreased considerably by standardization. The decrease in vitamin D deficiency (from 64.4% to 17.9%) was particularly strong in March-May among women aged ≥ 65. Independent of season of blood draw and standardization, women ≥ 70 years, obese, or currently smoking had an increased risk of having 25(OH)D levels <30 nmol/L.

CONCLUSION

The proportion of older women with vitamin D deficiency in Germany is much lower than previously reported, but prevalence of vitamin D insufficiency is high. Standardization of 25(OH)D values by immunoassay methods to LC-MS/MS equivalent values or direct measurement by LC-MS/MS is indispensable in drawing valid conclusions about the health implications of vitamin D deficiency or insufficiency.

A global representation of vitamin D status in healthy populations

PURPOSE

This paper visualizes the available data on vitamin D status on a global map, examines the existing heterogeneities in vitamin D status and identifies research gaps.

METHODS

A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011. Studies were eligible if they included samples of randomly selected males and females from the general population and assessed circulating 25-hydroxyvitamin D [25(OH)D] levels. Two different age categories were selected: children and adolescents (1-18 years) and adults (>18 years). Studies were chosen to represent a country based on a hierarchical set of criteria.

RESULTS

In total, 200 studies from 46 countries met the inclusion criteria, most coming from Europe. Forty-two of these studies (21 %) were classified as representative. In children, gaps in data were identified in large parts of Africa, Central and South America, Europe, and most of the Asia/Pacific region. In adults, there was lack of information in Central America, much of South America and Africa. Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L.

CONCLUSIONS

This study provides an overview of 25(OH)D levels around the globe. It reveals large gaps in information in children and adolescents and smaller but important gaps in adults. In view of the importance of vitamin D to musculoskeletal growth, development, and preservation, and of its potential importance in other tissues, we strongly encourage new research to clearly define 25(OH)D status around the world.

High prevalence of vitamin D deficiency in pregnant women: a national cross-sectional survey

An increasing number of studies suggest that vitamin D deficiency during pregnancy is associated with multiple adverse health outcomes in mothers, neonates and children. There are no representative country data available on vitamin D status of pregnant women in Europe. The aim of this study was to estimate the prevalence of vitamin D deficiency among Belgian pregnant women and to assess the determinants of vitamin D status in the first and third trimester of pregnancy. The women were selected via a multi-stage proportionate-to-size sampling design. Blood samples were collected and a questionnaire was completed face-to-face. 55 obstetric clinics were randomly selected and 1311 pregnant women participated in the study. The median serum 25-hydroxyvitamin D [25-(OH)D] concentration was significantly lower in the first trimester (20.4 ng/ml) than in third trimester (22.7 ng/ml). Of all women, 74.1% (95%CI = 71.8–76.5%) were vitamin D insufficient (25-(OH)D <30 ng/ml), 44.6% (95%CI = 41.9–47.3%) were vitamin D deficient (25-(OH)D <20 ng/ml), while 12.1% (95%CI = 10.3–13.8%) were severely vitamin D deficient (25-(OH)D <10 ng/ml). Of all women included, 62.0% reported taking vitamin D-containing multivitamins, of which only 24.2% started taking those before pregnancy. The risk of vitamin D deficiency (25-(OH)D <20 ng/ml) was significantly higher for less educated women and women who reported not going on holidays to sunny climates. The risk of severe vitamin D deficiency (25-(OH)D <10 ng/ml) decreased for women who reported alcohol consumption during pregnancy, decreased with more frequent use of sunscreen lotion and increased for smokers and women who reported preference for shadow. In conclusion, vitamin D deficiency is highly prevalent among pregnant women in Belgium and this raises concerns about the health consequences for the mother and the offspring. A targeted screening strategy to detect and treat women at high risk of severe vitamin D deficiency is needed in Belgium and in Europe.

Vitamin D status indicators in indigenous populations in East Africa

PURPOSE

Sufficient vitamin D status may be defined as the evolutionary established circulating 25-hydroxyvitamin D [25(OH)D] matching our Paleolithic genome.

METHODS

We studied serum 25(OH)D [defined as 25(OH)D₂ + 25(OH)D₃] and its determinants in 5 East African ethnical groups across the life cycle: Maasai (MA) and Hadzabe (HA) with traditional life styles and low fish intakes, and people from Same (SA; intermediate fish), Sengerema (SE; high fish), and Ukerewe (UK; high fish). Samples derived from non-pregnant adults (MA, HA, SE), pregnant women (MA, SA, SE), mother-infant couples at delivery (UK), infants at delivery and their lactating mothers at 3 days (MA, SA, SE), and lactating mothers at 3 months postpartum (SA, SE). Erythrocyte docosahexaenoic acid (RBC-DHA) was determined as a proxy for fish intake.

RESULTS

The mean ± SD 25(OH)D of non-pregnant adults and cord serum were 106.8 ± 28.4 and 79.9 ± 26.4 nmol/L, respectively. Pregnancy, delivery, ethnicity (which we used as a proxy for sunlight exposure), RBC-DHA, and age were the determinants of 25(OH)D. 25(OH)D increased slightly with age. RBC-DHA was positively related to 25(OH)D, notably 25(OH)D₂. Pregnant MA (147.7 vs. 118.3) and SE (141.9 vs. 89.0) had higher 25(OH)D than non-pregnant counterparts (MA, SE). Infant 25(OH)D at delivery in Ukerewe was about 65 % of maternal 25(OH)D.

CONCLUSIONS

Our ancient 25(OH)D amounted to about 115 nmol/L and sunlight exposure, rather than fish intake, was the principal determinant. The fetoplacental unit was exposed to high 25(OH)D, possibly by maternal vitamin D mobilization from adipose tissue, reduced insulin sensitivity, trapping by vitamin D-binding protein, diminished deactivation, or some combination.

Vitamin D and vascular disease: the current and future status of vitamin D therapy in hypertension and kidney disease

Over the past decade, vitamin D has generated considerable interest as potentially having important effects on the vasculature and the kidney. Animal and human data indicate that vitamin D suppresses the activity of the renin-angiotensin system and improves endothelial function. Observational studies in humans suggest that low 25-hydroxyvitamin D (25[OH]D) levels are associated with a higher risk of hypertension. However, findings from randomized trials of vitamin D supplementation (with cholecalciferol or ergocalciferol) to lower blood pressure are inconsistent, possibly stemming from variability in study population, sample size, vitamin D dose, and duration. Supplementation with activated vitamin D (i.e., 1,25-dihydroxyvitamin D or analogues) in patients with chronic kidney disease reduces urine albumin excretion, an important biomarker for future decline in renal function. These studies are reviewed, with special emphasis on recent findings. Definitive studies are warranted to elucidate the effects of vitamin D supplementation on mechanisms of hypertension and kidney disease.

Depression is associated with low levels of 25-hydroxyvitamin D among Jordanian adults: results from a national population survey

Although low serum 25-hydroxyvitamin D (25(OH)D) and elevated serum parathyroid hormone (PTH) have been associated with depression in clinical settings, this link in community-dwelling individuals is inconclusive. The present study aimed at examining the association between serum 25(OH)D and PTH levels and the presence of depression in a national population-based household sample of 4,002 Jordanian participants aged ≥25 years. The DASS21 depression scale was used to screen for depression, and serum concentrations of 25(OH)D and PTH were measured by radioimmunoassay. Multiple logistic regression models were used to explore the association between serum 25(OH)D and PTH levels and depression. The unadjusted odds ratio (OR) decreased linearly with increasing quartiles of serum 25(OH)D (P(trend) = 0.00). The OR for having depression was significantly higher among individuals in the first and second quartiles (OR = 1.4, 1.23, respectively) than among those in the fourth quartile (P values = 0.00 and 0.03, respectively). This relationship remained significant after adjusting for age, sex, marital status, education, BMI, serum creatinine, number of chronic diseases (OR = 1.39 and 1.21 and P values = 0.00 and 0.05, respectively) and after further adjustment for exercise, altitude, and smoking (OR = 1.48 and 1.24, respectively, and P values = 0.00 and 0.03, respectively). No significant association was found between serum PTH levels and depression. The decrease in risk of depression among participants started to be significant with serum 25(OH) D levels higher than 42.3 ng/ml (lower limit of the range of the third quartile). This value may help pinpoint the desirable level of serum 25(OH)D to be attained to help aid the prevention and treatment of depression.

Serum 25-hydroxyvitamin D3 and body composition in an elderly cohort from Germany: a cross-sectional study

Background

Emerging evidence indicates that there is an association between vitamin D and obesity. The aim of this study was to investigate whether the level of serum 25-hydroxyvitamin D₃ [25(OH)D₃] in the elderly is influenced by parameters of anthropometry and body composition independent of potential confounding lifestyle factors and the level of serum intact parathyroid hormone (iPTH).

Methods

Cross-sectional data of 131 independently living participants (90 women, 41 men; aged 66–96 years) of the longitudinal study on nutrition and health status in senior citizens of Giessen, Germany were analysed. Concentrations of 25(OH)D₃ and iPTH were ascertained by an electrochemiluminescence immunoassay. Body composition was measured by a bioelectrical impedance analysis. We performed univariate and multiple regression analyses to examine the influence of body composition on 25(OH)D₃ with adjustments for age, iPTH and lifestyle factors.

Results

In univariate regression analyses, 25(OH)D₃ was associated with body mass index (BMI), hip circumference and total body fat (TBF) in women, but not in men. Using multiple regression analyses, TBF was shown to be a negative predictor of 25(OH)D₃ levels in women even after controlling for age, lifestyle and iPTH (ß = −0.247; P = 0.016), whereas the associations between BMI, hip circumference and 25(OH)D₃ lost statistical significance after adjusting for iPTH. In men, 25(OH)D₃ was not affected by anthropometric or body composition variables.

Conclusions

The results indicate that 25(OH)D₃ levels are affected by TBF, especially in elderly women, independent of lifestyle factors and iPTH.

ApoE genotype: from geographic distribution to function and responsiveness to dietary factors

ApoE is a key protein in lipid metabolism with three major isoforms.ApoEallele frequencies show non-random global distribution especially in Europe with highapoEε3frequency in the Mediterranean area, whereas theapoEε4genotype is enriched in Northern Europe. TheapoEε4genotype is one of the most important genetic risk factors for age-dependent chronic diseases, including CVD and Alzheimer's disease (AD). The apoE polymorphism has been shown to impact on blood lipids, biomarkers of oxidative stress and chronic inflammation, which all may contribute to the isoform-dependent disease risk. Studies in mice and human subjects indicate that theapoEε3but not theapoEε4genotype may significantly benefit from dietary flavonoids (e.g. quercetin) andn-3 fatty acids. Metabolism of lipid soluble vitamins E and D is likewise differentially affected by theapoEgenotype. Epidemiological and experimental evidence suggest a better vitamin D status inapoEε4than ε3subjects indicating a certain advantage of ε4over ε3. The present review aims at evaluation of current data available on interactions between apoE polymorphism and dietary responsiveness to flavonoids, fat soluble vitamins andn-3 fatty acids. Likewise, distinct geographic distribution and chronic disease risk of the different apoE isoforms are addressed.

Association between vitamin D status and metabolic syndrome risk among Korean population: based on the Korean National Health and Nutrition Examination Survey IV-2, 2008

AIMS

Low serum 25-hydroxyvitamin D (25(OH)D) levels have been linked to metabolic syndrome. However, community-based data for healthy Korean individuals are lacking. We aimed to assess the vitamin D status and the association of 25(OH)D deficiency with metabolic syndrome in the South Korean population (latitude 33-38°N).

METHODS

In this population-based study, we assessed 5559 South Korean adults selected from the Korean National Health and Nutrition Examination Survey IV-2, 2008. We used multiple logistic regression analysis to assess the association between vitamin D deficiency and metabolic syndrome.

RESULTS

The prevalence of vitamin D deficiency (<20 ng/mL) was 56.0%. Subjects with vitamin D deficiency were younger and had higher education, lower physical activity, and lower alcohol consumption than those with normal vitamin D levels. The overall risk of metabolic syndrome was not associated with 25(OH)D concentration. The adjusted OR of reduced high density lipoprotein cholesterol (HDL-C) decreased across the quintiles of 25(OH)D concentrations (OR=0.72; 95% confidence interval=0.54-0.95 for comparisons of lowest vs. highest quintile; P for trend=0.003).

CONCLUSIONS

A high prevalence of vitamin D deficiency was noted in the general South Korean population. Serum 25(OH)D concentration was inversely associated with the risk of having reduced HDL-C.

The relationship between vitamin D and the renin-angiotensin system in the pathophysiology of hypertension, kidney disease, and diabetes

Vitamin D has been implicated in the pathophysiology of extraskeletal conditions such as hypertension, kidney disease, and diabetes via its ability to negatively regulate the renin-angiotensin system (RAS). This article reviews the evidence supporting a link between vitamin D and the RAS in these conditions, with specific emphasis on translational observations and their limitations. A literature review of animal and human studies evaluating the role of vitamin D in hypertension, kidney disease, and diabetes was performed. Excess activity of the RAS has been implicated in the pathogenesis of hypertension, chronic kidney disease, decreased insulin secretion, and insulin resistance. Animal studies provide strong support for 1,25-dihydroxyvitamin D(3)-mediated downregulation of renin expression and RAS activity via its interaction with the vitamin D receptor. Furthermore, the activity of vitamin D metabolites in animals is associated with reductions in blood pressure, proteinuria and renal injury, and with improved β-cell function. Many observational, and a few interventional, studies in humans have supported these findings; however, there is a lack of well-designed prospective human interventional studies to definitively assess clinical outcomes. There is a need for more well-designed prospective interventional studies to validate this hypothesis in human clinical outcomes.

Determinants of vitamin D status in a general population of Danish adults

BACKGROUND AND AIMS

Danish legislation regarding food fortification has been very restrictive and vitamin D deficiency is thought to be common in Denmark due to inadequate dietary intakes and the fact that in Denmark (latitude 56°N) vitamin D is only synthesized in the skin after exposure to solar radiation during summertime (April-September). The purpose of this study was to evaluate the vitamin D status of a general adult population in Denmark and, in addition, associations between vitamin D status and distinct lifestyle factors were studied.

METHODS

A random sample of 6784 persons from a general population aged 30-60 years participated in a health examination in 1999-2001. Serum samples from all participants were stored and levels of 25-hydroxyvitamin D (25(OH)D) were measured by HPLC in 2009. The method was compared to another HPLC method. Information on dietary intake of vitamin D and other lifestyle factors were obtained by questionnaires. A total of 6146 persons defined as ethnic Danes and with successful measurements of 25(OH)D were included in the analyses.

RESULTS

The overall prevalence of vitamin D deficiency (25(OH)D<25 nmol/l) and insufficiency (25(OH)D<50 nmol/l) were 13.8% and 52.2%, respectively. A marked seasonal fluctuation was seen in serum levels of 25(OH)D - median values of 25(OH)D were lowest in February and highest in August. In multiple logistic regression models (n=5506), low vitamin D status was significantly associated with obesity (BMI≥30), daily smoking and a sedentary lifestyle. However, measurements of 25(OH)D were not associated with the estimated dietary intake of vitamin D. Comparison of two HPLC methods demonstrated considerable differences in accuracy.

DISCUSSION AND CONCLUSIONS

Our results suggest that poor vitamin D status is common among adults in a Northern European country without food fortification with vitamin D. Methodological issues are, however, of great importance when using cut-off values to define poor vitamin D status. In addition, we demonstrated that low serum levels of 25(OH)D were associated with several lifestyle factors.

Epidemic vitamin D deficiency among patients in an elderly care rehabilitation facility

BACKGROUND

Many benefits are ascribed to vitamin D beyond its well-known effects on calcium and bone metabolism. Vitamin D in adequate amounts is apparently beneficial to muscle, lessening the risk of falls and fractures in the elderly. The elderly produce less vitamin D in their skin than younger persons do, and they also spend less time in the sun; they are therefore at greater risk of vitamin D deficiency.

METHODS

We used gas chromatography with mass spectrometry coupling to measure the 25-OH-vitamin D level of 1578 elderly persons (72% women) who were consecutively admitted to an elderly care rehabilitation facility in Trier, Germany, from July 2009 to March 2011. Their mean and median age was 82 years.

RESULTS

89% of the patients had 25-OH-vitamin D deficiency (defined as a level below 20 ng/mL), and 67% had a severe deficiency (below 10 ng/mL). Only 4% had levels in the target range (30-60 ng/mL); none had a level above 100 ng/mL.

CONCLUSION

Many of these patients were deficient in vitamin D. Persons of very advanced age need a better supply of vitamin D not only to keep their bones healthy, but also to lessen the risk of falls and fractures.

Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies

BACKGROUND

Low vitamin D status may increase mortality risk.

OBJECTIVE

We used nonparametric ("highest compared with lowest" categories) and parametric (>2 categories) statistical models to evaluate associations of 25-hydroxyvitamin D [25(OH)D] serum concentrations and mortality in observational studies among general populations.

DESIGN

We searched PubMed, EMBASE, Web of Science, and reference lists for relevant articles. We included studies that contained data on relative risks (RRs) for mortality for different 25(OH)D concentrations, which included a corresponding measure of uncertainty, and this yielded 14 prospective cohort studies that involved 5562 deaths out of 62,548 individuals. We applied log-transformed RRs and CIs, adjusted for the maximal number of confounding variables. In the parametric model, which is based on 11 studies and 59,231 individuals, we used the lowest quantile as the reference category.

RESULTS

For "highest compared with lowest" categories of 25(OH)D, the estimated summary RR of mortality was 0.71 (95% CI: 0.50, 0.91). In the parametric model, the estimated summary RRs (95% CI) of mortality were 0.86 (0.82, 0.91), 0.77 (0.70, 0.84), and 0.69 (0.60, 0.78) for individuals with an increase of 12.5, 25, and 50 nmol 25(OH)D serum values/L, respectively, from a median reference category of ∼27.5 nmol/L. There was, however, no significant decrease in mortality when an increase of ∼87.5 nmol/L above the reference category occurred.

CONCLUSION

Data suggest a nonlinear decrease in mortality risk as circulating 25(OH)D increases, with optimal concentrations ∼75-87.5 nmol/L.

Serum vitamin D concentration status and its correlation with early biomarkers of remodeling following acute myocardial infarction

BACKGROUND

Low serum level of vitamin D was shown to be associated with cardiovascular diseases as well as the presence of diabetes, dyslipidemia, and hypertension. Vitamin D deficiency is a global problem, and is an Iranian problem as well. To the best of our knowledge, this was the first study on acute myocardial infarction that evaluates the correlation of vitamin D level with inpatients' outcomes, particularly on the early biomarkers of myocardial remodeling.

METHODS

In a prospective study, patients with acute ST segment elevation myocardial infarction were included. The patients' 25 (OH) D levels were identified and the associations with clinical characteristics, including early remodeling biomarkers and in-hospital outcomes, were investigated.

RESULTS

From the 139 included patients, 80.5% were male. The 25 (OH) deficiency was present in 72.7% of the patients. Hypertension and positive history of cardiovascular drug use were risk factors for the presence of low vitamin D levels (OR = 2.92; CI = 1.34-6.37, P < 0.05) and (OR = 2.36; CI = 1.05-5.29, P < 0.05), respectively. Moreover, a significant positive relationship between the inpatients' survival and the concentration of vitamin D was present (P < 0.001). By performing a multivariate analysis, we found that there was a significant inverse relationship between the level of 25 (OH) D and the level of MMP-9 after 72 h (P = 0.011).

CONCLUSION

The results of our study revealed a significant inverse relationship between serum MMP-9 as a biomarker of early remodeling and the level of 25(OH) D in patients after an acute myocardial infarction. Moreover, low level of vitamin D was associated with patients' mortality in this study.

Seasonal variation of serum 25-hydroxyvitamin D levels in adult patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are at risk of osteoporosis. Vitamin D (vitD) deficiency is known as a risk factor of osteoporosis. We observed low vitD blood levels in adult IBD patients both at the end of summer and winter. Furthermore, effects of oral vitD supplementation in (generally low) daily dosages were poor.

INTRODUCTION

Patients with IBD are at risk of osteoporosis. This study evaluates seasonal vitD status, determinants of vitD deficiency and effects of vitD supplementation in adult IBD patients.

METHODS

Patients were screened for vitD deficiency at the end of summer and winter using serum 25OHD(3) (cut-off point, <50 nmol/L) combined with routine laboratory tests. A standardized questionnaire was used for demographic/lifestyle data i.e. IBD activity, health behaviour and vitD intake through diet and ultraviolet light.

RESULTS

Late-summer, 39% of the included 316 patients were vitD deficient. Late-winter, 57% of the follow-up patients (n=281) were deficient. Independent protective determinants of vitD deficiency were oral vitD supplementation (summer/winter: odds ratio [OR], 0.52 [95% confidence interval [CI], 0.29-0.94]/OR, 0.44 [95% CI, 0.26-0.75]), recent sun holiday (summer: OR, 0.42 [95% CI, 0.24-0.74]) and regular solarium visits (summer/winter: OR, 0.28 [95% CI, 0.13-0.63]/OR, 0.17 [0.06-0.50]). IBD activity (p=0.031), red blood cell distribution width (RDW; p=0.04) and erythrocyte sedimentation rate (p=0.03) were associated with low vitD levels using univariate analyses of the extreme 25OHD quartiles. In a subgroup with vitD supplementation, still 30% (late-summer) and 44% (late-winter) were vitD deficient.

CONCLUSION

VitD deficiency is common in IBD patients, but prevalence might be comparable with the general population. Ultraviolet light is essential for adequate vitD levels. Effects of oral vitD supplementation in (generally low) daily dosages are poor. Determinants for low vitD levels were IBD activity and elevated inflammatory markers, suggesting that increased risk of osteoporosis in IBD might be more related to the inflammation than to vitD deficiency.

[Dietary efficacy of a micronutrient combination in patients with recurrent upper respiratory tract infections. Results of a placebo-controlled doubleblind study.]

BACKGROUND AND OBJECTIVES

An optimal vitamin and mineral supply may contribute to the enhancement of immune defenses and thus favorably influence the course and intensity of recurrent upper respiratory tract infections (URIs). In the present study the dietary efficacy and benefits of a micronutrient combination in patients with recurrent URIs was evaluated.

METHODS

192 patients with recurrent URIs were enrolled in this randomized, placebo-controlled, double-blind multicenter trial for a study duration of 16 weeks. Efficacy variables were number, intensity and course of URIs (as assessed using a total common cold score [CCS]) and the alterations in micronutrient supply (vitamins C and D3, folic acid and selenium) during the study.

RESULTS

In subjects who initially had at least two common cold symptoms (N = 107) the symptoms improved in the active group (AG) significantly more than in the placebo group (PG; ΔCCS: AG -6.9 ± 4.8; PG -5.4 ± 4.5; p = 0.034). In patients with initially severe common cold (CC) episodes the symptoms improved in the AG to a statistically significant extent (ΔCCS: AG -93.8%, PG -91.2%, p = 0.043). In the age group below 45 years significantly fewer AG than PG patients were absent from their job during the second or third CC episode (AG: 14.3%, PG: 47.8%, p = 0.038). Patients with vitamin-D deficiency and/or insufficient vitamin-C supply reported significantly fewer CC episodes in AG than in PG. In the course of the trial, in AG vs. PG the serum vitamin C, folic acid and selenium levels increased (p ? 0.001). The concentration of 25(OH)D3 decreased in both groups, but less so in the AG (AG -8.8%; PG -14%; p = 0.001).

CONCLUSION

Study results show the efficacy of a nutritional medical treatment with a special micronutrient combination in patients susceptible to infections and suffering from recurrent respiratory tract infections.

Vitamin D deficiency is related to worse emotional state

The aim was to evaluate vitamin D levels in young healthy Lithuanian males in winter and to find possible associations of vitamin D concentration to body composition, cognitive functioning, emotional state.

Subjects and Methods A total of 130 healthy males (age range, 18–26 years) were divided into the subgroups according to vitamin D concentration. The Profile of Mood States (POMS) questionnaire and Hospital Anxiety and Depression Scale were employed in the assessment of emotional state. Cognitive functioning was assessed by the Trail Making Test and the Digit Symbol Test of the Wechsler Adult Intelligence Scale.

Results The mean concentration of vitamin D for the entire sample was 13.0±5.3 ng/ml. Only 2 persons (1.6%) had the recommended vitamin D level. Nearly half (45.4%) of study participants had vitamin D deficiency. Lower concentrations were associated with a significantly higher score on the POMS confusion-bewilderment scale. A tendency toward a lower mean depression-dejection score in the participants with a sufficient vitamin D level was observed. Vitamin D concentration correlated positively with body mass index (BMI) and inversely with the confusion-bewilderment score.

In conclusion almost half of the young healthy males participating in the study were detected to have vitamin D deficiency in winter. Low vitamin D concentrations are associated with a worse emotional state.

Serum vitamin D level and prehypertension among subjects free of hypertension

BACKGROUND

Low serum vitamin D levels are associated with high blood pressure (BP). Prehypertension is a preclinical stage where primary prevention efforts have been recommended for delaying or preventing the onset of hypertension. However, the majority of studies examining the association between vitamin D and BP have not accounted for kidney function or systemic inflammation.

METHODS

Participants of the 3rd National Health and Nutrition Examination Survey > 20 years of age and free of hypertension (n = 9,215, 53.5% women) and clinical cardiovascular disease were examined. Serum vitamin D levels were analyzed as quartiles. Prehypertension (n = 3,712) was defined as systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg.

RESULTS

Lower serum vitamin D levels were found to be associated with prehypertension independent of potential confounders including body mass index (BMI), serum cholesterol, C-reactive protein and estimated glomerular filtration rate. Compared to the highest quartile of serum vitamin D (referent), the odds ratio (95% confidence interval) of prehypertension associated with the lowest quartile was 1.48 (1.16-1.90; p trend < 0.0001). This association persisted in subgroup analyses by gender, race-ethnicity and BMI.

CONCLUSION

Lower serum vitamin D levels are associated with prehypertension in a representative sample of US adults.

Diabetes prevalence is associated with serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in US middle-aged Caucasian men and women: a cross-sectional analysis within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

Hypovitaminosis D may be associated with diabetes, hypertension and CHD. However, because studies examining the associations of all three chronic conditions with circulating 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)(2)D) are limited, we examined these associations in the US Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial (n 2465). Caucasian PLCO participants selected as controls in previous nested case-control studies of 25(OH)D and 1,25(OH)(2)D were included in this analysis. Diabetes, CHD and hypertension prevalence, risk factors for these conditions and intake of vitamin D and Ca were collected from a baseline questionnaire. Results indicated that serum levels of 25(OH)D were low (< 50 nmol/l) in 29 % and very low (< 37 nmol/l) in 11 % of subjects. The prevalence of diabetes, hypertension and CHD was 7, 30 and 10 %, respectively. After adjustment for confounding by sex, geographical location, educational level, smoking history, BMI, physical activity, total dietary energy and vitamin D and Ca intake, only diabetes was significantly associated with lower 25(OH)D and 1,25(OH)(2)D levels. Caucasians who had 25(OH)D ≥ 80 nmol/l were half as likely to have diabetes (OR 0·5 (95 % CI 0·3, 0·9)) compared with those who had 25(OH)D < 37 nmol/l. Those in the highest quartile of 1,25(OH)(2)D (≥ 103 pmol/l) were less than half as likely to have diabetes (OR 0·3 (95 % CI 0·1, 0·7)) than those in the lowest quartile (< 72 pmol/l). In conclusion, the independent associations of 25(OH)D and 1,25(OH)(2)D with diabetes prevalence in a large population are new findings, and thus warrant confirmation in larger, prospective studies.

An estimate of the survival benefit of improving vitamin D status in the adult german population

BACKGROUND

Inadequate vitamin D status is a worldwide problem. Evidence is accumulating that individuals with low vitamin D status have excess mortality rates. We calculated to which extent annual mortality rates can be reduced in the German population by optimizing vitamin D status.

RESULTS

Mean serum concentrations of 25-hydroxyvitamin D in the DEVID study cohort were 41 nmol/l (SD: 22 nmol/l). More than 90% of individuals had 25-hydroxyvitamin D concentrations below the threshold that was associated with lowest mortality risk in the two aforementioned trials (75 nmol/l). According to conservative estimations, at least 2.2% of all deaths or 18,300 lives annually can be saved by achieving 25(OH)D concentrations of at least 75 nmol/l in the entire adult German population. Available data provide evidence for an exponential increase in total mortality with deficient 25-hydroxyvitamin D concentrations.

METHODS

Our calculations are based on (1) an annual mortality rate of 1.34% in the adult German population as provided by the Statistical Yearbook, (2) the actual vitamin D status in German adults with a high mortality risk as assessed in 1,343 individuals from 264 general practitioners in different German regions (DEVID study), and (3) data from two very large prospective cohorts (Dobnig et al. 2008; Melamed et al. 2008) about the excess mortality in individuals with inadequate vitamin D status.

CONCLUSION

Improving vitamin D status in a population with inadequate vitamin D status might be an effective strategy to reduce annual mortality rates.

Serum 25-hydroxyvitamin d concentrations and season-specific correlates in Japanese adults

Background

Several lines of evidence indicate an important role for vitamin D in the prevention of a range of diseases. Blood vitamin D levels show clear seasonal variation; however, data on the determinants of vitamin D status for each season are limited. We investigated the association between lifestyle and serum vitamin D concentration by season in Japanese workers.

Methods

Subjects were 312 men and 217 women aged 21 to 67 years who worked in municipal offices in Northern Kyushu, Japan and participated in a periodic checkup in July or November. Multiple linear regression analysis was used to examine the association between serum 25-hydroxivitamin D concentrations and lifestyle factors for each season.

Results

Mean serum 25-hydroxyvitamin D concentration was 27.4 ng/ml (68.4 nmol/L) and 21.4 ng/ml (53.4 nmol/L) for workers surveyed in July and November, respectively (P < 0.001); the prevalence of vitamin D deficiency (<20 ng/ml) was 9.3% and 46.7%, respectively (P < 0.001). In November, dietary vitamin D intake (in both sexes) and nonsmoking and physical activity (in men) were significantly associated with higher concentrations of serum 25-hydroxyvitamin D. In summer, fish/shellfish intake was associated with higher serum 25-hydroxyvitamin D concentrations in women.

Conclusions

Vitamin D deficiency is common in Japanese workers during seasons with limited sunlight. The lifestyle correlates of favorable vitamin D status in November were physical activity, dietary vitamin D intake, and nonsmoking.

Blood 25-hydroxyvitamin D concentration and hypertension: a meta-analysis

OBJECTIVES

Increasing evidence indicates that vitamin D may influence the risk of hypertension, which is a major risk factor for cardiovascular disease. We conducted a meta-analysis to quantitatively review and summarize the results on the association between blood 25-hydroxyvitamin D concentrations and hypertension.

METHODS

Relevant studies were identified by a search of PubMed and EMBASE databases until November 2010. We also reviewed the references of retrieved articles. We included prospective and cross-sectional studies with blood 25-hydroxyvitamin D concentrations as the exposure and hypertension as the outcome. Studies had to report results as a relative risk or an odds ratio. We used random-effects model.

RESULTS

Of the 18 studies included in the meta-analysis, 4 were prospective studies and 14 were cross-sectional studies. The pooled odds ratio of hypertension was 0.73 [95% confidence interval (CI) 0.63-0.84] for the highest versus the lowest category of blood 25-hydroxyvitamin D concentration. In a dose-response meta-analysis, the odds ratio for a 40 nmol/l (16 ng/ml) (approximately 2 SDs) increment in blood 25-hydroxyvitamin D concentration was 0.84 (95% CI 0.78-0.90).

CONCLUSION

Findings from this meta-analysis indicate that blood 25-hydroxyvitamin D concentration is inversely associated with hypertension.

Vitamin d, and kidney disease

Mineral metabolism abnormalities, such as low 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and elevated parathyroid hormone (PTH), are common at even higher glomerular filtration rate than previously described. Levels of 25-hydroxyvitamin D (25(OH)D) show an inverse correlation with those of intact PTH and phosphorus. Studies of the general population found much higher all-cause and cardiovascular (CV) mortality for patients with lower levels of vitamin D; this finding suggests that low 25(OH)D level is a risk factor and predictive of CV events in patients without chronic kidney disease (CKD). 25(OH)D/1,25(OH)2D becomes deficient with progression of CKD. Additionally, studies of dialysis patients have found an association of vitamin D deficiency with increased mortality. Restoration of the physiology of vitamin D receptor activation should be essential therapy for CKD patients.

Duration of physical activity and serum 25-hydroxyvitamin D status of postmenopausal women

PURPOSE

To investigate whether the association between physical activity and serum 25-hydroxyvitamin D (25(OH)D) concentrations is independent of sun exposure, body size, and other potential explanatory variables.

METHODS

By using data from a sample of 1343 postmenopausal women from the Women's Health Initiative, we used linear regression to examine the associations of duration (minutes/week) of recreational activity and of yard work with 25(OH)D concentrations (nmol/L).

RESULTS

In age-adjusted analyses, positive associations were observed between 25(OH)D concentrations and both duration of recreational physical activity (β = 0.71, SE [0.09], p <.001) and yard work (β = 0.36, SE [0.10], p = .004). After further adjustment for vitamin D intake, self-reported sunlight exposure, waist circumference, and season of blood draw, 25(OH)D was significantly associated with recreational activity (β = 0.21, SE [0.09], p = .014) but not with yard work (β = 0.18, SE [0.09], p = .061). Interactions were observed between season and both recreational activity (P(interaction) = .082) and yard work (P(interaction) = .038) such that these activity-25(OH)D associations were greater during summer/fall compared with winter/spring. Self-reported sunlight exposure and measures of body size did not modify the associations.

CONCLUSIONS

The observed age-adjusted activity-25(OH)D associations were attenuated after adjusting for explanatory variables and were modified by season of blood draw. Adopting a lifestyle that incorporates outdoor physical activity during summer/fall, consuming recommended amounts of vitamin D, and maintaining a healthy weight may improve or maintain vitamin D status in postmenopausal women.

Bioavailability of vitamin D₂ from UV-B-irradiated button mushrooms in healthy adults deficient in serum 25-hydroxyvitamin D: a randomized controlled trial

BACKGROUND/OBJECTIVES

Mushrooms contain very little or any vitamin D(2) but are abundant in ergosterol, which can be converted into vitamin D(2) by ultraviolet (UV) irradiation. Our objective was to investigate the bioavailability of vitamin D(2) from vitamin D(2)-enhanced mushrooms by UV-B in humans, and comparing it with a vitamin D(2) supplement.

SUBJECTS/METHODS

Fresh mushrooms were irradiated with an UV-B dose of 1.5 J/cm(2), increasing vitamin D(2) content from <1 to 491 μg/100 g and made to an experimental soup. In this 5-week, single-blinded, randomized, placebo-controlled trial, 26 young subjects with serum 25-hydroxyvitamin D (25OHD) ≤ 50 nmol/l were randomly assigned into three groups ((a) mushroom, (b) supplement and (c) placebo). They received during winter (a) 28,000 IU (700 μg) vitamin D(2) via the experimental soup, or (b) 28,000 IU vitamin D(2) via a supplement or (c) placebo, respectively.

RESULTS

After 2 weeks, serum 25OHD was significantly higher in the mushroom than in the placebo group (P=0.001). The serum 25OHD concentrations in the mushroom and supplement groups rose significantly and similarly over the study period by 3.9 nmol/l (95% confidence interval (95% CI): 2.9, 4.8) and by 4.7 nmol/l per week (95% CI: 3.8, 5.7), respectively.

CONCLUSIONS

We are the first to demonstrate in humans that the bioavailability of vitamin D(2) from vitamin D(2)-enhanced button mushrooms via UV-B irradiation was effective in improving vitamin D status and not different to a vitamin D(2) supplement. This trial was registered at http://germanctr.de as DRKS00000195.

Relationship between 25-hydroxyvitamin D and metabolic syndrome among Jordanian adults

Evidence of the association between 25-hydroxyvitamin D (25(OH)D) and metabolic syndrome (MeS) remains uncertain and incongruent. This study aimed to determine the association between 25(OH)D and MeS among Jordanian adults. A complex multistage sampling technique was used to select a national population-based household sample. The present report deals exclusively with adults aged > 18 years who had complete information on all components of MeS (n = 3,234). A structured questionnaire was used to collect all relevant information. Anthropometric, clinical, and laboratory measurements were obtained. MeS was defined according to the International Diabetes Federation (IDF) definition. Of the total, 42.0% had MeS and 31.7% had 25(OH)D < 30 ng/ml. In a stratified analysis, the prevalence of MeS did not differ significantly between subjects with low and normal 25(OH)D levels for men and women in all age groups. In the multivariate analysis, the odds of MeS were not significantly different between subjects with low and normal 25(OH)D levels (OR = 0.85, 95% CI: 0.70, 1.05, P-value = 0.133). The association between 25(OH)D and MeS remained non-significant when 25(OH)D was analyzed as a continuous variable (OR = 1.004, 95% CI; 1.000, 1.008, P = 0.057) and when analyzed based on quartiles. None of the individual components of MeS were significantly associated with 25(OH)D level. This study does not provide evidence to support the association between 25(OH)D level and MeS or its individual components. Prospective studies are necessary to better determine the roles of 25(OH)D levels in the etiology of MeS.

Older Mayan residents of the western highlands of Guatemala lack sufficient levels of vitamin D

Vitamin D (VitD) levels in older Mayans are currently unknown. Geographic factors, for example, residences in areas receiving ample sunlight at high altitudes and latitudes near the equator, would favor optimum VitD levels, whereas demographic factors, for example, darker skin pigmentation, clothing practices, and older age, would favor low 25-hydroxy-vitamin D, or 25(OH)D, levels. Conjecturing that demographic factors affecting VitD status might outweigh geographic factors in this population, we hypothesized that older Mayans have suboptimal values of 25(OH)D. We also hypothesized that older Mayans in rural areas would have higher VitD levels than would their urban counterparts. Blood samples were collected from 108 healthy older Mayans (mean age, 69 years) from urban (n = 84, 50% male) and rural settings (n = 24, 50% male) during the summer of 2008 in the highlands of Quetzaltenango, Guatemala. We assessed 25(OH)D concentrations by radioimmunoassay in a US-based laboratory. Mean (SD) serum 25(OH)D values were 53.3 (15.0) nmol/L, and lower 25(OH)D values were associated with increasing age (r = -0.58, P = .004). Of all subjects, 3.7% (n = 4) maintained an optimal status of 25(OH)D (>80 nmol/L), 50% (n = 54) had values between 50 and 80 nmol/L, and 46.3% (n = 50) had levels less than 50 nmol/L. Urban subjects had nonsignificantly higher 25(OH)D values (55.0 ± 15.3 nmol/L) than did rural subjects (47.4 ± 12.4 nmol/L, P = .228). Men had significantly higher values (58.2 ± 16.5 nmol/L) than did women (48.4 ± 11.6 nmol/L, P = .001). We conclude that despite residing in an optimal geographic location to receive adequate sunlight exposure, most older Guatemalan Mayans in Quetzaltenango have suboptimal levels of VitD.

Confirmed hypertension and plasma 25(OH)D concentrations amongst elderly men

OBJECTIVES

the results of experimental studies suggest that vitamin D deficiency activates the renin-angiotensin system and predisposes to hypertension. Results of previous epidemiological studies investigating the association between 25-hydroxyvitamin D [25(OH)D] status and hypertension have not been consistent, perhaps because of their sole reliance on office blood pressure (BP) measurements leading to some misclassification of hypertension status. No previous studies have examined the association between 25(OH)D status and confirmed hypertension assessed with both office and 24-h BP measurements.

DESIGN

in this cross-sectional study, we investigated 833 Caucasian men, aged 71 ± 0.6 years, to determine the association between plasma 25(OH)D concentrations, measured with high-pressure liquid chromatography mass spectrometry, and the prevalence of hypertension. We used both supine office and 24-h BP measurements for classifying participants as normotensive or confirmed hypertensive; participants with inconsistent classifications were excluded.

RESULTS

in a multivariable adjusted logistic regression model, men with 25(OH)D concentrations <37.5 nmol L(-1) had a 3-fold higher prevalence of confirmed hypertension compared to those with ≥ 37.5 nmol L(-1) 25(OH)D (odds ratio = 3.3, 95% CI: 1.0-11.0).

CONCLUSIONS

our results show that low plasma 25(OH)D concentration is associated with a higher prevalence of confirmed hypertension.

Efficient tetanus toxoid immunization on vitamin D supplementation

BACKGROUND/OBJECTIVES

Vitamin D mediates immunomodulatory functions, and its deficiency has been associated with an increased prevalence of immunological diseases. The supplementation of vitamin D might be therapeutically beneficial, for example, in lupus erythematosus patients. However, its affect on established recall immune responses is undefined.

SUBJECTS/METHODS

In all, 32 individuals were randomized in a placebo controlled, double-blind setting, and received vitamin D (daily 2000 IU) for 10 weeks followed by tetanus toxoid (TT) booster immunization.

RESULTS

During vitamin D supplementation the median 25-hydroxyvitamin D serum concentration increased to 80.3 nM, which as expected decreased in the placebo group to 29.1 nM during the ultraviolet-deprived winter months. The TT-specific immunoglobulin G (IgG) boost efficiency was marginal higher in the vitamin D group (P = 0.04). The increase of the 25-hydroxyvitamin D levels correlated with the increase of TT-IgG serum concentrations. The induction of specific serum IgA and specific antibody secreting cells was comparable between both groups. Accordingly, the TT-specific and polyclonally triggered T-cell cytokine profiles were stable as well.

CONCLUSIONS

Vitamin D supplementation was successful and booster immunization induced efficiently specific antibodies titers.

Inverse association between dietary vitamin D and risk of cutaneous melanoma in a northern Italy population

The possibility of an inverse association between vitamin D and risk of cancer and, in particular, of cutaneous malignant melanoma has been suggested, but results of epidemiologic studies are still conflicting. We examined the relation between dietary vitamin D intake and melanoma risk through a population-based case-control study (380 cases, 719 controls) in a northern region of Italy, a country with an average vitamin D intake lower than that in northern Europe or the United States. We assessed average daily intake of vitamin D from foodstuffs using the European Prospective Investigation into Cancer and Nutrition (EPIC) semiquantitative food frequency questionnaire. In this population, levels of vitamin D intake were considerably lower than those observed in recent U.S. studies. We found an inverse relation between dietary vitamin D and melanoma risk in the sample as a whole, in both crude and adjusted analyses. In sex- and age-specific analyses, this association appeared to be stronger among males and among older subjects. These findings suggest that, at the relatively low levels of intake observed in this sample, an inverse relation between dietary vitamin D and risk of cutaneous malignant melanoma may exist.

Extraskeletal effects of vitamin D: facts, uncertainties, and controversies

Vitamin D was long viewed as a hormone acting chiefly to regulate calcium-phosphate metabolism and bone mineralization. Over the last decade, however, basic science and clinical researchers have produced a bewildering amount of information on the extraskeletal effects of vitamin D. This article is a review of the clinical and biological actions of vitamin D including effects on the immune system, auto-immune diseases, infections, cancer, metabolic syndrome, fall risk, cognitive function, and muscle function.

The estimated benefits of vitamin D for Germany

This article gives an overview of the vitamin D status in Germany, provides evidence for an independent association of vitamin D deficiency with various chronic diseases, and discusses preventive measures for improving vitamin D status in Germany. The prevalence of vitamin D insufficiency is 40-45% in the general German population. An additional 15-30% are vitamin D deficient. Vitamin D can prevent falls and osteoporotic fractures in older people. There is also accumulating evidence that vitamin D may prevent excess mortality and may probably prevent some chronic diseases that occur in early life such as type 1 diabetes and multiple sclerosis. Adherence to present sun safety policy (avoidance of the sun between 11 am and 3 pm) and dietary recommendations (5-10 microg daily for adults) would, however, definitively lead to vitamin D deficiency. The estimated cost saving effect of improving vitamin D status in Germany might be up to 37.5 billion euro annually. It should be the goal of nutrition and medical societies to erase vitamin D deficiency in Germany within the next 5-10 years. To achieve this goal, the daily production of at least 25 microg of vitamin D in the skin or an equivalent oral intake should be guaranteed.

[The significance of vitamin D metabolism in human skin. An update]

Vitamin D deficiency is endemic, affecting worldwide approximately more than 1 billion people and approximately 60% of the German population. In recent years, our understanding of the important role of vitamin D for human health has grown enormously. Epidemiological and in vitro investigations as well as animal studies have convincingly demonstrated new important functions of vitamin D, including potent immunoregulatory and growth regulatory properties. We know today that vitamin D deficiency/insufficiency is not exclusively associated with an increased risk for bone diseases, but with a multitude of other diseases (including various types of cancer, cardiovascular diseases, infectious diseases, and autoimmune diseases). We discuss our present understanding of the importance of the cutaneous vitamin D system.