Vitamin D deficiency as a risk factor for cystic fibrosis-related diabetes in the Scandinavian Cystic Fibrosis Nutritional Study

Importance of Vitamin D Status and Nerve Conduction in Pediatric Cystic Fibrosis Patients

Cystic fibrosis is one of the most common inherited diseases. It presents with recurrent respiratory infections, pancreatic insufficiency, and growth retardation. Neurological involvement becomes more common as life expectancy increases. Chronic hypoxia, impaired glucose intolerance, autoimmune mechanisms, vasculitis changes, and micronutrient deficiencies seem to cause neuropathy in cystic fibrosis. This study was aimed to investigate peripheral neuropathy in pediatric cystic fibrosis patients. Twenty-one cystic fibrosis patients and 19 healthy control subjects between the ages of 7 and 17 years were included. Their nerve conduction study results and laboratory investigations were analyzed. Participants were classified into four groups; 1. Cystic fibrosis with vitamin D deficiency, 2. Cystic fibrosis with normal vitamin D levels, 3. Healthy subjects with vitamin D deficiency, 4. Healthy subjects with normal vitamin D levels. We found statistically significantly lower sensory median nerve sensorial nerve action potential, sensorial sural nerve conduction velocity, and motor peroneal nerve compound motor action potential in cystic fibrosis patients with vitamin D deficiency than in other cases. We also found that the main difference between cystic fibrosis and control groups was especially in patients with low vitamin D levels. Nerve damage starts at an early age, especially in cystic fibrosis patients especially those with vitamin D deficiency. Electrophysiological evaluation to assess neuropathy is important even in asymptomatic patients. Prevention of hypovitaminosis D is important to prevent neuropathy in cystic fibrosis patients.

Development and Evaluation of a Pharmacist-Driven Vitamin D Protocol for a Cystic Fibrosis Clinic

OBJECTIVE

Vitamin D deficiency is commonly found in patients with cystic fibrosis (CF) and can have a negative effect on patients who are not at target goal according to Cystic Fibrosis Foundation's Vitamin D Deficiency Clinical Care Guidelines. The objective of this study is to determine the effectiveness of a pharmacist-driven vitamin D protocol (PDVDP) in improving, achieving, and maintaining 25-hydroxyvitamin D levels of patients in a pediatric CF clinic.

METHODS

A retrospective chart review was conducted for pediatric patients with CF from August 2018 to March 2020 to determine the percent of patients with improvement in 25-hydroxyvitamin D levels to target goal (≥ 30 ng/mL). Patients' 25-hydroxyvitamin D levels at 6, 12, and 18 months after automatic enrollment into the PDVDP were compared to determine if improvement occurred, and to calculate relative percent increase of 25-hydroxyvitamin D levels for these patients.

RESULTS

The mean 25-hydroxyvitamin D levels of the patients at baseline before the protocol and 6, 12, and 18 months after enrollment in the protocol were 23.2, 33.3, 32.7, and 34.6 ng/mL, respectively. These results demonstrate mean 25-hydroxyvitamin D levels at all follow-up time points were significantly greater than baseline (p < 0.001). At 6 months, 50% (n = 20) of pediatric patients reached the target 25-hydroxyvitamin D levels.

CONCLUSIONS

The PDVDP was effective in increasing the number of patients able to reach target 25-hydroxyvitamin D levels. Our PDVDP process may also be used at other CF clinics to improve vitamin D outcomes collaboratively with the interprofessional CF team.

A Clinician’s guide to vitamin D supplementation for patients with cystic fibrosis

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Vitamin D deficiency is multifactorial in the cystic fibrosis population.

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Vitamin D deficiency can adversely affect multiple organ systems in the cystic fibrosis population.

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In the cystic fibrosis population in the United States, we aim to treat to serum 25-hydroxyvitamin D levels over 30 ng/ml.

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Cholecalciferol is used in preference to ergocalciferol.

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Daily or once weekly dosing regimens are chosen according to patient preference and compliance.

Vitamin D deficiency is common in the general population, and even more so in patients with cystic fibrosis. Deficiency is exacerbated in cystic fibrosis patients because of a myriad of causes including malabsorption, decreased fat mass, reduced 25-hydroxylation of vitamin D, reduced exposure to sunlight, decreased vitamin D binding protein, and exposure to drugs that increase catabolism. In turn, vitamin D deficiency can contribute to poor bone health. Additionally, it may contribute to pulmonary decline in the form of worsening pulmonary function, increased colonization with pathogens, and increased pulmonary exacerbation. Because vitamin D deficiency is correlated with negative clinical effects in multiple organ systems of patients with cystic fibrosis, it is important to screen for and treat deficiency in these patients. The Cystic Fibrosis Foundation has issued guidelines for the treatment of vitamin D deficiency, targeting serum levels of 25-hydroxyvitamin D of at least 30 ng/ml. The guidelines offer age-specific escalating dose regimens depending on serum vitamin D levels, with monitoring at 12- week intervals after changing therapy. They address the literature on alternative vitamin D sources, such as UV lamps, ideal formulations (cholecalciferol in preference to ergocalciferol), and optimal vehicles of administration. Despite these detailed recommendations, most centers are still unable to achieve in-target serum vitamin D levels for many of their patients. Future research examining ideal treatment regimens to achieve serum targets and maximize clinical effects are needed. Moreover, it is unknown whether vitamin D sufficiency will be easier to achieve on new triple therapy cystic fibrosis drug combinations, and how these drugs will contribute to vitamin D-related clinical outcomes.

Vitamin D Status and Risk of Cystic Fibrosis-Related Diabetes: A Retrospective Single Center Cohort Study

Objective: Cystic fibrosis-related diabetes (CFRD) affects up to half of the people with cystic fibrosis (CF) by adulthood. CFRD is primarily caused by pancreatic dysfunction that leads to insufficient insulin release and/or insulin resistance. Exocrine pancreatic insufficiency in people with CF is associated with fat-soluble vitamin malabsorption, including vitamins A, D, E, and K. This study examined the relationship between vitamin D status, assessed by serum 25-hydroxyvitamin D (25(OH)D), and the development of CF-related diabetes (CFRD) in adults with CF. Methods: This was a retrospective cohort study of adults seen at a single CF center. The data were extracted from the electronic medical records and the Emory Clinical Data Warehouse, a data repository of health information from patients seen at Emory Healthcare. We collected age, race, the first recorded serum 25-hydroxyvitamin D (25(OH)D) concentration, body mass index (BMI), and onset of diabetes diagnosis. Log-rank (Mantel–Cox) tests were used to compare the relative risk of CFRD onset in the subjects with stratified vitamin D status and weight status. A sub-group analysis using chi-square tests assessed the independence between vitamin D deficiency and CFRD risk factors, including gender and CF mutation types (homozygous or heterozygous for F508del, or others). Unpaired t-tests were also used to compare the BMI values and serum 25(OH)D between the CF adults based on the CFRD development. Results: This study included 253 subjects with a mean age of 27.1 years (±9.0), a mean follow-up time period of 1917.1 (±1394.5) days, and a mean serum 25(OH)D concentration of 31.8 ng/mL (±14.0). The majority (52.6%) of the subjects developed CFRD during the study period. Vitamin D deficiency (defined as 25(OH)D < 20 ng/mL) was present in 25.3% of the subjects. Close to two thirds (64.1%) of the subjects with vitamin D deficiency developed CFRD during the study. Vitamin D deficiency increased the risk of developing CFRD (chi-square, p = 0.03) during the course of the study. The time to the onset of CFRD stratified by vitamin D status was also significant (25(OH)D < 20 ng/mL vs. 25(OH)D ≥ 20 ng/mL) (95% CI: 1.2, 2.7, p < 0.0078). Conclusion: Our findings support the hypothesis that adults with CF and vitamin D deficiency are at a higher risk of developing CFRD and are at risk for earlier CFRD onset. The maintenance of a serum 25(OH)D concentration above 20 ng/mL may decrease the risk of progression to CFRD.

Challenges with optimizing nutrition in cystic fibrosis

Introduction. Optimizing nutrition remains the cornerstone of therapy for patients with cystic fibrosis (CF) since it is associated with better pulmonary function and survival. However, a significant proportion of patients still fail to achieve normal growth and nutritional status. Areas covered. This review describes the current challenges in providing effective nutritional therapy in CF with a focus on the current issues related to energy imbalance, dietary composition, adherence to nutritional recommendations, pancreatic enzyme replacement therapy, and the effects of modulators of the CF transmembrane conductance regulator. Expert opinion. CF is a multisystemic disease that requires a personalized nutritional approach with accurate evaluation of energy balance. There is an urgent need for evidence-based recommendations on the dietary composition, in consideration of the increasing prevalence of overweight, diabetes and the potential effects of fatty acids on inflammation and immune response. More research into new pancreatic enzyme formulations is also required.

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.

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.

Comparing the harmful effects of nontuberculous mycobacteria and Gram negative bacteria on lung function in patients with cystic fibrosis

Background

To better understand the relative effects of infection with nontuberculous mycobacteria and Gram negative bacteria on lung function decline in cystic fibrosis, we assessed the impact of each infection in a Danish setting.

Methods

Longitudinal registry study of 432 patients with cystic fibrosis contributing 53,771 lung function measures between 1974 and 2014. We used a mixed effects model with longitudinally structured correlation, while adjusting for clinically important covariates.

Results

Infections with a significant impact on rate of decline in %FEV1 were Mycobacterium abscessus complex with − 2.22% points per year (95% CI − 3.21 to − 1.23), Burkholderia cepacia complex − 1.95% (95% CI − 2.51 to − 1.39), Achromobacterxylosoxidans − 1.55% (95% CI − 2.21 to − 0.90), and Pseudomonas aeruginosa − 0.95% (95% CI − 1.24 to − 0.66). Clearing M. abscessus complex was associated with a change to a slower decline, similar in magnitude to the pre-infection slope.

Conclusions

In a national population we have demonstrated the impact on lung function of each chronic CF pathogen. M. abscessus complex was associated with the worst impact on lung function. Eradication of M. abscessus complex may significantly improve lung function.

Dietary intake and nutritional status of micronutrients in adults with cystic fibrosis in relation to current recommendations

An increased prevalence of cystic fibrosis (CF) related complications such as impaired bone health and diabetes has accompanied increased survival of patients with CF. This review was conducted to determine the extent to which adults with CF are meeting current nutrition recommendations for micronutrients in association with CF-related complications management. Although dietary intake and nutritional status in CF has improved significantly in recent decades, micronutrient status seems to have diverged. While vitamin A and E intakes appear adequate, frequent vitamin D and K deficiency/insufficiency and compromised bone health in CF, occurs despite supplementation. Although deficiency of water-soluble vitamins and minerals is uncommon, ongoing surveillance will enhance overall health outcomes, particularly in cases of CF-related liver disease and deteriorated lung function and bone health. Salt and fluid status in CF may also need attention due to diminished thirst sensation and voluntary rehydration. Further investigation in micronutrient status optimisation in CF will inform the development of more effective and targeted nutrition therapies to enable integration of more refined recommendations for micronutrient intakes in CF based on individual needs and disease progression.

Management of endocrine disease: Cystic fibrosis-related diabetes: novel pathogenic insights opening new therapeutic avenues

Cystic fibrosis (CF) is a recessive genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR). CFTR is primarily present in epithelial cells of the airways, intestine and in cells with exocrine and endocrine functions. Mutations in the gene encoding the channel protein complex (CFTR) cause alterations in the ionic composition of secretions from the lung, gastrointestinal tract, liver, and also the pancreas. CF-related diabetes (CFRD), the most common complication of CF, has a major detrimental impact on pulmonary function, nutrition and survival. Glucose derangements in CF seem to start from early infancy and, even when the pathophysiology is multifactorial, insulin insufficiency is clearly a major component. Consistently, recent evidence has confirmed that CFTR is an important regulator of insulin secretion by islet β-cells. In addition, several other mechanisms were also recognized from cellular and animals models also contributing to either β-cell mass reduction or β-cell malfunction. Understanding such mechanisms is crucial for the development of the so-called 'transformational' therapies in CF, including the preservation of insulin secretion. Innovative therapeutic approaches aim to modify specific CFTR mutant proteins or positively modulate their function. CFTR modulators have recently shown in vitro capacity to enhance insulin secretion and thereby potential clinical utility in CFDR, including synergistic effects between corrector and potentiator drugs. The introduction of incretins and the optimization of exocrine pancreatic replacement complete the number of therapeutic options of CFRD besides early diagnosis and implementation of insulin therapy. This review focuses on the recently identified pathogenic mechanisms leading to CFRD relevant for the development of novel pharmacological avenues in CFRD therapy.

Epidemiology of nontuberculous mycobacteria among patients with cystic fibrosis in Scandinavia

Background

Nontuberculous mycobacteria (NTM) are an emerging threat to cystic fibrosis (CF) patients but their epidemiology is not well described.

Methods

In this retrospective observational study we identified all Scandinavian CF patients with a positive NTM culture from airway secretions from 2000 to the end of 2012 and used national CF databases to describe microbiological and clinical characteristics.

Results

During the 13-year period 157 (11%) CF patients were culture positive for NTM at least once. Mycobacterium abscessus complex (MABSC) (45%) and Mycobacterium avium complex (MAC) (32%) were the predominant species with geographical differences in distribution. Younger patients were more prone to MABSC (p < 0.01). Despite treatment, less than one-third of MABSC patients with repeated positive cultures cleared their infection and a quarter had a lung transplant or died.

Conclusion

NTM are significant CF pathogens and are becoming more prevalent in Scandinavia. MABSC and MAC appear to target distinct patient groups. Having multiple positive cultures despite treatment conveys a poor outcome.

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.