Vitamin D and bone health in adults with cystic fibrosis

Vitamin D and prebiotics for intestinal health in cystic fibrosis: Rationale and design for a randomized, placebo-controlled, double-blind, 2 x 2 trial of administration of prebiotics and cholecalciferol (vitamin D3) (Pre-D trial) in adults with cystic fibrosis

Individuals with cystic fibrosis (CF) have dysfunctional intestinal microbiota and increased gastrointestinal (GI) inflammation also known as GI dysbiosis. It is hypothesized that administration of high-dose cholecalciferol (vitamin D3) together with a prebiotic (inulin) will be effective, and possibly additive or synergistic, in reducing CF-related GI and airway dysbiosis. Thus, a 2 x 2 factorial design, placebo-controlled, double-blinded, pilot and feasibility, clinical trial was proposed to test this hypothesis. Forty adult participants with CF were block-randomized into one of four groups: 1) high-dose oral vitamin D3 (50,000 IU weekly) plus oral prebiotic placebo daily; 2) oral prebiotic (12 g inulin daily) plus oral placebo vitamin D3 weekly; 3) combined oral vitamin D3 weekly and oral prebiotic inulin daily; and 4) oral vitamin D3 placebo weekly and oral prebiotic placebo. The primary endpoints included 12-week changes in the microbial bacterial communities, gut and airway microbiota richness and diversity before and after the intervention. This pilot study examined whether vitamin D3 with or without prebiotics supplementation was feasible, changed airway and gut microbiota, and reduced dysbiosis, which in turn, may improve health outcomes and quality of life of patients with CF.

Vitamin D deficiency in patients with cystic fibrosis: a systematic review and meta-analysis

AIM

Vitamin D is a prominent modulator of immunity and respiratory function. It plays a vital role in respiratory diseases such as cystic fibrosis (CF). S. However, there is a dearth of information on patients with CF. The purpose of the meta-analysis is to highlight the importance of following the existing guidelines regarding maintenance of Vitamin D serum levels in patients with CF.

METHODS

The systematic search was conducted without utilizing any time or language limitations in original database from the beginning until March 2022. The meta-analysis was performed using a random-effects model. Heterogeneity was determined by I2 statistics and Cochrane Q test.

RESULTS

Pooled analysis using the random-effects model of the 8 case-control studies with 13 effect sizes revealed that the serum 25-OH-vitamin D in participants with cystic fibrosis was significantly lower than controls in pediatrics and adolescences (WMD: - 3.41 ng/ml, 95% CI - 5.02, - 1.80, p =  < 0.001) and adults (WMD: - 2.60 ng/ml, 95% CI - 4.32, - 0.89, p = 0.003). Based on data from 12 studies (21 effect sizes) with a total of 1622 participants, the prevalence of vitamin D levels of 20-30 ng/ml in CF patients was 36% among pediatrics/adolescents and 63% among adults. In addition, 27% of pediatric/adolescent CF patients and 35% of adult CF patients had vitamin D levels of below 20 ng/ml.

CONCLUSIONS

As a result, according to the existing guidelines, our results proved the need to pay attention to the level of vitamin D in these patients.

Vitamin D and Prebiotics for Intestinal Health in Cystic Fibrosis: Rationale and design for a randomized, placebo-controlled, double-blind, 2 × 2 trial of administration of prebiotics and cholecalciferol (vitamin D3) (Pre-D Trial) in adults with cystic fibrosis

Individuals with cystic fibrosis (CF) have dysfunctional intestinal microbiota and increased gastrointestinal (GI) inflammation also known as GI dysbiosis. It is hypothesized that administration of high-dose cholecalciferol (vitamin D3) together with a prebiotic (inulin) will be effective, and possibly additive or synergistic, in reducing CF-related GI dysbiosis and improving intestinal functions. Thus, a 2 × 2 factorial design, placebo-controlled, double-blind, clinical trial was proposed to test this hypothesis. Forty adult participants with CF will be block-randomized into one of four groups: 1) high-dose oral vitamin D3 (50,000 IU weekly) plus oral prebiotic placebo daily; 2) oral prebiotic (12 g inulin daily) plus oral placebo vitamin D3 weekly; 3) combined oral vitamin D3 weekly and oral prebiotic inulin daily; and 4) oral vitamin D3 placebo weekly and oral prebiotic placebo. The primary endpoints will include 12-week changes in the reduced relative abundance of gammaproteobacteria, and gut microbiota richness and diversity before and after the intervention. This clinical study will examine whether vitamin D3 with or without prebiotics will improve intestinal health and reduce GI dysbiosis, which in turn, should improve health outcomes and quality of life of patients with CF.

Changes in bone turnover after high-dose vitamin D supplementation during acute pulmonary exacerbation in cystic fibrosis

In people with cystic fibrosis (CF), chronic inflammation and infection increase the risk for low bone mineral density and CF-related bone disease. During acute pulmonary exacerbations (APE), people with CF have increases in markers of bone resorption. Vitamin D has been proposed as a potential nutrient to lower inflammation. In this ancillary analysis of the Vitamin D for the Immune System in CF study, we hypothesized that vitamin D administered at the time of APE would have favorable changes on bone turnover markers compared to placebo. Participants with CF were randomized to receive a single dose of 250,000 IU of vitamin D or placebo during an APE and followed for 1 year for the primary outcome of APE or death after randomization. Bone turnover markers: C-terminal telopeptide (CTX-1) and procollagen type 1 intact N-terminal propetide (P1NP) were assessed at randomization (during APE) and after recovery from the APE in 45 participants. Participants randomized to vitamin D had significant decreases in markers of bone turnover; participants who received placebo had non-significant increases in markers of bone turnover. Vitamin D supplementation during an APE may help reduce the risk for CF-related bone disease.

The Crosstalk between Vitamin D and Pediatric Digestive Disorders

Vitamin D is a cyclopentane polyhydrophenanthrene compound involved mainly in bone health and calcium metabolism but also autophagy, modulation of the gut microbiota, cell proliferation, immune functions and intestinal barrier integrity. The sources of vitamin D include sunlight, diet and vitamin D supplements. Vitamin D3, the most effective vitamin D isoform is produced in the human epidermis as a result of sunlight exposure. Vitamin D undergoes two hydroxylation reactions in the liver and kidney to reach its active form, 1,25-dihydroxyvitamin D. Recent studies highlighted a complex spectrum of roles regarding the wellbeing of the gastrointestinal tract. Based on its antimicrobial effect, it was recently indicated that vitamin D supplementation in addition to standard eradication therapy might enhance H. pylori eradication rates. Moreover, it was suggested that low levels of vitamin D might also be involved in the acquisition of H. pylori infection. In terms of celiac disease, the negative effects of vitamin D deficiency might begin even during intrauterine life in the setting of maternal deficiency. Moreover, vitamin D is strongly related to the integrity of the gut barrier, which represents the core of the pathophysiology of celiac disease onset, in addition to being correlated with the histological findings of disease severity. The relationship between vitamin D and cystic fibrosis is supported by the involvement of this micronutrient in preserving lung function by clearing airway inflammation and preventing pathogen airway colonization. Moreover, this micronutrient might exert anticatabolic effects in CF patients. Inflammatory bowel disease patients also experience major benefits if they have a sufficient level of circulating vitamin D, proving its involvement in both induction and remission in these patients. The findings regarding the relationship between vitamin D, food allergies, diarrhea and constipation remain controversial, but vitamin D levels should be monitored in these patients in order to avoid hypo- and hypervitaminosis. Further studies are required to fill the remaining gaps in term of the complex impact of vitamin D on gastrointestinal homeostasis.

Trabecular bone score in people with cystic fibrosis

People with cystic fibrosis (CF) are at increased risk of fractures. Our study found that low trabecular bone score (TBS) (a measure of bone strength) may help identify people with CF at risk of fractures especially when combined with bone density measured by DXA, age, hemoglobin A1c, and transplant status.

INTRODUCTION

People with cystic fibrosis (CF) are at increased risk of fractures. This study aims to evaluate the association of trabecular bone score (TBS) with fractures in CF.

METHODS

A cross-sectional study of adults with CF who completed bone density between 2009 and 2019. TBS was applied to lumbar spine studies.

RESULTS

A total of 202 people with CF were included. A history of fracture was present in 36 (17.8%) subjects. Patients with history of fractures had higher hemoglobin A1c (A1C) (7.8 ± 2.7% vs. 6.7 ± 1.7%, p = 0.024), lower femoral neck (FN) Z/T-score (- 1.05 ± 1.08 vs. - 0.44 ± 1.08, p = 0.012), and lower TBS (1.36 ± 0.13 vs. 1.40 ± 0.11, p = 0.05) compared to those without. Lung transplant recipients had a higher prevalence of fractures (50% vs. 14.1%, p < 0.001). The odds ratio (95%CI) of having a fracture for subjects with TBS (≤ 1.2 vs. > 1.2) stratified by FN Z/T-score (≤ - 2.0 or >  - 2.0) was 3.88 (0.92, 16.35), p = 0.07. ROC analysis showed TBS was significantly associated with fractures (p < 0.05); however, FN BMD was superior. A model combining FN BMD, age, A1c, transplant, and TBS improved ROC compared to FN BMD + age (0.837 vs. 0.779, p = 0.031).

CONCLUSIONS

TBS ≤ 1.2 may identify people with CF at high risk of fractures. A model combining FN BMD, age, A1c, transplant, and TBS was significantly associated with fractures compared to FN BMD + age. Future studies are needed to evaluate the prediction of fractures in people with CF using clinical and bone parameters.

Impact of vitamin D status on CF and non-CF bronchiectasis outcomes

Background

Vitamin D deficiency occurs frequently in cystic fibrosis (CF) and non-CF bronchiectasis patients. Yet, few studies have assessed the impact of vitamin D status on the clinical outcomes in pediatric bronchiectasis. This study is designed to assess vitamin D level and determine its effect on exacerbations, bacterial colonization, and lung function in pediatric patients with CF and non-CF bronchiectasis.

Results

This cross-sectional case-control study assessing vitamin D level was performed in a total of sixty cases under the age of 18 years—forty cases with CF and non-CF bronchiectasis and twenty age- and sex-matched healthy controls. Associations between serum vitamin D and clinical and laboratory parameters were assessed in the patient groups. Vitamin D deficiency was more prevalent among CF and non-CF bronchiectasis patients (75%, 45%) compared to controls (10%) (P < 0.001). In addition, vitamin D deficiency was associated with more frequent and severe pulmonary exacerbations (66.7%, 46.7%) (P=0.033, < 0.001), chronic Pseudomonas infection (80%) (P=0.060) among CF patients, and with lower FEV1 (66%) (P= 0.071) among non-CF bronchiectasis. Moreover, a cutoff value of vitamin D level equal or less than 22.5 ng/ml was accurate in differentiating moderate from mild pulmonary exacerbations in both patients’ groups (AUC=0.809) (p=0.004).

Conclusions

Vitamin D deficiency is not uncommon in both CF and non-CF bronchiectasis. In this population, vitamin D deficiency is associated with more frequent pulmonary exacerbations, chronic Pseudomonas infection, and worse lung function.

Vitamin D and its therapeutic relevance in pulmonary diseases

Vitamin D is customarily involved in maintaining bone and calcium homeostasis. However, contemporary studies have identified the implication of vitamin D in several cellular processes including cellular proliferation, differentiation, wound healing, repair and regulatory systems inclusive of host defence, immunity, and inflammation. Multiple studies have indicated corelations between low serum levels of vitamin D, perturbed pulmonary functions and enhanced incidences of inflammatory diseases. Almost all of the pulmonary diseases including acute lung injury, cystic fibrosis, asthma, COPD, Pneumonia and Tuberculosis, all are inflammatory in nature. Studies have displayed strong inter-relations with vitamin D deficiency and progression of lung disorders; however, the underlying mechanism is still unknown. Vitamin D has emerged to possess inhibiting effects on pulmonary inflammation while exaggerating innate immune defenses by strongly influencing functions of inflammatory cells including dendritic cells, monocyte/macrophages, T cells, and B cells along with structural epithelial cells. This review dissects the effects of vitamin D on the inflammatory cells and their therapeutic relevance in pulmonary diseases. Although, the data obtained is very limited and needs further corroboration but presents an exciting area of further research. This is because of its ease of supplementation and development of personalized medicine which could lead us to an effective adjunct and cost-effective method of therapeutic modality for highly fatal pulmonary diseases.

Cystic fibrosis bone disease treatment: Current knowledge and future directions

Bone disease is a frequent complication in adolescents and adults with cystic fibrosis (CF). Early detection and monitoring of bone mineral density and multidisciplinary preventive care are necessary from childhood through adolescence to minimize CF-related bone disease (CFBD) in adult CF patients. Approaches to optimizing bone health include ensuring adequate nutrition, particularly intake of calcium and vitamins D and K, addressing other secondary causes of low bone density such as hypogonadism, encouraging weight bearing exercise, and avoiding bone toxic medications. Of the currently available anti-resorptive or anabolic osteoporosis medications, only bisphosphonates have been studied in individuals with CF. Future studies are needed to better understand the optimal approach for managing CFBD.

Factors Contributing to Vitamin D Status at Hospital Admission for Pulmonary Exacerbation in Adults With Cystic Fibrosis

BACKGROUND

Individuals with cystic fibrosis (CF) have difficulty maintaining optimal vitamin D status due to pancreatic insufficiency-induced malabsorption, inadequate sunlight exposure, and poor intake of vitamin D containing foods. Vitamin D deficiency may increase the risk of pulmonary exacerbations of CF. The objective of this study was to assess factors impacting vitamin D status in patients with CF recently hospitalized for a pulmonary exacerbation of CF.

METHODS

This was a pre-planned analysis of vitamin D intake in patients enrolled in a multi-center, double-blind, randomized controlled study examining vitamin D therapy for pulmonary exacerbation of CF. Demographic information, responses from a habitual sun exposure questionnaire and food frequency questionnaire, and vitamin D supplement usage were queried and compared to serum 25-hydroxyvitamin D (25(OH)D) concentrations.

RESULTS

A total of 48 subjects were included in this analysis. Subjects were taking approximately 1,200 IU of vitamin D daily. Reported vitamin D intake, age, race, employment, and education were not significantly associated with vitamin D status in this population. However, smoking status, sunlight exposure in the last 3 years, and skin type (in the bivariate model) were all significantly associated with vitamin D status (all p<0.05).

CONCLUSIONS

Sunlight exposure was the most predictive determinant of vitamin D status in patients with CF prior to pulmonary exacerbation. Subjects reported vitamin D intake below the recommended amounts. The role and mode of optimizing vitamin D status prior to a pulmonary exacerbation needs further investigation.

Prevention of osteoporosis in cystic fibrosis

PURPOSE OF REVIEW

The increased life span of patients with cystic fibrosis has lead to the detection of new complications. Osteopenia is present in up to 50% of adult patients with cystic fibrosis, and osteoporosis in 10-34% and can cause a difficult management problem.

RECENT FINDINGS

In children, defects in bone health become apparent generally at adolescence because of suboptimall bone peak mass achievement. Malnutrition, inflammation, vitamin D and vitamin K deficiency, altered sex hormone production, glucocorticoid therapy, and physical inactivity potentiate poor bone health.

SUMMARY

Monitoring bone mineral density and preventive care of osteoporosis are necessary from childhood to minimize cystic fibrosis-related bone disease in adult cystic fibrosis patients.

Relationship Between Estrogen Treatment and Skeletal Health in Women With Cystic Fibrosis

BACKGROUND

Patients with cystic fibrosis (CF) are at risk for CF-related bone disease. Women with CF may use estrogen supplementation for reasons other than skeletal health. It is unknown whether estrogen therapy has a beneficial impact on skeletal health in women with CF.

METHODS

In this retrospective cohort study of women with CF followed at a single CF center, the lumbar spine bone mineral density (BMD) of women with CF exposed to supplemental and not exposed to supplemental estrogen were compared. Spline function models included the main effect of estrogen exposure and the interaction between age and estrogen supplementation.

RESULTS

Of the 145 subjects analyzed, 44 subjects were exposed to supplemental estrogen. The baseline characteristics of estrogen exposed and unexposed subjects were similar except for use of CF transmembrane conductance regulator modulators and anti-osteoporosis medications. Women exposed to estrogen reached peak BMD around 21 years of age, but women not exposed to estrogen reached peak BMD around 25 years of age. A significant interaction of age and estrogen supplementation indicated that the lumbar spine BMD trajectories differed by exposure group.

CONCLUSIONS

Our study demonstrates that few women with CF of reproductive age are prescribed estrogen therapy. Furthermore, estrogen exposure up to age 21 is associated with improved BMD, but estrogen exposure after age 21 does not appear to be associated with improved BMD. Further studies are needed to understand the reasons for the low rates of estrogen use in young women with CF and the optimal timing, dose and formulation of estrogen prescription.

Vitamin D Deficiency and Radiological Findings in Adult Non-Cystic Fibrosis Bronchiectasis

OBJECTIVES

Vitamin D may play an important role in immunity and its deficiency has been related to increased respiratory infections. The aim of this study was to detect the prevalence of vitamin D deficiency and to investigate the relationship between radiological and clinical effects on adult bronchiectasis (BR) patients.

MATERIALS AND METHODS

A total of 130 patients with BR and 73 healthy individuals (control group) were enrolled in this study. Radiological severity was assessed using Modified Reiff Score.

RESULTS

The mean age of patients was 41.9±9.1 years (range, 18-85). The mean 25-hydroxyvitamin D (25(OH)D) level was 14.7±9.6 ng/mL in BR patients and 19.8±6.9 ng/mL in the control group (p=0.001). Moreover, 95 (73.1%) adult BR patients were categorized as vitamin D deficient. Patients in the vitamin D deficiency group had significantly higher Modified Medical Research Council scores than those in the group without vitamin D deficiency (p=0.036) The mean modified Reiff score was higher in the vitamin D deficient group than the without vitamin D deficiency group (6.9±3.8 vs 4.9± 2.7, p=0.001). Additionally, the vitamin D deficient group had lower forced vital capacity% predicted value (p=0.02). This model showed that Reiff score (OR, 1.285[1.039-1.590]; p=0.021) was independently related to vitamin D deficiency.

CONCLUSION

We found that vitamin D deficiency is commonly seen in adult BR patients in a stable period. Moreover, it might be related to severe radiological findings on chest computed tomography and worse lung functions.

Targeting Vitamin D Deficiency to Limit Exacerbations in Respiratory Diseases: Utopia or Strategy With Potential?

Patients with respiratory diseases such as cystic fibrosis, chronic obstructive pulmonary disease, or asthma often experience an acute worsening of respiratory symptoms, termed exacerbations. Although the course of exacerbations is disease specific, they are mostly triggered by a respiratory infection. Exacerbations often require hospitalization and are an important cause of mortality. Treatments of exacerbations aim to minimize the negative impact and to prevent subsequent events. Despite many existing therapy options, many patients do not benefit from therapy and suffer from recurrent events. Vitamin D deficiency is a worldwide problem and is extremely prevalent in these patients. Vitamin D, known for its calcemic effects, also has immunomodulatory and anti-infectious actions and can therefore be a possible agent to treat or prevent exacerbations. This review will focus on vitamin D as a potential candidate to treat or prevent exacerbations in CF, COPD, and asthma.

Dynamic regression with recurrent events

Recurrent events often arise in follow-up studies where a subject may experience multiple occurrences of the same event. Most regression models with recurrent events tacitly assume constant effects of covariates over time, which may not be realistic in practice. To address time-varying effects, we develop a dynamic regression model to target the mean frequency of recurrent events. We propose an estimation procedure which fully exploits observed data. Consistency and weak convergence of the proposed estimator are established. Simulation studies demonstrate that the proposed method works well, and two real data analyses are presented for illustration.

Vitamin D for the Immune System in Cystic Fibrosis (DISC): a double-blind, multicenter, randomized, placebo-controlled clinical trial

BACKGROUND

Patients with cystic fibrosis (CF) have increased risk of vitamin D deficiency owing to fat malabsorption and other factors. Vitamin D deficiency has been associated with increased risk of pulmonary exacerbations of CF.

OBJECTIVES

The primary objective of this study was to examine the impact of a single high-dose bolus of vitamin D3 followed by maintenance treatment given to adults with CF during an acute pulmonary exacerbation on future recurrence of pulmonary exacerbations.

METHODS

This was a multicenter, double-blind, placebo-controlled, intent-to-treat clinical trial. Subjects with CF were randomly assigned to oral vitamin D3 given as a single dose of 250,000 International Units (IU) or to placebo within 72 h of hospital admission for an acute pulmonary exacerbation, followed by 50,000 IU of vitamin D3 or an identically matched placebo pill taken orally every other week starting at 3 mo after random assignment. The primary outcome was the composite endpoint of the time to next pulmonary exacerbation or death within 1 y. The secondary outcomes included circulating concentrations of the antimicrobial peptide cathelicidin and recovery of lung function as assessed by the percentage of predicted forced expiratory volume in 1 s (FEV1%).

RESULTS

A total of 91 subjects were enrolled in the study. There were no differences between the vitamin D3 and placebo groups in time to next pulmonary exacerbation or death at 1 y. In addition, there were no differences in serial recovery of lung function after pulmonary exacerbation by FEV1% or in serial concentrations of plasma cathelicidin.

CONCLUSIONS

Vitamin D3 initially given at the time of pulmonary exacerbation of CF did not alter the time to the next pulmonary exacerbation, 12-mo mortality, serial lung function, or serial plasma cathelicidin concentrations. This trial was registered at clinicaltrials.gov as NCT01426256.

Updates in vitamin D therapy in cystic fibrosis

PURPOSE OF REVIEW

To summarize recent developments the role of vitamin D and treatment of vitamin D deficiency in cystic fibrosis.

RECENT FINDINGS

Although treatment of low vitamin D levels continues to be important for optimizing bone health in cystic fibrosis, increasing data on the extraskeletal effects of vitamin D are becoming available. Exploratory studies of vitamin D in modulation of respiratory and intestinal microbiomes, and the influence of vitamin D on the metabolomic signature of cystic fibrosis, suggest expanded roles for vitamin D in cystic fibrosis disease and treatment.

SUMMARY

Emerging developments in cystic fibrosis regarding therapeutics and effects of vitamin D on bone health, inflammation, microbiome, and the metabolome are summarized.

Vitamin D deficiency in sickle cell disease patients in the Eastern Province of Saudi Arabia

BACKGROUND

Vitamin D deficiency (VDD) is a major global health problem. In sickle cell disease (SCD), VDD is highly prevalent, reaching up to 96% of populations. VDD may contribute to many of the complications of SCD.

OBJECTIVE

Estimate the 25-hydroxyvitamin D [25(OH)D] level and the frequency of VDD and insufficiency among among SCD patients by age group and disease status.

DESIGN

Analytical cross-sectional.

SETTING

Ministry of Health (MOH) secondary care hospital.

PATIENTS AND METHODS

Non-probability purposive sampling was used to select SCD patients, aged 12 years and older, of both sexes, who had visited the hospital during a period of 5 years (2010-2014). Blood samples were processed by electrochemiluminescence technology.

MAIN OUTCOME MEASURE(S)

25(OH)D levels by demographic data, and disease activity.

SAMPLE SIZE

640 patients.

RESULTS

Of those, 82% (n=523) had suboptimal 25(OH)D (0-<30 ng/ mL), and 67% were deficient (0-<20 ng/mL). Patients with any SCD crisis (20.7%, 144/694) had lower 25(OH)D (median, IQR: 10.1 ng/mL [8.6] ng/mL) compared to patients without crisis (71.0%, 493/694) (15.7 ng/ mL [18.2] ng/mL) (P<.001). Deficiency was more common in the young.er age groups and in sickle cell anemia patients with crisis.

CONCLUSIONS

VDD is highly prevalent in this population. Established vitamin D screening is a necessity, so that affected patients can be treated.

LIMITATIONS

Presence of residual confounders such as nutritional status, physical activity, lack of sun exposure, medications that alleviate SCD crises (such as hydroxyurea), and comorbid illnesses. The relationship between sickle cell disease genotype and vitamin D level was not analyzed.

CONFLICT OF INTEREST

None.

Osteoporosis Is Associated with Deteriorating Clinical Status in Adults with Cystic Fibrosis

BACKGROUND

Cystic fibrosis (CF) patients are in increased risk of osteoporosis. We aimed to determine the osteoporosis prevalence in an adult CF cohort and investigate calcium metabolic parameters and clinical status' association with bone mineral density evaluated by dual X-ray absorptiometry scan.

METHODS

We performed a cross section database study of adults at a tertiary CF Center. Z scores were applied for patients < 50 years of age and T scores for patients > 50 years of age.

RESULTS

One hundred twenty-five patients were included. Compared to nonosteoporotic patients, osteoporotic patients (15%) had significantly lower percent predicted forced expiratory volume in 1 second (ppFEV1), lower body mass index, higher frequency of CF-related diabetes and chronic lung infection, and higher high-sensitive C-reactive protein and glycated hemoglobin levels. Vitamin D was not associated with any outcome. In multivariate analyses, only ppFEV1 and female gender were independently associated with Z scores.

CONCLUSIONS

Osteoporosis in CF occurs with deteriorating clinical status while the role of calcium metabolism seems minor. Gender specific and dysglycemic impact on bone status should be investigated further.

Vitamin D and the lung

Vitamin D metabolism is complex and its deficiency has proven to be deleterious in bone health, and to have significant effects on the immune and cardiovascular systems. Vitamin D has also been associated with pulmonary diseases outcomes. This review will focus on vitamin D metabolism, and studies performed mostly in children with asthma or Cystic Fibrosis.

Vitamin D deficiency and clinical correlations in systemic sclerosis patients: A retrospective analysis for possible future developments

Objective

Assessment of serum 25-hydroxyvitamin D (25(OH)D) correlations with clinical parameters and evaluation of the efficacy of standard oral supplementation in systemic sclerosis (SSc) patients.

Methods

154 SSc patients were recruited, in all seasons. Serum 25(OH)D concentrations were evaluated using LIAISON 25-OH (Diasorin, Italy). Medsger disease severity scale (DSS), nailfold videocapillaroscopy (NVC) and all instrumental exam contemplated by international guidelines were performed. Drug assumption, including oral colecalciferol, was evaluated. Non-parametric tests were used for statistical analysis.

Results

Average 25(OH)D serum concentration was 18.7 ±9 ng/ml (<20 classified as deficiency). A significant correlation was found with presence/absence of lung bi-basal fibrotic changes (16.1 ±8 ng/ml and 20 ±10 ng/ml, respectively; p = 0.04). Peripheral vascular (p = 0.03), kidney (p = 0.02), gastrointestinal (p = 0.05) Medsger’s DSS parameters were found to correlate with 25(OH)D serum concentrations. No significant correlations were observed with digital ulcers incidence, strictly correlated to patterns of microangiopathy, defined at NVC analysis (p<0.0001). Interestingly, no effects of treatment with oral colecalciferol (Dibase 1,000 IU daily for at least 6 months) were found on 25(OH)D serum concentrations in treated (18.8 ±10 ng/ml) or untreated (18.7 ±9 ng/ml) SSc patients (p = 0.81). A significant difference was observed among seasonal 25(OH)D serum concentrations (winter: 14.6 ±7.8 ng/ml, spring: 17.2 ±7.9 ng/ml, summer: 21.43 ±10 ng/ml, autumn: 20.2 ±10 ng/ml; p = 0.032) in all patients.

Conclusion

Serum 25(OH)D deficiency was found to correlate with lung involvement, peripheral vascular, kidney and gastrointestinal Medsger’s DSS parameters and with seasonality In SSc patients. Supplementation with oral colecalciferol was found not effective in increasing 25(OH)D serum concentrations. Therefore, for successful replacement, supra-physiological vitamin D3 doses or programmed UVB light exposure should be tested.

The Vitamin D for Enhancing the Immune System in Cystic Fibrosis (DISC) trial: Rationale and design of a multi-center, double-blind, placebo-controlled trial of high dose bolus administration of vitamin D3 during acute pulmonary exacerbation of cystic fibrosis

Vitamin D deficiency is highly prevalent in children and adults with cystic fibrosis (CF). Recent studies have found an association between vitamin D status and risk of pulmonary exacerbations in children and adults with CF. The ongoing Vitamin D for enhancing the Immune System in Cystic fibrosis (DISC) study is a multi-center, double-blind, randomized, placebo-controlled trial that will test the hypothesis of whether high dose vitamin D given as a single oral bolus of 250,000 IU to adults with CF during a pulmonary exacerbation followed by a maintenance dose of vitamin D will improve time to next pulmonary exacerbation and re-hospitalization, improve survival and lung function compared to placebo and reduce the rates of pulmonary exacerbation,. Subjects will be randomized 1:1 at each clinical site to vitamin D or placebo within 72 hours of hospital admission for pulmonary exacerbation. Clinical follow-up visits will occur at 1, 2, 3, and 7 days, and 1, 3, 6 and 12 months after randomization. Blood and sputum will be collected and determination of clinical outcomes will be assessed at each visit. The primary endpoint will be the time to next pulmonary exacerbation requiring antibiotics, re-hospitalization or death. The secondary endpoints will include lung function assessed by forced expiratory volume in 1 second (FEV1), blood markers of inflammatory cytokines, anti-microbial peptide expression by peripheral blood mononuclear cells and circulating concentrations in blood. Other exploratory endpoints will examine the phenotype of neutrophils and monocyte/macrophages in sputum. Nutritional status will be assessed by 3 day food records and food frequency questionnaire.

Accrual of Bone Mass in Children and Adolescents With Cystic Fibrosis

CONTEXT

Low bone density is a complication of cystic fibrosis (CF).

HYPOTHESIS

Accrual of bone mass is most impaired in the sickest children, as judged by nutritional status and pulmonary function.

DESIGN

Retrospective analysis of correlation between lumbar spine bone mineral density (BMD), body mass index (BMI), and forced expiratory volume in 1 second (FEV1) z scores in children and adolescents with CF.

SETTING

Pediatric hospital specialist CF service.

PATIENTS

Sixty participants aged 5.9 to 18.8 years (24 female) with confirmed CF.

INTERVENTIONS

Lumbar spine BMD, BMI, and FEV1 z scores measured at first BMD scan; 40 participants had sequential scans. Change in L1-L4 z scores over time was used as a measure of bone accrual, and BMI as a measure of nutritional status.

OUTCOME MEASURES

Correlations between lumbar spine BMD, BMI, and FEV1 z scores.

RESULTS

Mean BMI and BMD z scores were strongly correlated at the initial scan (P < 0.0001), suggesting that nutritional status is a major determinant of BMD. In the sequential scan at a mean age of 16.1 years, height centile was maintained, indicating normal linear growth. Changes in BMI and BMD z scores were positively correlated (P = 0.001), indicating that patients failing to gain weight appropriately with growth were also failing to acquire bone normally. Change in FEV1 z score was correlated with change in both BMD (P < 0.0001) and BMI z scores (P = 0.02).

CONCLUSION

Although young people with CF may be maintaining normal growth in height, bone accrual is impaired in those with the poorest nutritional status and lung function.

Plasma metabolomics in adults with cystic fibrosis during a pulmonary exacerbation: A pilot randomized study of high-dose vitamin D3 administration

BACKGROUND

Cystic fibrosis (CF) is a chronic catabolic disease often requiring hospitalization for acute episodes of worsening pulmonary exacerbations. Limited data suggest that vitamin D may have beneficial clinical effects, but the impact of vitamin D on systemic metabolism in this setting is unknown.

OBJECTIVE

We used high-resolution metabolomics (HRM) to assess the impact of baseline vitamin D status and high-dose vitamin D₃ administration on systemic metabolism in adults with CF with an acute pulmonary exacerbation.

DESIGN

Twenty-five hospitalized adults with CF were enrolled in a randomized trial of high-dose vitamin D₃ (250,000IU vitamin D₃ bolus) versus placebo. Age-matched healthy subjects served as a reference group for baseline comparisons. Plasma was analyzed with liquid chromatography/ultra-high resolution mass spectrometry. Using recent HRM bioinformatics and metabolic pathway enrichment methods, we examined associations with baseline vitamin D status (sufficient vs. deficient per serum 25-hydroxyvitamin D concentrations) and the 7-day response to vitamin D₃ supplementation.

RESULTS

Several amino acids and lipid metabolites differed between CF and healthy control subjects, indicative of an overall catabolic state. In CF subjects, 343 metabolites differed (P<0.05) by baseline vitamin D status and were enriched within 7 metabolic pathways including fatty acid, amino acid, and carbohydrate metabolism. A total of 316 metabolites, which showed enrichment for 15 metabolic pathways-predominantly representing amino acid pathways-differed between the vitamin D₃- and placebo-treated CF subjects over time (P<0.05). In the placebo group, several tricarboxylic acid cycle intermediates increased while several amino acid-related metabolites decreased; in contrast, little change in these metabolites occurred with vitamin D₃ treatment.

CONCLUSIONS

Numerous metabolic pathways detected by HRM varied in association with vitamin D status and high-dose vitamin D₃ supplementation in adults with CF experiencing a pulmonary exacerbation. Overall, these pilot data suggest an anti-catabolic effect of high-dose vitamin D₃ in this clinical setting.

Treatment of vitamin D deficiency in cystic fibrosis

Vitamin D deficiency occurs frequently in patients with cystic fibrosis (CF). Vitamin D is important for optimal mineralization of bone and may be important for other comorbidities commonly occurring in patients with CF. Vitamin D deficiency in patients with CF can arise from various causes including pancreatic exocrine insufficiency, lack of outdoor activity, and alterations of vitamin D metabolism. Due to fat malabsorption stemming from pancreatic insufficiency, higher oral doses of vitamin D are necessary to correct and maintain optimal vitamin D status in patients with CF. Recent studies have demonstrated that higher vitamin D status is associated with better lung function and that vitamin D therapy may help recovery from pulmonary exacerbations of CF. The mechanisms by which vitamin D may exert its beneficial actions in CF are unclear but likely related to the role vitamin D has in modulating the adaptive and innate immune response. Large randomized clinical studies to evaluate the potential role of vitamin D as adjunctive therapy in CF that goes beyond bone are necessary.

Vitamin D3 supplementation among adult patients with cystic fibrosis

BACKGROUND & AIMS

Vitamin D (Vit D) deficiency in cystic fibrosis (CF) is partially secondary to exocrine pancreatic insufficiency. Our aim was to establish a Vit D₃ supplementation protocol that will increase 25(OH)D to the recommended level (30 ng/mL).

METHODS

Retrospective study of 200 patients (≥18 years) conducted from February 2007 to June 2014 at the CF clinic of the Centre Hospitalier de l'Université de Montréal. Vit D₃ supplementation protocol was 1600 IU/day or 10,000 IU/week during the summer (May 1st to October 31st) and 3200 IU/day or 20,000 IU/week during the winter (November 1st to April 30th), in addition to the 1200 IU/day included in multivitamins.

RESULTS

Significant increase in serum 25(OH)D levels from baseline (25.9 ± 10.3 ng/mL) to follow-up (37.0 ± 11.4 ng/mL) (P ≤ 0.001). At follow-up, increased doses during the winter improved serum 25(OH)D levels to a degree comparable to the summer.

CONCLUSIONS

This supplementation protocol is efficient and needs to be tested in other CF adult cohorts and correlated to potential health benefit measurements.

Large, single-dose, oral vitamin D supplementation in adult populations: a systematic review

OBJECTIVE

Daily vitamin D supplementation is often inadequate in treating vitamin D deficiency due to poor compliance. A single, large dose of vitamin D given at timed intervals may be an alternative strategy.

METHODS

We conducted a systematic literature review to investigate the efficacy of a single large bolus dose to treat vitamin D deficiency. We identified 2,243 articles in PubMed using the terms "high dose vitamin D," "single dose vitamin D," "bolus vitamin D," or "annual dose vitamin D." Review articles, cross-sectional studies, non-human studies, responses to other articles, and non-English articles were excluded. Manuscripts were also excluded if the study: (1) did not use oral cholecalciferol or ergocalciferol, (2) used vitamin D analogs, (3) enrolled participants under age 18 years, (4) administered doses <100,000 international units (IU) (2.5 mg), or (5) administered >1 dose per year. References of eligible manuscripts and the Cochrane databases were also searched. Two independent reviewers identified eligible manuscripts, and a third reviewer evaluated disagreements. Thirty manuscripts were selected using these criteria.

RESULTS

Large, single doses of vitamin D consistently increased serum/plasma 25-hydroxyvitamin D (25[OH]D) concentrations in several vitamin D-sufficient and -deficient populations. Vitamin D3 doses ≥300,000 IU provided optimal changes in serum/plasma 25(OH)D and parathyroid hormone (PTH) concentrations. Vitamin D supplementation also impacted bone health and extraskeletal endpoints.

CONCLUSION

This review recommends that vitamin D3 be used for supplementation over vitamin D2 and concludes that single vitamin D3 doses ≥300,000 IU are most effective at improving vitamin D status and suppressing PTH concentrations for up to 3 months. Lower doses, however, may be sufficient in certain populations. Vitamin D doses >500,000 IU should be used judiciously in order to minimize adverse events.

Endocrine Disorders in Cystic Fibrosis

Cystic fibrosis is frequently complicated by endocrine disorders. Diabetes can be expected to affect most with CF and pancreatic insufficiency and varies widely in age of onset, but early identification and treatment improve morbidity and mortality. Short stature can be exacerbated by relative delay of puberty and by use of inhaled corticosteroids. Bone disease in CF causes fragility fractures and should be assessed by monitoring bone mineral density and optimizing vitamin D status. Detecting and managing endocrine complications in CF can reduce morbidity and mortality in CF. These complications can be expected to become more common as the CF population ages.

Bone health and disease in cystic fibrosis

Low bone mineral density is common in children and adults with CF. It has a multifactorial aetiology that includes direct effects of CFTR dysfunction on bone cell activity, as well as the secondary effects of CFTR dysfunction including pancreatic insufficiency (leading to malnutrition/malabsorption of fat soluble vitamins) and pulmonary infection (leading to systemic inflammation and increased bone resorption). Strategies to improve bone health in CF include optimising general CF nutritional and pulmonary care and the judicious use of bisphosphonates in selected patients. CFTR correctors/potentiators may have positive impact on bone metabolism in people with CF.

Prospective, Randomized, Double-Blind, Parallel-Group, Comparative Effectiveness Clinical Trial Comparing a Powder Vehicle Compound of Vitamin D With an Oil Vehicle Compound in Adults With Cystic Fibrosis

BACKGROUND

There is little consensus on the most efficacious vehicle substance for vitamin D supplements. Fat malabsorption may impede the ability of patients with cystic fibrosis (CF) to absorb vitamin D in an oil vehicle. We hypothesized that vitamin D contained in a powder vehicle would be absorbed more efficiently than vitamin D contained in an oil vehicle in patients with CF.

METHODS

In this double-blind, randomized controlled trial, hospitalized adults with CF were given a one-time bolus dose of 100,000 IU of cholecalciferol (D₃) in a powder-based or oil-based vehicle. Serum D₃, 25-hydroxyvitamin D, and parathyroid hormone concentrations were analyzed at 0, 12, 24, and 48 hours posttreatment. The area under the curve for serum D₃ and the 12-hour time point were also assessed as indicators of D₃ absorption.

RESULTS

This trial was completed by 15 patients with CF. The median (interquartile range) age, body mass index, and forced expiratory volume in 1 second were 23.7 (19.9-33.2) years, 19.9 (18.6-22.6) kg/m², and 63% (37%-80%), respectively. The increase in serum D₃ and the area under the curve was greater in the powder group ( P = .002 and P = .036, respectively). Serum D₃ was higher at 12 hours in the powder group compared with the oil group ( P = .002), although levels were similar between groups by 48 hours.

CONCLUSIONS

In adults with CF, cholecalciferol is more efficiently absorbed in a powder compared with an oil vehicle. Physicians should consider prescribing vitamin D in a powder vehicle in patients with CF to improve the absorption of vitamin D from supplements.

Free 25-Hydroxyvitamin D Concentrations in Cystic Fibrosis

BACKGROUND

Vitamin D deficiency is common in cystic fibrosis (CF), but there is no previous data on free 25-hydroxyvitamin D (25[OH]D) in CF or in relation to healthy individuals.

METHODS

We assessed total serum 25(OH)D concentration by chemiluminescence and serum free 25(OH)D concentration by both direct measurement (ELISA) and calculation, using serum albumin and vitamin D binding protein (VDBP) levels in 80 subjects (28 healthy adults, 25 clinically stable adults and children with CF and 27 adults experiencing a CF exacerbation).

RESULTS

Serum albumin and VDBP concentrations were lower in CF compared with healthy controls. Total serum 25(OH)D concentrations were positively correlated with both calculated and measured free 25(OH)D (P < 0.001 for both). Calculated and directly measured serum free 25(OH)D levels were positively correlated (P < 0.001).

CONCLUSIONS

Serum levels of directly measured free 25(OH)D positively correlated with total 25(OH)D, suggesting that achieving sufficient total serum 25(OH)D may result in adequate free 25(OH)D levels in CF.

Vitamin D deficiency in patients with intestinal malabsorption syndromes--think in and outside the gut

There is a very high prevalence of vitamin D deficiency, which is defined by a serum level of 25-hydroxyvitamin D [25(OH)D] of lower than 20 ng/mL, in all populations of the world. Unfortunately, the prevalence of vitamin D deficiency in patients with intestinal malabsorption syndromes, including cystic fibrosis (CF), celiac disease (CD), short bowel syndrome and inflammatory bowel disease (IBD), is higher than that in the general population, indicating the presence of disease-specific causative factors. In this review, we aimed to present clinical findings to highlight the roles of insufficient exposure to sunlight and inflammation in the development of vitamin D deficiency in patients with intestinal malabsorption syndromes. Furthermore, we aimed to present experimental evidence that supported a role of vitamin D deficiency in the pathogenesis of IBD. Finally, we reviewed clinical intervention strategies aiming to normalize vitamin D status in and even to improve the conditions of patients and to discuss certain issues that needed to be addressed in future research.

A randomized controlled trial of vitamin D replacement strategies in pediatric CF patients

BACKGROUND

Vitamin D insufficiency is common in children with cystic fibrosis (CF), yet data are sparse regarding the most effective form of vitamin D supplementation. The aim of this study was to compare two different vitamin D replacement regimens.

METHODS

We conducted a randomized controlled trial comparing 50,000 IU of ergocalciferol (vitamin D2) twice weekly for 8 weeks versus 50,000 IU of cholecalciferol (vitamin D3) weekly in patients with CF, pancreatic insufficiency, age 6-21 years and a 25(OH)D<30 ng/mL. The primary outcome was change in serum 25(OH)D concentration. For secondary analyses, we examined changes in IgG, IgE and CRP in patients who normalized their vitamin D levels.

RESULTS

A total of 47 patients completed the trial. The mean pre-treatment 25(OH)D concentration was 23.1 (SD 4.7) ng/mL. The overall mean increase in 25(OH)D was 11.1 (11.9) ng/mL and 31/47 (66%) achieved a 25(OH)D concentration ≥ 30 ng/mL; of the 26 participants who received D2, 18 (69%) achieved sufficiency while 13/21 (62%) participants treated with D3 achieved sufficiency. There was no difference between groups in change of 25(OH)D (p=0.65). Similarly, there was no difference in the number of patients to achieve vitamin D sufficiency between treatments (p=0.6).

CONCLUSIONS

Ergocalciferol administered as 50,000 IU twice weekly is as effective as cholecalciferol 50,000 IU weekly for 8 weeks in pediatric patients with CF and vitamin D insufficiency. Only 66% of the patients studied achieved the desired 25(OH)D concentration.

Clinical, anthropometric and laboratory nutritional markers of pancreatic exocrine insufficiency: Prevalence and diagnostic use

Pancreatic exocrine insufficiency (PEI) frequently occurs secondary to exocrine pancreatic disease (e.g. chronic pancreatitis, cystic fibrosis, cancer) or pancreatic/gastrointestinal surgery, resulting in the maldigestion of nutrients and consequently malnutrition. Pancreatic enzyme replacement therapy (PERT) is the cornerstone of PEI management. Despite its clinical relevance, the diagnosis of PEI in clinical practice is challenging, as the current gold standard test is cumbersome, and alternatives have limited availability or accuracy. There is a need for accurate and easily applicable diagnostic modalities. We review the prevalence of clinical symptoms and changes in anthropometric measurements and laboratory nutritional markers indicative of malnutrition in patients with PEI, and the relevance of these findings in diagnosing PEI and monitoring PERT efficacy. Based on limited available evidence, assessment of clinical symptoms, body weight, body mass index and other anthropometric parameters are not sensitive methods for PEI diagnosis, owing to high variability and multiple confounding factors, but appear useful in monitoring PERT efficacy. Limited evidence precludes strong recommendations but suggests that serum levels of vitamin E, magnesium, and plasma proteins, notably retinol binding protein, albumin, and prealbumin, may have diagnostic utility in PEI. Studies show that assessment of changes in these and other nutritional parameters is helpful in monitoring PERT efficacy. Further research is needed to confirm the diagnostic accuracy of these parameters for PEI. Until such data are available, a nutritional evaluation including circulating vitamin E, magnesium, retinol binding protein, albumin, and prealbumin may be used to evaluate the probability of PEI in clinical practice when reliable pancreatic function tests are not available.

Impact of vitamin D on infectious disease

BACKGROUND

Observational studies have linked vitamin D status and infectious disease. This association is supported by the presence of the vitamin D receptor and CYP27B1 in immune cells. This review aims to consolidate data from clinical trials that used vitamin D for the treatment or prevention of infectious disease.

METHODS

The authors searched the term "(vitamin D OR ergocalciferol OR cholecalciferol OR vitamin D2 OR vitamin D3 OR calcitriol) AND (infection OR tuberculosis OR sepsis OR pneumonia)" with limits preset to manuscripts published in English and with human subjects. They identified controlled trials that measured infectious outcomes (eg, incidence and severity of disease, time to disease resolution or recurrence, measures of clinical improvement, mortality). Studies that used analog, topical or micronutrient formulations of vitamin D, assessed only vitamin D status or lacked a comparison group were excluded. The references from eligible manuscripts and from 2 recent reviews were scanned for additional manuscripts.

RESULTS

One thousand two hundred eighty-four manuscripts were identified with our search terms, with 60 papers still eligible after review of the title and abstract. Full review of these papers, their references and 2 related reviews yielded 38 manuscripts.

CONCLUSIONS

Although some prospective studies show positive results regarding vitamin D on infectious disease, several robust studies are negative. Factors such as high variability between studies, the difference in individual responsiveness to vitamin D and study designs that do not primarily investigate infectious outcomes may mask the effects of vitamin D on infections.

Association between serum 25-hydroxyvitamin D level and pulmonary exacerbations in cystic fibrosis

OBJECTIVE

To identify effects of vitamin D status, as defined by circulating 25-hydroxyvitamin D (25-OHD) levels on the annual frequency of pulmonary exacerbations (Pex) and hospitalizations, on standard measures of pulmonary function, and to identify determinants of 25-OHD levels in pediatric patients with cystic fibrosis (CF).

HYPOTHESIS

Higher levels of serum 25-OHD would be associated with fewer Pex and hospitalizations, and improved lung function based on pulmonary function tests (PFTs).

STUDY DESIGN

Retrospective chart review of 53 pediatric patients from January 2011 to December 2011. Significant relationships were examined using linear and logistic regression analyses.

PATIENT SELECTION

Patients ages 5 through 22 years followed at the CF Care Center and Clinic at Yale-New Haven Hospital, New Haven, CT., who had at least four clinic visits and at least one 25-OHD measurement between January 1, 2011 and December 31, 2011.

RESULTS

Serum 25-OHD level and gender were strong independent determinants of the annual number of Pex (P < 0.01, with lower 25-OHD level and female gender associated with Pex). There was a significant influence of gender (P < 0.05) and a near-significant influence of serum 25-OHD (P < 0.08) on hospitalization rate. There was no effect of 25-OHD levels on PFTs. Other candidate factors (age, season, gender, pancreatic sufficiency, or severity of genetic mutation) did not significantly effect 25-OHD level.

CONCLUSIONS

The annual number of Pex in pediatric CF patients is significantly associated with 25-OHD levels and gender, raising the consideration that maintaining vitamin D sufficiency may lead to decreased incidence of Pex and hospitalizations requiring antibiotic therapy.

Vitamin D status in children with cystic fibrosis. Associations with inflammation and bacterial colonization

RATIONALE

Patients with cystic fibrosis (CF) have high rates of vitamin D insufficiency. The relation between vitamin D status and inflammation in patients with CF is poorly understood.

OBJECTIVES

To determine the prevalence of vitamin D deficiency and insufficiency in a young CF population and to examine correlations between vitamin D status, disease severity, and inflammatory markers.

METHODS

This was a retrospective chart review of patients with CF under the age of 12 years. Serum laboratory parameters, growth indices, pancreatic status, CFTR genetics, medications, microbiology, and presence of CF-related comorbidities were collected for patients who had fat-soluble vitamin levels measured between January 1, 2009 and December 31, 2011. Vitamin D deficiency was defined as a serum 25(OH)D less than 20 ng/ml and insufficiency as serum 25(OH)D 20 to 29.9 ng/ml. Associations between serum vitamin D concentration and clinical/inflammatory markers were assessed using Chi-square and t tests.

MEASUREMENTS AND MAIN RESULTS

Data were collected for 148 children. The mean serum 25(OH)D concentration was 32.4 ng/ml (SD, 8.9). Seven percent (10 of 148) were vitamin D deficient, and 36% (53 of 148) were vitamin D insufficient. Among the pancreatic-sufficient patients, 50% (14 of 28) were vitamin D insufficient/deficient, whereas among pancreatic-insufficient patients, 41% (49 of 120) were vitamin D insufficient/deficient. Pseudomonas aeruginosa was a more common pathogen in the patients who were vitamin D insufficient/deficient (18 of 63 vs. 11 of 85, P = 0.018). There was no difference between vitamin D-sufficient versus -insufficient groups in terms of other bacterial colonization or inflammatory markers.

CONCLUSIONS

Overall, vitamin D insufficiency is common among young children with CF. Vitamin D insufficiency is prevalent even in children who are pancreatic sufficient. In this population, vitamin D insufficiency is associated with a history of Pseudomonas colonization but not with classic markers of systemic inflammation.

Vitamin D deficiency is associated with pulmonary exacerbations in children with cystic fibrosis

RATIONALE

Recent literature suggests vitamin D has an effect on lung function and on the lung's ability to fight infection, both important in the cystic fibrosis (CF) population as predictors of morbidity and mortality.

OBJECTIVES

Our study assessed associations between vitamin D and % predicted lung function, pulmonary exacerbations, and first Pseudomonas aeruginosa infection in children with CF. We hypothesized that children with CF who have 25-hydroxy vitamin D (25-OHD) levels less than 30 μg/L would have lower % predicted lung function and more pulmonary exacerbations than those with 25-OHD greater than or equal to 30 μg/L.

METHODS

This retrospective longitudinal study of 130 children aged 6 to 18 years between 2000 and 2012 examined 25-OHD levels classed in three vitamin D groups: sufficient (≥30 μg/L), insufficient (20-29 μg/L), and deficient (<20 μg/L). Longitudinal models followed individuals' changing vitamin D groups over time to compare numbers of pulmonary exacerbations (defined by hospitalization), incidence of first P. aeruginosa infection, and % predicted lung function. Cross-sectional comparisons between vitamin D groups were performed at ages 8, 12, and 16 years.

MEASUREMENTS AND MAIN RESULTS

The prevalence of vitamin D deficiency and insufficiency increased slowly through adolescence. The rate of exacerbations for the deficient vitamin D group, aged 15 to 18 years, was 13.1 per 10 patient-years, significantly higher than 4.3 per 10 patient-years for the insufficient and sufficient vitamin D groups (P < 0.05), which were not significantly different There were no differences between vitamin D groups in pulmonary function or incidence of first P. aeruginosa infection, which was about 2 per 10 patient-years.

CONCLUSIONS

Higher 25-OHD levels in children with CF were associated with lower rates of pulmonary exacerbations and, in adolescents, higher FEV1.

Diagnosis and treatment of endocrine comorbidities in patients with cystic fibrosis

PURPOSE OF REVIEW

The aim of this review is to provide an update on various relevant endocrine aspects of care in adolescents and adults with cystic fibrosis.

RECENT FINDINGS

As life expectancy in cystic fibrosis has continuously improved, endocrine complications have become more apparent. The common endocrine complications include cystic fibrosis related diabetes, cystic fibrosis related bone disease, vitamin D deficiency and poor growth and pubertal development. Thyroid and adrenal disorders have also been reported, although the prevalence appears to be less common.

SUMMARY

Endocrine diseases are an increasingly recognized complication that has a significant impact on the overall health of individuals with cystic fibrosis. This review summarizes the updated screening and management of endocrine diseases in the cystic fibrosis population.

The effect of a single, large bolus of vitamin D in healthy adults over the winter and following year: a randomized, double-blind, placebo-controlled trial

BACKGROUND/OBJECTIVES

Although single, high doses of vitamin D effectively maintain vitamin D sufficiency in several populations, no studies have evaluated healthy adults over winter, during which vitamin D status declines. This study investigated whether high-dose vitamin D3 given once to healthy adults before winter will (1) prevent the wintertime decline in vitamin D status, (2) promote vitamin D sufficiency 1 year following the dose and (3) prevent the rise of parathyroid hormone (PTH) concentrations.

SUBJECTS/METHODS

In this double-blind, placebo-controlled trial, we assessed plasma 25(OH)D and PTH concentrations at baseline, 5, 90 and 365 days after drug administration in 28 healthy adults. In all, >80% of subjects returned at each time point.

RESULTS

At baseline, the young, healthy participants had a mean plasma 25(OH)D concentration of 17.5±6.1 ng/ml. Only two subjects exhibited plasma 25(OH)D concentrations >30 ng/ml. At 5 days, subjects randomized to vitamin D3 had a higher mean plasma 25(OH)D concentration compared with the placebo group (39.1 vs 19.1 ng/ml, P<0.001). Plasma 25(OH)D concentrations returned to baseline at 90 and 365 days in the vitamin D3 group and remained unchanged in the placebo group. PTH and calcium concentrations were unrelated to changes in 25(OH)D levels and similar between groups over time.

CONCLUSIONS

A dose of 250,000 IU of vitamin D3 given once in November resulted in a robust increase in plasma 25(OH)D after 5 days, but it was unable to sustain this increase after 90 days. A larger or more frequent dosing regimen may be needed for long-term vitamin D sufficiency.

Could T cells be involved in lung deterioration and hyperglycemia in cystic fibrosis?

Cystic fibrosis-related diabetes (CFRD) is the most frequent complication of cystic fibrosis (CF) and associated with increased mortality. Why patients have an accelerated loss of lung function before the diagnosis of CFRD remains poorly understood. We reported that patients with or without CFRD had increased glucose excursions when compared to healthy peers. Studies have demonstrated that patients with CF have increased glucose fluctuations and hyperglycemia and that this may affect the clinical course of CF and lead to lymphocyte dysfunction. T-helper 17 (Th17) lymphocytes produce and secrete the pro-inflammatory cytokine IL-17. The Th17 pathway is involved in CF lung inflammation, β-cell destruction in type 1 diabetes (T1D) and Th17 cells of patients with type 2 diabetes have increased production of IL-17 when compared to healthy peers. Also, regulatory T-cells (Tregs) have been shown to be dysfunctional and produce IL-17 in T1D. Furthermore, vitamin D can affect inflammation in CF, diabetes and the differentiation of lymphocytes. In this review, we discuss the potential roles of hyperglycemia on Th17 cells, Tregs and IL-17 as a potential cause for accelerated lung function decline before CFRD and how this could be modulated by vitamin D or by directly intervening in the IL-17A pathway.

Prevalence of low bone mineral density in adolescents and adults with cystic fibrosis

OBJECTIVE

The aim of this cross-sectional study was to evaluate the prevalence of low bone mass density in cystic fibrosis patients as well as to evaluate the factors associated with bone mass in such patients.

METHODS

Bone mass density was measured by dual-photon X-ray absorptiometry of lumbar spine (L1-L4), in patients ≤19 years old, or lumbar spine and femur (total and neck) in patients ≥20 years old. Evaluations of nutritional status, biochemical parameters, and lung function were performed. Medication data were obtained from medical records.

RESULTS

Fifty-eight patients were included in the study (25 males/ 33 females), mean age 23.9 years (16-53 years). The prevalence of bone mass below the expected range for age at any site was 20.7%. None of the subjects had history of fracture. Lumbar spine Z-score in cystic fibrosis patients correlated positively with body mass index (r= 0.3, p=0.001), and forced expiratory volume in the first second (% predicted) (r=0.415, p=0.022). Mean lumbar spine Z-score was higher in women (p=0.001), in patients with no pancreatic insufficiency (p=0.032), and in patients with no hospitalization in the last 3 months (p=0.02). After multivariate analysis, body mass index (p= 0.001) and sex (p=0.001) were independently associated with Z-score in lumbar spine.

CONCLUSION

Low bone mass is a frequent problem in patients with CF, being independently associated with body mass index, and male sex.

Vitamin D as an anti-microbial and anti-inflammatory therapy for Cystic Fibrosis

Cystic fibrosis (CF) is characterized by chronic infection and inflammation in the airways that lead to progressive lung damage and early death. Current anti-inflammatory therapies are limited by extensive adverse effects or insufficient efficacy. There is a large body of studies indicating beneficial anti-microbial and anti-inflammatory properties of vitamin D. Since most patients with CF present with vitamin D deficiency, and serum vitamin D levels demonstrate a positive correlation with lung function and negative correlation with airway inflammation and infection, correcting vitamin D deficiency may be an attractive therapeutic strategy in CF. The function of vitamin D is intricately tied to its metabolism, which may be impaired at multiple steps in patients with CF, with a potential to limit the efficacy of vitamin D supplementation. It is likely that the aforementioned beneficial properties of vitamin D require supplementation with doses of vitamin D markedly higher than those recommended to maintain proper bone function. This review will illustrate the potential for supplementation with vitamin D or its metabolites to modulate inflammation and improve defence against chronic infection in CF lung, as well as appropriate vitamin D supplementation strategies for improving lung function in CF.