Bone mass density and associated factors in cystic fibrosis patients of young age

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.

Evaluation of bone metabolism in children with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) bone disease (CFBD) has attracted considerable recent interest from researchers, although several aspects of CFBD pathophysiology remain poorly understood. The objective of this research was to investigate CFBD in children with CF and its relation to clinical and bone metabolism markers.

METHODS

In a prospective observational study of 68 patients with CF and 63 healthy controls, we studied bone turnover biomarkers and bone mineral density (BMD). The biomarkers included osteocalcin, total-alkaline phosphatase, bone-alkaline phosphatase, N-terminal propeptide of type-1-procollagen, osteoprotegerin (OPG), interleukine-6, tumor necrosis factor alpha (TNF-α), type-1-collagen cross-linked C-telopeptide (CTX), parathormone (PTH), 25-vitamin D, 1,25-vitamin D, calcium and phosphorus. BMD was examined in lumbar spine, comparing two healthy Spanish populations. Two regression analyses were applied to any significant associations to evaluate predictors of BMD and of CF, expressed as odds ratios (OR) with 95% confidence intervals.

RESULTS

After adjusting for age, sex, and height Z-score, gains in BMD LS in children and adolescents (6-16 years) with CF were not less than in healthy reference population. Patients with CF showed significant associations with different bone turnover biomarkers. Age, gender, body mass index, PTH, CTX and OPG were significant predictors of BMD (R² = 0.866, p < 0,001). Moreover, we found that PTH (OR = 1.070; 95% CI 1.019-1.123), and TNFα (OR = 2.173; 95% CI 1.514-3.118) were significantly linked to CF, and calcium (OR = 0.115; 95% CI 0.025-0.524), 1,25-vitamin D (OR = 0.979; 95% CI 0.962 0.996) and OPG (OR = 0.189; 95% CI 0.073-0.489) were significant reduced.

CONCLUSION

A normal bone mineral density along with altered remodeling was found in CF patients with a normal nutritional status and without acute lung disease.

Screening for the Most Common Mutations of CFTR Gene among Egyptian Children with Difficult-to-Treat Asthma

Cystic fibrosis (CF) is panethnic autosomal recessive disease that affects the exocrine glands of pancreas, lungs, and intestine. It is often misdiagnosed in developing countries as difficult-to-treat asthma. We enrolled 150 Egyptian families with one or more probands who were complaining of difficult-to-treat asthma, and 112 cases were studied extensively through history taking including pedigree construction and clinical examination. In addition, spirometry and computed tomography of the chest were done in selected cases. All cases were subjected to quantitative sweat chloride test and molecular screening for the three most common mutations of cystic fibrosis transconductance regulator ( CFTR ) gene ( ΔF508 , G542X , W1282X ) using amplification refractory mutation system (ARMS) technique. Probands of difficult-to-treat asthma comprised 66 males and 46 females; their age range was 1 to 14 years. Sixty-one probands (54.5%) were carriers of one or more of the studied mutations (36 cases and 25 carriers). Six carriers of single mutations had mild respiratory symptoms and negative sweat test. The most common allele was ΔF508 , 60 alleles in 56 individuals (4 were homozygous ΔF508 / ΔF508 ) followed by W1282X in 25 individuals and G542X in 12 individuals. Allele W1282X had an increased risk of recurrent chest infection and bronchiectasis. Moreover, cases with two mutations had more severe symptoms compared with those with a single mutation. CFTR mutations and CF-related syndromes are not rare as thought in Egypt, especially among the high-risk difficult-to-treat asthma. The readily available ARMS technique is recommended for ΔF508 and/or W1282X screening on priority basis among these children.

Vitamin K and cystic fibrosis: A gordian knot that deserves our attention

Cystic fibrosis (CF) is an inherited genetic disorder with multiorgan involvement. Gastrointestinal tract dysfunction leads to fat and fat-soluble vitamins (A,D,E,K) malabsorption and deficiency of these vitamins. Subclinical vitamin K (VK) deficiency seems to be a common problem in CF patients. However, despite the rest of fat-soluble vitamins being routinely supplemented, this is not a universal clinical practice for VK. Inefficient levels of VK may have significant effects on blood coagulation and bone formation. There are also some data indicating that VK may play a key role on regulation of inflammation. Supplementing CF patients with VK seems rational, but the appropriate dosing regimens are still a matter of debate. This review will try to delineate the problem and communicate the latest opinions on this controversial issue.

Peripheral quantitative computed tomography detects differences at the radius in prepubertal children with cystic fibrosis compared to healthy controls

Introduction

In 2015, 11.9% of people with cystic fibrosis (CF) in the United States had osteopenia, 5.1% osteoporosis, and 0.3% experienced a fracture. Screening for CF-related bone disease starts in childhood, and dual energy x-ray absorptiometry (DXA) is the recommended method. It is unknown whether peripheral quantitative computed tomography (pQCT) can detect deficits earlier than DXA. This study compared pQCT and DXA scans in a group of pre-pubertal children with CF and healthy controls.

Methods

This was a cross-sectional study of children at Tanner stage 1. A pQCT scan of the radius at proximal and distal sites was performed plus a total body DXA scan. Serum C-reactive protein, interleukin-6 and tumor necrosis factor-alpha were also measured.

Results

A total of 34 subjects completed the study; 14 with CF and 20 controls. At the distal radius, pQCT showed a lower total bone mineral density (BMD) Z-score for the CF group (P = 0.01 and P = 0.03 for 2 different reference databases) compared to controls. At the proximal site, the polar strength-strain index was lower in the CF group (P = 0.017). Finally, the total body BMD Z-score by DXA was lower in the CF group, although it did not meet the definition of reduced bone density (P = 0.004). Biomarkers of inflammation were not different.

Conclusions

In this group of pre-pubertal children with CF, measures of bone strength and density by both pQCT and DXA were reduced compared to healthy controls.

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.

Evaluation of factors related to bone disease in Polish children and adolescents with cystic fibrosis

PURPOSE

The aim of the study was to evaluate factors related to bone formation and resorption in Polish children and adolescents with cystic fibrosis and to examine the effect of nutritional status, biochemical parameters and clinical status on bone mineral density.

MATERIALS AND METHODS

The study group consisted of 100 children and adolescents with cystic fibrosis with a mean age 13.4 years old. Anthropometric measurements, included body height, body mass and body mass index (BMI); bone mineral densitometry and biochemical testing were performed. Bone mineral density was measured using a dual-energy X-ray absorption densitometer. Biochemical tests included serum calcium, phosphorus, parathyroid hormone and vitamin D concentrations, as well as 24-h urine calcium and phosphorus excretion. Pulmonary function was evaluated using FEV1%, and clinical status was estimated using the Shwachman-Kulczycki score.

RESULTS

Standardized body height, body mass and BMI were significantly lower than in the reference population. Mean serum vitamin D concentration was decreased. Pulmonary disease was generally mild, with a mean FEV1% of 81%. Multivariate linear regression revealed that the only factors that had a significant effect on bone marrow density were BMI and FEV1%. There were no significant correlations between bone mineral density and the results of any of the biochemical tests performed.

CONCLUSIONS

Nutritional status and bone mineral density were significantly decreased in children and adolescents with cystic fibrosis. In spite of abnormalities in biochemical testing, the factors that were found to have the strongest effect on bone mineral density were standardized BMI and clinical status.

Bone Mineral Density in Cystic Fibrosis Patients with the CFTR I1234V Mutation in a Large Kindred Family Is Associated with Pancreatic Sufficiency

Objectives. To study bone mineral density (BMD) in cystic fibrosis (CF) children and adults with the CFTR I1234V mutation associated with pancreatic sufficiency. Methods. Lumbar spine, total hip, and whole-body mineral density were measured by dual-energy radiographic absorptiometry (DEXA) scan. Z score was used for those less than 21 years and T score was used for those 21 years or older. Results. Twenty-one CF patients were younger than 21 years and 5 CF patients were 21 years or older. Mean age was 17.29 ± 4.95 years, ranging from 10 to 33 years. The mean BMD Z scores for patients younger than 21 years were −0.69 ± 0.96 (lumbar spine = L1–L4), −0.48 ± 0.92 (total hip), and −0.38 ± 0.86 (total body). The mean T scores for patients 21 years or older were 0.14 ± 0.7 (L1–L4), 0.38 ± 1 (total hip), and 0.52 ± 1.03 (total body). BMD reduction less than −1 was found in 7 (26.9%) CF patients. Vitamin D deficiency in 20 CF patients (76.9%) tended to be lower in CF patients with low BMD. BMD was significantly correlated with FEV1; however, no significant association was observed with P. aeruginosa colonization. Conclusion. BMD reduction does occur in patients with mild CFTR mutation associated with pancreatic sufficiency.

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.

Bone health in children and adolescents with chronic diseases that may affect the skeleton: the 2013 ISCD Pediatric Official Positions

The aim of this Task Force was to review the use of dual-energy X-ray absorptiometry (DXA) in children and adolescents with underlying chronic diseases that pose risk factors for compromised bone health, such as inflammation, glucocorticoid therapy, or decreased mobility. The Task Force systematically analyzed more than 270 studies, with an emphasis on those published in the interval since the original 2007 Position Statements. Important developments over this period included prospective cohort studies demonstrating that DXA measures of areal bone mineral density (aBMD) predicted incident fractures and the development of robust reference data and strategies to adjust for bone size in children with growth impairment. In this report, we summarize the current literature on the relationship between DXA-based aBMD and both fracture (vertebral and non-vertebral) outcomes and non-fracture risk factors (e.g., disease characteristics, ambulatory status, and glucocorticoid exposure) in children with chronic illnesses. Most publications described the aBMD profile of children with underlying diseases, as well as the cross-sectional or longitudinal relationship between aBMD and clinically relevant non-fracture outcomes. Studies that addressed the relationship between aBMD and prevalent or incident fractures in children with chronic illnesses are now emerging. In view of these updated data, this report provides guidelines for the use of DXA-based aBMD in this setting. The initial recommendation that DXA is part of a comprehensive skeletal healthy assessment in patients with increased risk of fracture is unchanged. Although the prior guidelines recommended DXA assessment in children with chronic diseases at the time of clinical presentation with ongoing monitoring, this revised Position Statement focuses on the performance of DXA when the patient may benefit from interventions to decrease their elevated risk of a clinically significant fracture and when the DXA results will influence that management.

Vitamin D: effects on childhood health and disease

Vitamin D is a key nutrient for both healthy children and those with chronic illnesses. Understanding its roles in health and disease has become one of the most important issues in the nutritional management of children. Formal guidelines related to nutrient requirements for vitamin D in healthy children, recommending dietary intakes of 400 IU per day for infants and 600 IU per day for children over 1 year of age, were released by the Institute of Medicine in November 2010. However, application of these guidelines to children with acute and chronic illnesses is less clear. In this Review, we consider major illness categories and specific examples of conditions in children that might be affected by vitamin D. This information can be used in developing both model systems of investigation and clinical trials of vitamin D in children with acute and chronic illnesses.

Bone mineral density, pulmonary function, chronological age, and age at diagnosis in children and adolescents with cystic fibrosis

OBJECTIVE

To assess bone mineral density in patients with cystic fibrosis (CF), and to correlate it with possible intervening variables.

METHODS

Children and adolescents diagnosed with CF, aged 6 to 18 years, followed at the outpatient clinic were included in the study. First, demographic data were collected and, subsequently, patients underwent a spirometric test. All patients answered the Cystic Fibrosis Quality of Life Questionnaire (CFQ) and underwent the six-minute walk test (6MWT) and bone densitometry (DXA).

RESULTS

A total of 25 CF patients were included, of which 56% were males. The mean age was 12.3±3.4 years; mean height was 149.2±14.4 cm; and mean weight was 44.4±13.9 kg. Most results on pulmonary function and bone mineral density (BMD) were within normal limits. The mean forced expiratory volume in one second (FEV) was 92.5±23.6 (% of predicted), mean forced vital capacity (FVC) was 104.4±21.3 (% of predicted), and1 mean BMD z-score was 0.1±1.0. BMD was moderately correlated with FEV (r = 0.43, p = 0.03) and FVC (r = 0.57, p = 0.003). Regarding chronological age and age at diagnosis, a moderate and inverse correlation was also found (r = -0.55, p = 0.004; r = -0.57, p = 0.003, respectively). However, no significant correlations were found with the data from CFQ, 6MWT, and body mass index.

CONCLUSION

Most patients had BMD within normal limits and presented a positive correlation with pulmonary function, as well as a negative correlation with chronological age and age at diagnosis.

The impact of dysglycaemia on bone mineral accrual in young people with cystic fibrosis

OBJECTIVE

The effect of dysglycaemia on bone mineral density (BMD) has not been studied in young people with CF. We examined factors associated with BMD in a tertiary paediatric CF clinic.

DESIGN

Retrospective, clinic-based study at The Children's Hospital at Westmead, Sydney.

PATIENTS

Young people with CF aged ≤ 18 years.

MEASUREMENTS

Bone mineral density was measured by dual-energy X-ray absorptiometry; main outcome measures were total body (TB), lumbar spine (LS) and femoral neck (FN) BMD and bone mineral content (BMC), and LS volumetric BMD (vBMD), reported as z scores for height. Dysglycaemia, based on oral glucose tolerance test, was defined as CF-related diabetes (CFRD) or impaired glucose tolerance (IGT).

RESULTS

Overall, 14 of 81 (17%) had CFRD, 6 (7%) IGT and 61 (76%) normal glucose tolerance (NGT). Mean age was 14.9 ± 2.4 years and mean height z score -0.68 ± 1.39. Osteopenic (z score ≤-2) TB, LS or FN BMD was present in 30 of 81 (37%), BMC in 42 (52%) and vBMD in 10 (5%). Across the three groups, there were differences in LS vBMD (CFRD, -0.67 ± 0.76; IGT, -0.52 ± 0.76; NGT, -0.05 ± 1.39; P = 0.04), LS BMD (P < 0.01), LS BMC (P = 0.01) and TB BMD (P = 0.01). In multivariate linear regression, LS BMC was associated with dysglycaemia (β = 0.56; 95% CI, 0.00-1.13; P = 0.05) and approached significance for FEV(1) (β = 0.01; 95% CI, 0.00-0.02; P = 0.06).

CONCLUSIONS

Dysglycaemia is associated with reduced bone mass accrual in youth with CF, in addition to recognized factors such as abnormal lung function, poor nutritional status and disease severity. Bone health assessment is essential in youth with CF.

Prevalence of bone loss in a population with cystic fibrosis

The adverse effect of an increased life expectancy for people with cystic fibrosis (CF) is the increased risk of complications, such as CF-related low bone mineral density (BMD). Diagnosis of CF-related low BMD is confirmed by a dual-energy X-ray absorptiometry (DXA) scan. This study reports the results of an audit of DXA scans in 108 adults with CF in our clinic. The most common risk factors for bone loss were vitamin D deficiency (89%), CF-related diabetes (53%), low body mass index (39%) and post-lung transplant (25%); half of those with bone loss were genotype homozygous DF508. Overall fracture incidence was 5.5%; low BMD was not associated with high fracture rates. Thus BMD may not be a good predictor of fracture risk. Treatment includes bisphosphonates, which are difficult to take and have uncertain long-term effects. It is unknown whether bisphosphonate therapy is justified in this already overburdened group.

Bone and body composition analyzed by Dual-energy X-ray Absorptiometry (DXA) in clinical and nutritional evaluation of young patients with Cystic Fibrosis: a cross-sectional study

Background

the improved general therapy has led to reduced morbidity and mortality from Cystic Fibrosis (CF), and bone status may have a potentially greater clinical impact.

We investigated the correlation between the severity of the clinical condition, bone status and body composition parameters, in a group of children and young adults with CF.

Methods

we measured lumbar spine bone density and total body composition by dual energy x-ray absorptiometry (DXA) in 82 consecutive CF patients (42 males; median age: 13 years - range: 5-30). Eighty-two healthy subjects, matched for age, gender, height and pubertal stage were recruited as a control group.

Results

37 patients (45.1%) had a normal bone mineral density (BMD). A BMD reduction were observed in 45 (54.8%) patients. Lumbar spine Z score was positively related to Body Mass Index (BMI) and a higher Shwachman-Kulczycki score, and negatively related to Crispin-Norman score. A positive and significant correlation was also observed between lumbar spine Z score and total body composition.

Conclusion

a significant BMD reduction can be present early in CF children and adolescents. A careful follow up of bone status is required starting in childhood.

Symposium 6: Young people, artificial nutrition and transitional care The nutritional challenges of the young adult with cystic fibrosis: transition

Cystic fibrosis (CF) is a complex multisystem disorder affecting mainly the gastrointestinal tract and respiratory system. Intestinal malabsorption occurs in approximately 90% of patients. In the past, malnutrition was an inevitable consequence of disease progression, leading to poor growth, impaired respiratory muscle function, decreased exercise tolerance and immunological impairment. A positive association between body weight and height and survival has been widely reported. The energy requirements of patients with CF vary widely and generally increase with age and disease severity. For many young adults requirements will be 120–150% of the age-related estimated average requirement. To meet these energy needs patients are encouraged to eat a high-fat high-energy diet with appropriate pancreatic enzyme supplements. Many patients are unable to achieve an adequate intake as a result of a variety of factors including chronic poor appetite, infection-related anorexia, gastro-oesophageal reflux and abdominal pain. Oral energy supplements and enteral tube feeding are widely used. Nutritional support has been shown to improve nutritional status and stabilise or slow the rate of decline in lung function. With such emphasis on nutritional intake and nutritional status throughout life, poor adherence to therapies and issues relating to body image are emerging. The median survival of patients with CF is increasing. CF is now considered a life-limiting disease of adulthood rather than a terminal childhood illness. With increased longevity new challenges are emerging that include the transition of young adults with CF to adult services, CF-related diabetes, disordered eating, osteoporosis, liver disease and transplantation.