Prevalence and predictors of vitamin D deficiency in healthy adults

Vitamin D levels and their associations with survival and major disease outcomes in a large cohort of patients with chronic graft-vs-host disease

AIM

To identify the factors associated with vitamin D status in patients with chronic graft-vs-host disease (cGVHD) and evaluate the association between serum vitamin D (25(OH)D) levels and cGVHD characteristics and clinical outcomes defined by the National Institutes of Health (NIH) criteria.

METHODS

310 cGVHD patients enrolled in the NIH cGVHD natural history study (clinicaltrials.gov: NCT00092235) were analyzed. Univariate analysis and multiple logistic regression were used to determine the associations between various parameters and 25(OH)D levels, dichotomized into categorical variables: ≤20 and >20 ng/mL, and as a continuous parameter. Multiple logistic regression was used to develop a predictive model for low vitamin D. Survival analysis and association between cGVHD outcomes and 25(OH)D as a continuous as well as categorical variable: ≤20 and >20 ng/mL; <50 and ≥50 ng/mL, and among three ordered categories: ≤20, 20-50, and ≥50 ng/mL, was performed.

RESULTS

69 patients (22.3%) had serum 25(OH)D ≤20 ng/mL. Univariate analysis showed that supplement intake, nutritional status (severely malnourished, moderately malnourished, well-nourished), race (African-American, other), and estimated creatinine clearance (eCCr) were associated with 25(OH)D levels. A predictive model was developed based on supplement intake, nutritional status, race, and eCCr, accurately predicting 77.9% of patients with 25(OH)D ≤20 and 65.2% of those with 25(OH)D >20 ng/mL. No association was found between vitamin D and major cGVHD characteristics, but patients with 25(OH)D ≤20 ng/mL had somewhat decreased survival.

CONCLUSION

Nutritional status and adequate supplementation are important to maintain 25(OH)D >20 ng/mL in cGVHD patients. Intervention studies and more research is needed to reveal the underlying mechanism of vitamin D metabolism in cGVHD setting.

VITAMIN D STATUS IN PATIENTS WITH MENTAL DISORDERS: A CROSS-SECTIONAL ANALYSIS OF SINGLE COHORT FROM ROUTINE PRACTICE

Context

Clinical research suggests that vitamin D deficiency correlates with mental illnesses.

Objective

The aim was to prove that the patients from the psychiatric health care service in Serbia had higher vitamin D deficiency than patients from general practice.

Design

The study had a cross-sectional design.

Methods

The study included 47 patients aged 19 - 76 of both sexes with different mental disorders. We performed sample size calculation on available data for vitamin D deficiency in patients in health care facilities compared with the general population. The concentrations of vitamin D in serums were measured by HPLC (high performance/pressure liquid chromatography).

Results

The mean value of vitamin D (standard deviation) in the whole group of study subjects was 16.27(10.62) ng/mL; 68.1% of the patients had a deficiency of vitamin D (25(OH)D<20 ng/mL). The difference is statistically significant from expected proportion of people with vitamin D deficiency in general practice (p=0.040). Serum concentrations of 25(OH)D were significantly correlated with serum concentrations of phosphorus (ϱ=0.336, p=0.024) and sodium (ϱ=0.304, p=0.038).

Conclusions

The patients of psychiatry health care had significantly higher frequency of vitamin D deficiency than expected. There is a significant association between serum levels of vitamin D, and phosphate and sodium.

Investigating potential exogenous tumor initiating and promoting factors for Cutaneous T-Cell Lymphomas (CTCL), a rare skin malignancy

Most skin malignancies are caused by external and often preventable environmental agents. Multiple reports demonstrated that cutaneous T-cell lymphomas (CTCL) can occur in married couples and cluster in families. Furthermore, recent studies document geographic clustering of this malignancy in Texas as well as in other areas of the United States. Multiple infectious, occupational, and medication causes have been proposed as triggers or promoters of this malignancy including hydrochlorothiazide diuretics, Staphylococcus aureus, dermatophytes, Mycobacterium leprae, Chlamydia pneumoniae, human T-Cell lymphotropic virus type 1 (HTLV1), Epstein-Barr virus (EBV), and herpes simplex virus (HSV). In this report, we review recent evidence evaluating the involvement of these agents in cancer initiation/progression. Most importantly, recent molecular experimental evidence documented for the first time that S. aureus can activate oncogenic STAT3 signaling in malignant T cells. Specifically, S. aureus Enterotoxin type A (SEA) was recently shown to trigger non-malignant infiltrating T cells to release IL-2 and other cytokines. These signals upon binging to their cognate receptors on malignant T cells are then able to activate STAT3 and STAT5 oncogenic signaling and promote cancer progression and IL-17 secretion. In light of these findings, it might be important for patients with exacerbation of their CTCL symptoms to maintain high index of suspicion and treat these individuals for S. aureus colonization and/or sepsis with topical and systemic antibiotics.

Multiple Endocrine Disruption by the MET/ALK Inhibitor Crizotinib in Patients With Non-small Cell Lung Cancer

OBJECTIVES

Non-small cell lung cancer (NSCLC) is a heterogenous group of disorders that can be subclassified based upon molecular characterization. Anaplastic lymphoma kinase translocation and MET aberrations occur in a subset of NSCLC. Anaplastic lymphoma kinase/MET have been shown to be inhibited by the small molecule tyrosine kinase inhibitor crizotinib. Recently, crizotinib was shown to decrease testosterone in males. Herein, we describe the effects of crizotinib on multiple hormonal axes.

MATERIALS AND METHODS

Seven consecutive patients with NSCLC who were receiving crizotinib as part of their standard care were evaluated for hormonal disruptions.

RESULTS

Primary hypogonadism was detected in 4/5 of males, whereas mildly elevated prolactin was observed in 4/7 patients. Hypocalcemia was observed in 3/7 patients. Interestingly, 5/7 patients had elevated levels of insulin-like growth factor-1 (IGF-1) levels, and the remaining 2 individuals had levels that were near the upper limits of the normal range.

CONCLUSIONS

Because of cellular cross-talk between MET and IGF-1 signaling, elevated IGF-1 levels induced by crizotinib treatment may have implications for long-term drug efficacy. Furthermore, this finding suggests a potential avenue of therapeutic synergy, namely coordinate inhibition of the MET and IGF-1 signaling pathways. Finally, as crizotinib has been recently approved, it is prudent to check hormone and calcium biomarkers and correct noted deficiencies for improved outcomes and quality of life.

Vitamin D deficiency in alopecia areata

BACKGROUND

Alopecia areata (AA) is a T cell-mediated autoimmune disease that causes inflammation around anagen-stage hair follicles. Insufficient levels of vitamin D have been implicated in a variety of autoimmune diseases. Previous reports have described the effects of vitamin D on hair follicles.

OBJECTIVES

To evaluate the status of vitamin D in patients with AA, and the relationship between vitamin D levels and disease severity.

METHODS

A cross-sectional study of 86 patients with AA, 44 patients with vitiligo and 58 healthy controls was conducted. The serum vitamin D levels of the study group were determined by liquid chromatography/tandem mass spectrometry.

RESULTS

Serum 25-hydroxyvitamin D [25(OH)D] levels in patients with AA were significantly lower than those of the patients with vitiligo and the healthy controls (P = 0·001 and P < 0·001, respectively). The prevalence of 25(OH)D deficiency was significantly higher in patients with AA (91%) compared with patients with vitiligo (71%) and healthy controls (33%) (P = 0·003 and P < 0·001, respectively). Furthermore, a significant inverse correlation was found between disease severity and serum 25(OH)D level in patients with AA (r = -0·409; P < 0·001).

CONCLUSIONS

Deficient serum 25(OH)D levels are present in patients with AA and inversely correlate with disease severity. Accordingly, screening patients with AA for vitamin D deficiencies seems to be of value for the possibility of supplementing these patients with vitamin D.

Vitamin D Status in an Elective Orthopedic Surgical Population

BACKGROUND

Adequate vitamin D availability is required for normal bone metabolism. Hypovitaminosis D is highly prevalent in latitudes above 30 degrees. The goal of this prospective study was to determine the prevalence of hypovitaminosis D in an unselected population of patients undergoing major ankle or hindfoot arthrodesis in Burlington, Vermont (latitude 44.5° N).

METHODS

One hundred eighteen patients undergoing a major ankle, hindfoot, or midfoot arthrodesis between May 2012 and February 2014 were eligible for the study, of which 81 participated. All clinical data, including comorbidities, demographics, and lab values, were obtained from the comprehensive electronic medical record system that encompassed all inpatient and outpatient care. Based on the recommendations published by the Vitamin D Task Force Committee of the Endocrine Society, vitamin D levels above 30 ng/mL were considered normal. Statistical analyses were performed using a significance level of P <.05.

RESULTS

Of 81 patients tested, 54 (67%) had low serum vitamin D. Older patients had lower risk for hypovitaminosis D (RR = 0.953, CI = 0.908, 0.999, P = .046), whereas a Charlson Index ≥3 had increased risk (RR = 16.8, CI = 1.5, 192.3, P = .023). Of the 16 patients retested after vitamin supplementation, only 9 (56%) corrected to normal.

CONCLUSIONS

In an unselected population in Vermont undergoing hindfoot and ankle arthrodesis, there was a high prevalence of hypovitaminosis D, even in patients without predisposing risk factors. Consequently, routine testing or presumptive high-dose vitamin D replenishment therapy should be considered for all patients scheduled for such surgery, primarily to promote adequate skeletal calcium metabolism.

LEVEL OF EVIDENCE

Level II, prospective study.

Emerging therapy in arthritis: Modulation of markers of the inflammatory process

The induction of tolerance has been proposed as a therapeutic strategy for arthritis aiming to decrease progression of the pathology, probably by promoting suppressor mechanisms of the autoimmune response. This work aimed to confirm whether the treatment with vitamin D3 could synergize oral tolerance induced by hydrolyzed collagen peptides, in our experimental model of antigen induced arthritis in New Zealand rabbits. Clinical observation of the phenomenon indicates that simultaneous treatment with hydrolyzed collagen peptides and vitamin D3 was beneficial when compared with no treatment, for arthritic animals, and for arthritic animals that received treatment with only hydrolyzed collagen peptides or vitamin D3. Treatment with hydrolyzed collagen peptides caused diminished proinflammatory cytokine levels, an effect synergized significantly by the simultaneous treatment with vitamin D3. The anatomical-pathological studies of the animals that received both treatments simultaneously showed synovial tissues without lymphocytic and plasma cell infiltrates, and without vascular proliferation. Some of the synovial tissue of the animals of these groups showed a slight decrease in Galectin-3 expression. We propose that simultaneous oral treatment with vitamin D3 and hydrolyzed collagen peptides could increase the immunoregulatory effect on the process of previously triggered arthritis. We used articular cartilage hydrolysate and not collagen II because peptides best expose antigenic determinants that could induce oral tolerance. Oral tolerance may be considered in the design of novel alternative therapies for autoimmune disease and we have herein presented novel evidence that the simultaneous treatment with vitamin D3 may synergize this beneficial effect.

25-hydroxyvitamin D serum level in children of different ethnicity living in Italy

Several factors including ethnicity are known to influence 25(OH)D levels. The purpose of our study was to assess 25(OH)D levels among 1374 pediatric subjects of different ethnicity and to determine the prevalence of vitamin D deficiency and insufficiency among different ethnic groups. The prevalence of 25(OH)D ≤ 20 ng/ml was 44.2, 65.2, 69.2, 54.0, and 44.8 % among Caucasians, Africans, North Africans, Indians, and others, respectively (P < 0.001). The median of 25(OH)D was 21.0 ng/ml (IQR = 14.0-29.6 ng/ml) for the cohort. Season of blood sampling, age, ethnicity, gestational age, birth weight, and z-score BMI were associated with 25(OH)D levels. Caucasians had higher median 25(OH)D levels than sub-Saharan Africans (P < 0.001), North Africans (P < 0.001), and Indians (P < 0.001). There were no significant differences in the median 25(OH)D levels between ethnic groups among infants, whereas for children older than 1 year we found significant differences in 25(OH)D levels in the different ethnic groups, compared to Caucasians.

CONCLUSION

Ethnicity was correlated with 25(OH)D levels among children older than 1 year. We found a high prevalence of vitamin D deficiency and insufficiency after the first year of life, and this was more remarkable in non-Caucasian children.

24,25-Dihydroxyvitamin d3 and vitamin D status of community-dwelling black and white Americans

BACKGROUND

24,25-Dihydroxyvitamin D [24,25(OH)2D] is a metabolite of 25-hydroxyvitamin D (25D). Blacks frequently have low total 25D without manifestations of vitamin D deficiency, suggesting that total serum 25D may incorrectly reflect vitamin D status in different racial groups. The ratio of serum 24,25(OH)2D to 25D [vitamin D metabolite ratio (VMR)] represents a new candidate biomarker for vitamin D status.

METHODS

We measured 24,25(OH)2D3 and 25D3 by mass spectrometry in a random community cohort of black (n = 212) and white (n = 164) Americans to evaluate VMR as a marker for vitamin D status. We measured parathyroid hormone concentrations by immunoassay to compare VMR and 25D3 against a physiological indicator of vitamin D deficiency.

RESULTS

Serum 24,25(OH)2D3 strongly correlated with 25D3 in both black and white study participants (r = 0.90, P < 0.001 and r = 0.86, P < 0.001 respectively). Blacks had lower mean 25D3 than whites [17.0 (7.8) vs 27.5 (11.3) ng/mL; 42.4 (19.5) vs 68.6 (28.2) nmol/L, P < 0.001] and lower mean 24,25(OH)2D3 [2.1 (1.3) vs 3.6 (2.0) ng/mL; 5.1 (3.1) vs 8.7 (4.8) nmol/L, P < 0.001]. In contrast to total 25D3 concentrations, mean VMR values were similar in blacks and whites [11.9 (4.0) vs 12.5 (3.4), P = 0.16, respectively] and were negatively correlated with parathyroid hormone concentrations in both races (rs = -0.26, P < 0.001, and rs = -0.25, P < 0.001, respectively).

CONCLUSIONS

Our results provide further evidence that measurement of total 25D for assessment of vitamin D status in patients of African descent deserves reevaluation and suggest that alternative measures such as VMR should be considered.

Current views on the etiopathogenesis, clinical manifestation, diagnostics, treatment and correlation with other nosological entities of SIBO

Small intestinal bacterial overgrowth (SIBO) is a disease of great clinical and socioeconomic importance caused by an excessive amount of bacteria in the upper alimentary tract. Physiological microbiota are replaced by pathogenic bacteria mainly from large intestine, which is called dysbacteriosis. SIBO disturbs digestion and absorption in the alimentary tract, which seems to cause inflammation. SIBO affects the morphology and function of the digestive system and causes systemic complications (e.g. osteoporosis, macrocytic anemia). Inflammation interferes with gene expression responsible for producing and secreting mucus, therefore, a correlation between SIBO and cystic fibrosis, irritable bowel syndrome and chronic abdominal pain are postulated. All conditions leading to bacterial growth such as congenital and anatomical abnormalities in the digestive tract, motility disorder or immunological deficits are risk factors of SIBO. A typical clinical manifestation of SIBO comprises meteorism, enterectasia, abdominal discomfort and diarrhea. Diagnostic procedures such as glucose, lactulose, methane, 13C mixed triglyceride breath tests are being used in diagnosing SIBO.

Prevalence of renal abnormalities in chronic HBV infection: the HARPE study

BACKGROUND & AIMS

Few data are available on the prevalence of renal abnormalities in chronic hepatitis B virus (HBV)-infected patients. The multicentric cross-sectional HARPE study evaluated the prevalence of kidney disease indicators, in chronic HBV surface antigen carriers patients (HBsAg+) with active or inactive infection.

PATIENTS AND METHODS

Two hundred and sixty-eight HBsAg+ adult patients, naïve of any oral antihepatitis B virus treatment were prospectively included over 2 years. Data for renal assessment were collected once from patient files. Univariate tests and multiple linear regressions were performed with the SAS software, version 8.02 (SAS, Inc., Cary, NC, USA).

RESULTS

Among the 260 patients analysed, 58% were men, the mean age was 42 ± 14 years, 59.6% were inactive carriers whereas 47 patients, mostly active, were about to start an antiviral therapy. Prevalence of proteinuria, haematuria, glycosuria, uninfectious leukocyturia was 38.1%, 20.6%, 3.9% and 9% respectively. According to the international definition, a total of 64.6% of patients were found to have kidney disease. Diabetes, hypertension and dyslipidaemia were observed, respectively, in 4.6%, 9.2% and 38.8% patients. There were no significant differences in these results within the three subgroups.

CONCLUSION

Renal abnormalities are highly prevalent in our population and pre-exist before the initiation of any antihepatitis B virus treatment. This emphasizes the need for: (i) a baseline renal evaluation in all HBs antigen-positive patients; (ii) a regular renal monitoring before and during antihepatitis B virus treatment to diagnose and manage renal impairment and adjust antihepatitis B virus treatment doses to renal function when necessary.

Vitamin D and assisted reproduction: should vitamin D be routinely screened and repleted prior to ART? A systematic review

PURPOSE

To review the current literature regarding the role of vitamin D status in pregnancy outcomes in women undergoing assisted reproductive technology (ART) and to assess cost-effectiveness of routine vitamin D deficiency screening and repletion prior to initiation of ART.

METHODS

A systematic literature review was conducted using PubMed. Relevant study outcomes were compared among the selected studies. A cost-benefit analysis was performed using a decision tree mathematical model with sensitivity analyses from the perspective of direct societal cost. Published data were used to estimate probabilities and costs in 2014 US dollars.

RESULTS

Thirty-four articles were retrieved, of which eight met inclusion criteria. One study demonstrated a negative relationship between vitamin D status and ART outcomes, while two studies showed no association. The remaining five studies concluded that ART outcomes improved after vitamin D repletion.

CONCLUSION

The majority of reviewed studies reported a decrement in ART outcomes in patients with vitamin D deficiency. Cost-benefit analyses suggested that screening and supplementing vitamin D prior to ART might be cost effective, but further evidence is needed. Given the absence of Level I evidence regarding vitamin D status and ART outcomes, full endorsement of routine vitamin D screening and supplementation prior to ART is premature.

Vitamin D deficiency is associated with increased fecal incontinence symptoms

INTRODUCTION AND HYPOTHESIS

Vitamin D is an important micronutrient in muscle function. We hypothesize that vitamin D deficiency may contribute to fecal incontinence (FI) symptoms by affecting the anal continence mechanism. Our goal was to characterize the association of vitamin D deficiency as a variable affecting FI symptoms and its impact on health-related quality of life (HR-QoL).

METHODS

This case-control study assessed women seen at a tertiary-care referral center. Participants were identified as having had a serum vitamin D level obtained within a year of their visit: cases were women presenting for care for FI symptoms; controls were women without any pelvic floor symptoms presenting to the same clinical site for general gynecologic care. Cases completed the Modified Manchester Health Questionnaire (MMHQ) and the Fecal Incontinence Severity Index to measure symptom severity and burden on QoL.

RESULTS

Among the 31 cases and 81 controls, no demographic or medical differences existed. Women with FI had lower vitamin D levels (mean 29.2 ± 12.3 cases vs. 35 ± 14.1 ng/ml controls p = 0.04). The odds of vitamin D deficiency were higher in women with FI compared with controls [odds ratio (OR) 2.77, 95 % confidence interval (CI) 1.08-7.09]. Among cases, women with vitamin D deficiency (35 %) had higher MMHQ scores, indicating greater FI symptom burden [51.3 ± 29.3 (vitamin D deficient) vs. 30 ± 19.5 (vitamin D sufficiency), p = 0.02]. No differences were noted for FI severity, p = 0.07.

CONCLUSIONS

Vitamin D deficiency is prevalent in women with fecal incontinence and may contribute to patient symptom burden.

Vitamin D supplements improve urticaria symptoms and quality of life in chronic spontaneous urticaria patients: A prospective case-control study

Vitamin D plays an important role in the immune system; decreased serum vitamin D concentrations have been linked to dysregulated immune function. Low vitamin D status is probably associated with chronic spontaneous urticaria (CSU). We evaluated the prevalence of low vitamin D status, and the clinical response and quality of life following vitamin D supplementation, in a prospective case-control study with 60 CSU patients and 40 healthy individuals. Serum 25-hydroxy vitamin D (25(OH)D) concentrations were measured at baseline and after 6 weeks. For patients with 25(OH)D concentrations < 30 ng/ml, treatment included 20,000 IU/day of ergocalciferol (vitamin D2) and non-sedative antihistamine drugs for 6 weeks. Urticaria symptom severity and quality of life were assessed based on the Urticaria Activity Score over 7 days (UAS7) and the Dermatology Life Quality Index (DLQI). Of the 100 participants, 73% were female; the mean age was 39 ± 16 years. Vitamin D deficiency (measured as 25(OH)D < 20 ng/ml) was significantly higher in the CSU group than the control group. The median 25(OH)D concentration for the CSU group, 15 (7 - 52) ng/ml was significantly lower than for control group, 30 (25 - 46) ng/ml. Overall, 83% (50/60) of CSU patients (25(OH)D < 30 ng/ml) were treated with ergocalciferol (vitamin D2) supplementation; after 6 weeks, these patients showed significant improvements in UAS7 and DLQI scores compared with the non-vitamin D supplement group. This study revealed a significant association of lower serum 25(OH)D concentrations with CSU. Vitamin D supplements might improve symptoms and quality of life in CSU patients.

Prevalence and risk factors of vitamin D deficiency in inherited ichthyosis: a French prospective observational study performed in a reference center

BACKGROUND

To date, few studies have investigated serum vitamin D status in patients with inherited ichthyosis. The aim of this study was to determine the prevalence of vitamin D deficiency (defined as serum level <10 ng/mL) in a French cohort of patients and to identify associated risk factors.

METHODS

This was a prospective observational study performed in a hospital reference center with expertise for rare skin diseases. Patients' clinical characteristics were recorded. Serum concentration of 25-hydroxyvitamin D and parathyroid hormone were determined. For patients with vitamin D deficiency, serum calcium, serum phosphorus and bone mineral density were also investigated. Comparisons between groups (25-hydroxyvitamin D <10 ng/mL versus ≥10 ng/mL) were conducted by univariate and multivariate logistic regression.

RESULTS

Of the 53 included patients, 47 (88.7%) had serum 25-hydroxyvitamin D below the optimal level of 30 ng/mL: 18 (34%) had vitamin D sufficiency, 14 (26.4%) had vitamin D insufficiency, and 15 (28.3%) had vitamin D deficiency. A negative linear correlation was found between 25-hydroxyvitamin D and parathyroid hormone levels for the whole study population. Serum calcium and phosphorus levels were normal for the 15 patients with vitamin D deficiency. Bone mineral density was investigated for 11 of these latter 15 patients, and six of them had osteopenia. Winter/spring seasons of vitamin D measurement, severity of ichthyosis, and phototypes IV-VI were identified as independent risk factors for vitamin D deficiency.

CONCLUSIONS

Clinicians should be aware of the risk of vitamin D deficiency in the management of patients with inherited ichthyosis, especially in winter and spring, and in case of dark skin or severe disease.

Knowledge, attitude and practice regarding solar ultraviolet exposure among medical university students in Northeast China

To assess the knowledge, attitudes and practices regarding the health effects of ultraviolet radiation (UVR) and sun exposure among medical university students in Northeast China, 385 subjects were investigated on October 2013 using a self-administered multiple-choice questionnaire. Most of the subjects knew the effects of UVR on skin cancer (95.6%) and sunburn (92.2%), but fewer knew of the eye damage that can result from UVR (27.8% cataract and 3.1% pterygium). Correspondingly, the main purpose of adopting sun protection was considered to be 'preventing sunburn' (55.4%), but 'preventing eye damage' was the least (1.8%). In actual behaviour, the eyes received the least protection as well. Although knowing the effects of UVR on vitamin D synthesis (87.3%), 66.8% of participants never or seldom increased sun exposure. Compared to men, women were more likely to reduce sun exposure (P<0.001). Only a small fraction of subjects (6.6%) thought that tanning was attractive. Considering the response variability to UVR in people with different skin colours, different sun protection programs should be provided. In China, especially in the North, the public should be educated to moderately increase sun exposure to maintain adequate vitamin D status while also protecting against eye damage from UVR.

Prevalence of Abnormal Vitamin D Levels Among Division I NCAA Athletes

Background:

Up to 1 billion people have insufficient or deficient vitamin D levels. Despite the well-documented, widespread prevalence of low vitamin D levels and the importance of vitamin D for athletes, there is a paucity of research investigating the prevalence of vitamin D deficiency in athletes.

Hypothesis:

We investigated the prevalence of abnormal vitamin D levels in National Collegiate Athletic Association (NCAA) Division I college athletes at a single institution. We hypothesized that vitamin D insufficiency is prevalent among our cohort.

Study Design:

Cohort study.

Level of Evidence:

Level 1.

Methods:

We measured serum 25-hydroxyvitamin D (25(OH)D) levels of 223 NCAA Division I athletes between June 2012 and August 2012. The prevalence of normal (≥32 ng/mL), insufficient (20 to <32 ng/mL), and deficient (<20 ng/mL) vitamin D levels was determined. Logistic regression was utilized to analyze risk factors for abnormal vitamin D levels.

Results:

The mean serum 25(OH)D level for the 223 members of this study was 40.1 ± 14.9 ng/mL. Overall, 148 (66.4%) participants had sufficient 25(OH)D levels, and 75 (33.6%) had abnormal levels. Univariate analysis revealed the following significant predictors of abnormal vitamin D levels: male sex (odds ratio [OR] = 2.83; P = 0.0006), Hispanic race (OR = 6.07; P = 0.0063), black race (OR = 19.1; P < 0.0001), and dark skin tone (OR = 15.2; P < 0.0001). Only dark skin tone remained a significant predictor of abnormal vitamin D levels after multivariate analysis (adjusted OR = 15.2; P < 0.0001).

Conclusion:

In a large cohort of NCAA athletes, more than one third had abnormal vitamin D levels. Races with dark skin tones are at much higher risk than white athletes. Male athletes are more likely than female athletes to be vitamin D deficient. Our study demonstrates a high prevalence of vitamin D deficiency among healthy NCAA athletes.

Clinical Relevance:

Many studies indicate a significant prevalence of vitamin-D insufficiency across various populations. Recent studies have demonstrated a direct relationship between serum 25(OH)D levels and muscle power, force, velocity, and optimal bone mass. In fact, studies examining muscle biopsies from patients with low vitamin D levels have demonstrated atrophic changes in type II muscle fibers, which are crucial to most athletes. Furthermore, insufficient 25(OH)D levels can result in secondary hyperparathyroidism, increased bone turnover, bone loss, and increased risk of low trauma fractures and muscle injuries. Despite this well-documented relationship between vitamin D and athletic performance, the prevalence of vitamin D deficiency in NCAA athletes has not been well studied.

Serum 25 hydroxyvitamin D in employees of a Middle Eastern university hospital

BACKGROUND

The Middle East registers the highest rate of vitamin D deficiency worldwide. In Lebanon, previous studies looked at this deficiency in schoolchildren, university students, young adults and postmenopausal women. However, no previous study was performed in hospital workers. The objective of our study was to evaluate vitamin D status in a Beirut hospital center and to look at the potential factors influencing these measurements.

METHODS

This cross-sectional study was performed on hospital employees who came for a regular checkup at the primary health-care department. 25(OH)D measurements were performed using the Dia-Sorin chemiluminescent assay.

RESULTS

392 subjects (318 women and 74 men) were included in the study. The mean age of the participants was 41.02 ± 11.3 years. The mean 25(OH)D level was 15.61 ± 7.91 ng/ml, with no significant difference according to gender. There were no significant correlations between 25(OH)D and both BMI and age, but 25(OH)D was significantly associated with educational level (p = 0.03). There was a significant difference in 25(OH)D levels according to season (p < 0.001) and a significant association between 25(OH)D and the reported weekly hours of sun exposure (r = 0.1, p = 0.032), but not with the reported sunscreen use. Fish consumption was positively associated with 25(OH)D levels (p = 0.018), while milk, dairy product or egg consumption did not achieve any significant relationship. In a stepwise linear regression analysis, fish consumption and season were the only independent predictors of 25(OH)D levels (p = 0.007 and p = 0.0001 respectively).

CONCLUSION

Vitamin D deficiency is common among hospital workers. This finding reinforces the need for vitamin D supplementation in these high-risk populations.

Vitamin D-binding protein and vitamin D status of black Americans and white Americans

BACKGROUND

Low levels of total 25-hydroxyvitamin D are common among black Americans. Vitamin D-binding protein has not been considered in the assessment of vitamin D deficiency.

METHODS

In the Healthy Aging in Neighborhoods of Diversity across the Life Span cohort of blacks and whites (2085 participants), we measured levels of total 25-hydroxyvitamin D, vitamin D-binding protein, and parathyroid hormone as well as bone mineral density (BMD). We genotyped study participants for two common polymorphisms in the vitamin D-binding protein gene (rs7041 and rs4588). We estimated levels of bioavailable 25-hydroxyvitamin D in homozygous participants.

RESULTS

Mean (±SE) levels of both total 25-hydroxyvitamin D and vitamin D-binding protein were lower in blacks than in whites (total 25-hydroxyvitamin D, 15.6±0.2 ng per milliliter vs. 25.8±0.4 ng per milliliter, P<0.001; vitamin D-binding protein, 168±3 μg per milliliter vs. 337±5 μg per milliliter, P<0.001). Genetic polymorphisms independently appeared to explain 79.4% and 9.9% of the variation in levels of vitamin D-binding protein and total 25-hydroxyvitamin D, respectively. BMD was higher in blacks than in whites (1.05±0.01 g per square centimeter vs. 0.94±0.01 g per square centimeter, P<0.001). Levels of parathyroid hormone increased with decreasing levels of total or bioavailable 25-hydroxyvitamin D (P<0.001 for both relationships), yet within each quintile of parathyroid hormone concentration, blacks had significantly lower levels of total 25-hydroxyvitamin D than whites. Among homozygous participants, blacks and whites had similar levels of bioavailable 25-hydroxyvitamin D overall (2.9±0.1 ng per milliliter and 3.1±0.1 ng per milliliter, respectively; P=0.71) and within quintiles of parathyroid hormone concentration.

CONCLUSIONS

Community-dwelling black Americans, as compared with whites, had low levels of total 25-hydroxyvitamin D and vitamin D-binding protein, resulting in similar concentrations of estimated bioavailable 25-hydroxyvitamin D. Racial differences in the prevalence of common genetic polymorphisms provide a likely explanation for this observation. (Funded by the National Institute on Aging and others.).

Predicting vitamin D deficiency in older Australian adults

OBJECTIVE

There has been a dramatic increase in vitamin D testing in Australia in recent years, prompting calls for targeted testing. We sought to develop a model to identify people most at risk of vitamin D deficiency.

DESIGN AND PARTICIPANTS

This is a cross-sectional study of 644 60- to 84-year-old participants, 95% of whom were Caucasian, who took part in a pilot randomized controlled trial of vitamin D supplementation.

MEASUREMENTS

Baseline 25(OH)D was measured using the Diasorin Liaison platform. Vitamin D insufficiency and deficiency were defined using 50 and 25 nmol/l as cut-points, respectively. A questionnaire was used to obtain information on demographic characteristics and lifestyle factors. We used multivariate logistic regression to predict low vitamin D and calculated the net benefit of using the model compared with 'test-all' and 'test-none' strategies.

RESULTS

The mean serum 25(OH)D was 42 (SD 14) nmol/1. Seventy-five per cent of participants were vitamin D insufficient and 10% deficient. Serum 25(OH)D was positively correlated with time outdoors, physical activity, vitamin D intake and ambient UVR, and inversely correlated with age, BMI and poor self-reported health status. These predictors explained approximately 21% of the variance in serum 25(OH)D. The area under the ROC curve predicting vitamin D deficiency was 0·82. Net benefit for the prediction model was higher than that for the 'test-all' strategy at all probability thresholds and higher than the 'test-none' strategy for probabilities up to 60%.

CONCLUSION

Our model could predict vitamin D deficiency with reasonable accuracy, but it needs to be validated in other populations before being implemented.