Hidden Depletion of Fat-Free Mass and Bone Mineral Density in Adults With Cystic Fibrosis

Implementation and outcomes of a quality improvement project to systematically assess the gross motor skills in school-aged children with cystic fibrosis

INTRODUCTION

Limited data exist on the gross motor abilities of children with cystic fibrosis (CF). The objective of this research project was to implement a systematic gross motor assessment in children with CF ages 4-12 years. Secondarily, we aimed to assess demographic characteristics associated with gross motor delays.

METHODS

Physical therapists aimed to evaluate at least 50% of eligible children (4-12 years) at our CF Center over 1 year using the Bruininks-Oseretsky Test of motor Proficiency, second edition (BOT-2). Delays are defined by scores less than 18th percentile. Demographic and clinical data included body mass index, hospitalizations, genotype, and comorbidities. Basic descriptive statistics summarized patient information. Parametric and nonparametric methods compared groups of interest. Linear regression assessed associations between BOT-2 measures and clinical characteristics.

RESULTS

The BOT-2 evaluation was successfully implemented with 69% of eligible patients being evaluated. Forty-five (62.5%) scored below average. Impaired strength (22.2%) was most common, followed by impaired balance (16.7%), running speed and agility (15.3%), and bilateral coordination (8.3%). 15.5% scored below average on their total motor composite score (TMC). Increased age, comorbidities and hospitalizations were associated with a lower TMC.

CONCLUSIONS

The BOT-2 was successfully implemented as part of routine CF care to screen for gross motor delays in children. Results suggest that a high percentage of children with CF, especially older children with comorbid conditions or a history of hospitalization, have impaired gross motor function. These findings support the need for routine gross motor evaluations and physical therapy interventions within pediatric CF clinics.

Effects of a remotely supervised resistance training program on muscle strength and body composition in adults with cystic fibrosis: Randomized controlled trial

INTRODUCTION

Among the limited studies on physical exercise interventions in adults with cystic fibrosis (CF), few have specifically addressed the improvement of peripheral muscle strength and body fat-free mass. The aim of this study was to examine the impacts of a remotely supervised, individualized 8-week resistance training program of moderate to high intensity on strength and body composition in these subjects.

METHODS

This was a randomized controlled trial performed in adults with CF. The exercise group (EX) performed three 1-h resistance training sessions per week over 8 weeks. The control group (CON) followed the physical activity recommendations of their physician. The main outcomes were muscle strength and body composition, with secondary measures including pulmonary function and quality of life. Two-way repeated measures analysis was used.

RESULTS

In 23 participants (age 32.13 ± 7.72 years), the intervention showed a significant beneficial effect on leg press strength, with a large effect size, both in absolute (p = 0.011;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.281) and relative (p = 0.007;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.310) terms. Large intervention effects were observed on total fat mass (p < 0.001;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.415), body adiposity index (p < 0.001;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.436), and fat mass index (p < 0.001;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.445), all showing reduction in the EX group. In addition, significant large size effects were detected on total fat-free mass (p = 0.046;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.177), trunk fat-free mass (p = 0.039;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.188), and fat-free mass index (p = 0.048;η p 2 $$ {\eta}_{\mathrm{p}}^2 $$  = 0.174), all favoring exercise. No significant effects were observed on pulmonary function and quality of life.

CONCLUSIONS

An 8-week remotely supervised resistance training program, with moderate to high intensity, effectively improved lower limb muscle strength and body composition.

Body composition and body mass index measures from 8 to 18 years old in children with cystic fibrosis

BACKGROUND

Historically, body mass index (BMI) >50th percentile has represented optimal nutritional status in children with cystic fibrosis (CF) due to its positive association with lung function. Body composition parameters including fat-free mass index (FFMI) have been suggested as a more physiological nutrition benchmark.

AIMS

(1) describe changes in body composition with age and gender; (2) assess the correlation between measures of nutritional status (FFMI-z, FMI-z, BMI-z) and lung function (forced expiratory volume in one second predicted; FEV1pp).

METHODS

This retrospective, mixed cross-sectional and serial measures study consisted of children with CF (8 to 18 years) attending Sydney Children's Hospital (2007-2020). FFMI and fat mass index (FMI) were taken from biennial dual energy x-ray absorptiometry (DXA) scans. Z-scores were derived using Well's reference population [1]. Repeated measures correlation analyses assessed correlations between FFMI-z, FMI-z, and BMI-z with FEV1pp.

RESULTS

339 DXA reports were analysed from 137 patients. There were slight downwards trends in BMI-z and FMI-z, and an upwards trend in FFMI-z with increasing age and across both genders. Females had higher FMI-z and FFMI-z than males from 12.5 years. There was a weak, positive correlation between FEV1pp and BMI-z (r = 0.14, p = 0.04), and FFMI-z (r = 0.25, p<0.001). FMI-z had no correlation with FEV1pp (r=-0.06, p = 0.41).

CONCLUSION

Deficits in FFMI exist despite increasing trends with age. FFMI-z and BMI-z had a weak, positive correlation with FEV1pp. In contemporary cohorts, nutritional status (reflected by surrogate markers such as FFMI and BMI) may be less influential upon lung function than in previous decades. [1]: Wells, J.C., et al. Body-composition reference data for simple and reference techniques and a 4-component model: a new UK reference child. Am. J. Clin. Nutr.96, 1316-1326 (2012).

High-Fat Diet Related Lung Fibrosis-Epigenetic Regulation Matters

Pulmonary fibrosis (PF) is an interstitial lung disease characterized by the destruction of the pulmonary parenchyma caused by excessive extracellular matrix deposition. Despite the well-known etiological factors such as senescence, aberrant epithelial cell and fibroblast activation, and chronic inflammation, PF has recently been recognized as a metabolic disease and abnormal lipid signature was observed both in serum and bronchoalveolar lavage fluid (BALF) of PF patients and mice PF model. Clinically, observational studies suggest a significant link between high-fat diet (HFD) and PF as manifested by high intake of saturated fatty acids (SFAs) and meat increases the risk of PF and mice lung fibrosis. However, the possible mechanisms between HFD and PF remain unclear. In the current review we emphasize the diversity effects of the epigenetic dysregulation induced by HFD on the fibrotic factors such as epithelial cell injury, abnormal fibroblast activation and chronic inflammation. Finally, we discuss the potential ways for patients to improve their conditions and emphasize the prospect of targeted therapy based on epigenetic regulation for scientific researchers or drug developers.

Physical activity and liver disease affect the fat-free mass in adolescents with cystic fibrosis

Cystic fibrosis (CF) is predominantly a lung disease but is also characterised by impaired skeletal muscularity and a reduction in fat-free mass. We aimed to test the hypothesis that clinical and anthropometric parameters would determine fat-free mass impairment in adolescents with CF. We measured the fat-free mass index (FFMI) using bioelectrical impedance, the lung function using spirometry, the number of shuttles as a measure of exercise tolerance and the reported physical activity in children and young people with CF in a tertiary centre at King's College Hospital, London, UK. CF-related liver disease was diagnosed by abnormal liver enzymes and/or ultrasonography. We studied 28 children and young people (11 male) with a median (interquartile range (IQR)) age of 15 (13-17) years. They had a median (IQR) FFMI of 13.5 (11.6-15.1) kg/m². The FFMI significantly correlated with age (rho = 0.568, p = 0.002), number of shuttles (rho = 0.691, p < 0.001) and reported hours of activity per day (rho = 0.426, p = 0.024). The median (IQR) FFMI was significantly higher in male [15.1 (13.1-18.6) kg/m²] compared to female participants [12.7 (11.6-14.1) kg/m², p = 0.008]. The median (IQR) FFMI was significantly lower in the 10 (36%) participants with liver disease [11.9 (11.5-13.4) kg/m²] compared to the FFMI in the remaining 18 participants without liver disease [14.4 (12.5-15.9) kg/m², p = 0.027].

CONCLUSION

Fat-free mass increases with increasing age and growth in adolescents with CF. Physical activity exerts a beneficial effect on fat-free mass, and CF-related liver disease negatively affects fat-free mass in adolescents with CF.

WHAT IS KNOWN

• Health behaviours in adolescence influence lifelong health in cystic fibrosis (CF). • A normal body mass index in CF might fail to reveal a low fat-free mass (FFM), and quality of life in CF is strongly associated with a reduced FFM.

WHAT IS NEW

• FFM increases with increasing age and growth in adolescents with CF. • Physical activity exerts a beneficial effect, and liver disease negatively affects FFM in adolescents with CF.

Association of Body Mass Index With Clinical Outcomes in Patients With Cystic Fibrosis: A Systematic Review and Meta-analysis

IMPORTANCE

The prevalence of overweight (body mass index [BMI] = 25-29.9 [calculated as weight in kilograms divided by height in meters squared]) and obesity (BMI ≥30) is increasing among patients with cystic fibrosis (CF). However, it is unclear whether there is a benefit associated with increasing weight compared with the reference range (ie, normal) in CF.

OBJECTIVE

To evaluate the association of altered BMI or body composition and clinical outcomes in patients with CF.

DATA SOURCES

For this systematic review and meta-analysis, the literature search was conducted November 2, 2020, of 3 databases: MEDLINE (via PubMed), Embase, and Cochrane Central Register of Controlled Trials.

STUDY SELECTION

Patients older than 2 years diagnosed with CF with altered body composition or BMI were compared with patients having the measured parameters within the reference ranges. Records were selected by title, abstract, and full text; disagreements were resolved by consensus. Cohort studies and conference abstracts were eligible; articles with no original data and case reports were excluded.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data, which were validated by a third author. Studies containing insufficient poolable numerical data were included in the qualitative analysis. A random-effects model was applied in all analyses.

MAIN OUTCOMES AND MEASURES

Pulmonary function, exocrine pancreatic insufficiency (PI), and CF-related diabetes (CFRD) were investigated as primary outcomes. Odds ratios (ORs) or weighted mean differences (WMDs) with 95% CIs were calculated. The hypothesis was formulated before data collection.

RESULTS

Of 10 524 records identified, 61 met the selection criteria and were included in the qualitative analysis. Of these, 17 studies were included in the quantitative synthesis. Altogether, 9114 patients were included in the systematic review and meta-analysis. Overweight (WMD, -8.36%; 95% CI, -12.74% to -3.97%) and obesity (WMD, -12.06%; 95% CI, -23.91% to -0.22%) were associated with higher forced expiratory volume in the first second of expiration compared with normal weight. The odds for CFRD and PI were more likely in patients of normal weight (OR, 1.49; 95% CI, 1.10 to 2.00) than in those who were overweight (OR, 4.40; 95% CI, 3.00 to 6.45). High heterogeneity was shown in the analysis of pulmonary function (I2 = 46.7%-85.9%).

CONCLUSIONS AND RELEVANCE

The findings of this systematic review and meta-analysis suggest that the currently recommended target BMI in patients with CF should be reconsidered. Studies with long-term follow-up are necessary to assess the possible adverse effects of higher BMI or higher fat mass in patients with CF.

Overweight and cystic fibrosis: An unexpected challenge

Achieving a healthy weight balance has been a central focus of care for people who have cystic fibrosis (CF). Over the years, the emphasis has primarily been on promoting weight gain to optimize pulmonary outcomes. With continued improvements in CF care, including highly effective CF modulators available for many people, the CF community is now experiencing a new challenge: addressing the concern that some people are gaining weight excessively. While at this time, we do not know to what extent overweight and obesity will affect health outcomes for people with CF, it is likely that excessive weight gain may have negative health impacts similar to those seen in the general population. In this paper, we review the history of nutritional guidelines for people with CF, as well as more recent trends toward overweight and obesity for some. A multidisciplinary approach is needed to collaboratively start the oftentimes difficult conversation regarding excessive weight gain, and to identify resources to help people achieve and maintain a healthy weight through diet, exercise, and behavioral modification.

The Impact of Highly Effective CFTR Modulators on Growth and Nutrition Status

Patients with cystic fibrosis (CF) are at increased risk of malnutrition and growth failure due to multiple factors as a result of suboptimal or absent function of the CFTR chloride channel protein. Dysfunctional CFTR contributes to increased energy expenditure, exocrine pancreatic insufficiency causing impaired dietary macronutrient digestion and absorption, intestinal dysbiosis, and impaired bile acid homeostasis. Poor nutritional status as a result of these mechanisms is associated with decreased lung function, worse clinical outcomes, and ultimately, increased mortality. Nutritional interventions addressing these mechanisms, such as pancreatic enzyme-replacement therapy and enteral caloric supplementation, have improved nutritional status and, by association, clinical outcomes. In the last decade, the advent of medications targeting defective CFTR proteins has revolutionized the care of patients with CF by reducing the overall impact of CFTR dysfunction. Below, we summarize the effects of highly effective CFTR modulators on nutritional status overall as well as specific factors including bile acid metabolism, pancreatic function, energy expenditure, and intestinal dysbiosis. The future of CF nutrition care will require a paradigm shift away from focusing on methods addressing CFTR dysfunction such as excess calorie provision and toward an individualized, holistic approach in the context of specific mutations and CFTR-directed therapy.

Academy of Nutrition and Dietetics: 2020 Cystic Fibrosis Evidence Analysis Center Evidence-Based Nutrition Practice Guideline

The Academy of Nutrition and Dietetics Evidence Analysis Center conducted a systematic review of the literature to develop an evidence-based practice guideline for primary nutrition issues in cystic fibrosis (CF). This guideline is designed to complement and build upon existing evidence-based CF nutrition guidelines. The objective of this guideline was to provide recommendations for registered dietitian nutritionists in the United States delivering medical nutrition therapy to individuals with CF and their families that fill gaps in current evidence-based guidelines on topics that are crucial in order to improve health and prevent disease progression. This guideline provides 28 nutrition recommendations to guide medical nutrition therapy, including nutrition screening, nutrition assessment, and dietary intake. For topics outside the scope of this guideline, practitioners are referred to external, evidence-based recommendations. The CF landscape is evolving rapidly with breakthroughs in cystic fibrosis transmembrane regulator modulators changing CF at a cellular level. Medical nutrition therapy for individuals with CF from infancy through advanced age requires novel and individualized approaches. The Academy Evidence Analysis Library CF guidelines provide a framework for expanding upon current knowledge to determine effective nutrition strategies for individuals with CF through long and healthy futures.

Limb muscle size and contractile function in adults with cystic fibrosis: A systematic review and meta-analysis

BACKGROUND

There is conflicting evidence regarding the presence of limb muscle impairments in adults with cystic fibrosis (CF), and the factors associated with these muscle impairments. The objectives of this study were to compare limb muscle size and function between adults with CF and healthy controls; and to examine their associations with demographic and clinical variables in adults with CF.

METHODS

The systematic review was performed using PRISMA guidelines. Studies were included if they measured any aspect of limb muscle size or function in adults with CF. Meta-analyses were performed to compare muscle variables between CF and healthy controls; and to examine their associations with demographic and clinical variables.

RESULTS

Twenty-eight studies were included, with 747 adults with CF. The meta-analyses showed that adults with CF have smaller thigh muscles [standardized mean difference (SMD) = 0.57, p<.0011, I²=0%], and lower handgrip strength (SMD = 0.89, p=.0034, I²=74.03%), which was weakly correlated with forced expiratory volume in one second (FEV₁) (r=0.24, p=.035, I²=0%) and lower in females with CF (SMD = 2.05, p<.0001, I²=0%). There is no significant difference between adults with CF and controls in knee extensor strength (SMD = 0.25, p=.095, I²=42.79%).

CONCLUSIONS

Leg muscle atrophy and lower handgrip strength were noted. There may be a subgroup of adults with CF with knee extensor (quadriceps) weakness. Future studies are needed to better understand muscle impairments in people with CF; to explore the factors that can predict these muscle impairments; and to investigate their clinical significance in people with CF.

Lumacaftor/ivacaftor-associated health stabilisation in adults with severe cystic fibrosis

Introduction

Lumacaftor/ivacaftor (LUM/IVA) has been shown to improve clinical outcomes in cystic fibrosis (CF) patients homozygous for Phe508del with forced expiratory volume in 1 s (FEV₁) % pred >40%. We assessed the clinical utility of LUM/IVA in all eligible adult CF patients with FEV₁ % pred <40% treated for at least 1 year under a single-centre managed access programme.

Methods

Following clinical optimisation, eligible patients (n=40) with FEV₁ % pred <40% were commenced on LUM/IVA and monitored for tolerance and clinical outcomes, including health service utilisation, pulmonary function, weight and body composition. 24 patients reached 1 year of treatment by the time of evaluation. Six patients discontinued due to adverse events (five for increased airways reactivity) and three underwent lung transplantation.

Results

In comparison with the year prior to LUM/IVA commencement, significant reductions (median per year) were observed in the treatment year in the number of pulmonary exacerbations requiring hospitalisation (from 3 to 1.5; p=0.0002), hospitalisation days (from 27 to 17; p=0.0002) and intravenous antibiotic (IVAB) usage days (from 45 to 27; p=0.0007). Mean±sd change in FEV₁ % pred was −2.10±1.18% per year in the year prior, with the decline reversed in the year following (+1.45±1.13% per year; p=0.035), although there was significant heterogeneity in individual responses. Mean±sd weight gain at 1 year was 2.5±4.1 kg (p=0.0007), comprising mainly fat mass (mean 2.2 kg). The proportion of patients severely underweight (body mass index <18.5 kg·m⁻²) decreased from 33% at baseline to 13% at 1 year (p=0.003).

Conclusion

This real-world evaluation study demonstrated benefits over several clinical domains (infective exacerbations requiring hospitalisation, IVABs, pulmonary function decline and nutritional parameters) in CF patients with severe lung disease.

In adults with severe cystic fibrosis lung disease, 1 year of treatment with lumacaftor/ivacaftor was associated with reduced infective exacerbations, days of intravenous antibiotics and rate of pulmonary function decline, and improved nutritional statushttps://bit.ly/2I07suR

Body composition and weight changes after ivacaftor treatment in adults with cystic fibrosis carrying the G551 D cystic fibrosis transmembrane conductance regulator mutation: A double-blind, placebo-controlled, randomized, crossover study with open-label extension

OBJECTIVES

In patients with cystic fibrosis (CF) who carry the G551D mutation, treatment with ivacaftor improves lung function and weight; however, short- and long-term impacts on body composition have not been well studied.

METHODS

Twenty adults with CF carrying the G551D mutation (mean ± standard deviation body mass index [BMI] 23.3 ± 4.3 kg/m²) were recruited for a single-center, double-blind, placebo-controlled, 28-d, crossover study of ivacaftor, followed by an open-label extension (OLE) for 5 mo. Eleven patients underwent measurements 2 y later. The study variables included weight, BMI, and body composition (including fat-free mass [FFM] and fat mass).

RESULTS

After 28 d of treatment with ivacaftor, weight increased by 1.1 ± 1.3 kg, BMI by 0.4 ± 0.5 kg/m², and FFM by 1.1 ± 1.2 kg (all P < .005) with no change in fat mass. Differences between 28-d changes on ivacaftor and placebo were not statistically significant. In the following 5 mo of the OLE, there were significant increases in weight (1.2 ± 1.9 kg; P < .05) and fat mass (1.5 ± 1.9 kg; P < .01), but not in FFM. Between baseline and the end of the OLE, the total weight gain was 2.5 ± 2.4 kg (P < .005), comprised of 0.9 ± 1.5 kg FFM (P < .05) and 1.6 ± 1.8 kg fat mass (P < .005). For the 11 participants who were followed for a further 2 y, no further changes in mean weight, BMI, or body composition parameters between 6 mo and 2 y later were observed.

CONCLUSIONS

Small gains were seen in FFM in the first month of ivacaftor treatment. Weight, BMI, and fat-mass gains in the first 6 mo on ivacaftor plateaued by 2.5 y. The metabolic and clinical consequences of weight and fat-mass gains remain to be determined.

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.

Visceral adipose tissue is associated with poor diet quality and higher fasting glucose in adults with cystic fibrosis

BACKGROUND

Body fat distribution and diet quality influence clinical outcomes in general populations but are understudied in individuals with cystic fibrosis (CF). The aim of this pilot study was to assess body fat distribution and diet quality in relation to fasting glucose and lung function in adults with CF.

METHODS

Subjects were 24 adults (ages 18-50) with CF and 25 age-matched controls. The Healthy Eating Index 2015 (HEI-2015) was calculated from 3-day food records and data were adjusted per 1000 kcal. Whole and regional body composition, including visceral adipose tissue (VAT), was assessed by dual energy X-ray absorptiometry.

RESULTS

Subjects with CF reported more added sugar intake [26.1 (IQR 18.1) vs. 12.9 (12.5) g/1000 kcal, p < 0.001] and had lower HEI-2015 scores [48.3 (IQR 9.9) vs. 63.9 (27.3), p < 0.001] compared to controls. There were no differences in BMI, total body fat, or lean body mass (LBM) between subjects with CF and controls (p > 0.05 for all), although subjects with CF had higher VAT than control subjects [0.3 (IQR 0.3) vs 0.1 (0.3) kg, p = 0.02]. Among subjects with CF, VAT was positively associated with added sugar intake (p < 0.001) and fasting blood glucose (p = 0.04). Lung function was positively associated with BMI (p = 0.005) and LBM (p = 0.03) but not with adiposity indicators.

CONCLUSIONS

These novel data link body fat distribution with diet quality and fasting glucose levels in adults with CF, whereas LBM was associated with lung function. This study highlights the importance of increasing diet quality and assessing body composition and fat distribution in the CF population.

Improvement in body composition following a supervised exercise-training program of adult patients with cystic fibrosis

OBJECTIVES

Maintenance of optimal nutritional status is a crucial issue for cystic fibrosis (CF) patients. Here, we evaluate the effects of an 8-week exercise training (ET) program on body composition in CF patients.

METHODS

This prospective pilot observational study was conducted in adult CF subjects in stable condition following their annual check-up. The ET program consisted of three sessions per week and included aerobic training (≥30min), muscle strengthening, circuit training, and relaxation. Exercise tolerance (6-minute walk test, 6MWT), pulmonary function, quadriceps isometric strength, and body composition (bioelectrical impedance analysis of fat-free mass [FFM], fat mass, and body cell mass) were analyzed before and immediately after the ET program. A control group of CF patients who preferred not to participate in the ET program received the same evaluations.

RESULTS

A total of 43 CF patients were enrolled and offered the ET program; 28 accepted (aged 28±5 years, forced expiratory volume in 1s [FEV₁] 48.8±19% predicted) and 15 declined the ET program but agreed to be part of the control group (matched for age and CF severity: 30.8±9 years, FEV₁ 51.8±16.5%). Pulmonary function was unchanged at the end of the ET program, but significant improvements were observed in 6MWT distance (from 520±96m to 562±105m, P<0.001) and muscle strength (331±141N to 379±168N, P<0.001). Although mean body mass index did not change, the ET group showed significantly increased FFM (43.85±8kg to 44.5±9.2kg, P=0.03) and a trend towards increased body cell mass (21.4±6 to 22.1±6.6kg, P=0.06). All other parameters were unchanged by ET. There were no significant correlations between the increase in FFM and the improvements in either 6MWT distance or muscle strength. The CF control group exhibited no significant changes in any parameters between evaluations.

CONCLUSIONS

ET significantly improved FFM, but not body mass index, in CF patients. The results illustrate the superiority of bioimpedancemetry for assessing changes in body composition and reveal the importance of ET for improving not only exercise tolerance but also nutritional status in these patients.

Physical activity and associations with clinical outcome measures in adults with cystic fibrosis; a systematic review

BACKGROUND

Physical activity (PA) is important in the management of Cystic Fibrosis (CF) and is associated with a number of beneficial effects. PA assessment is not commonplace or consistent in clinical practice, therefore understanding of PA in adults with CF remains limited. The purpose of this review was to evaluate PA levels in this population and compare PA to global recommendations and non-CF peers.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were utilised to inform the review process. Original research was identified and screened against inclusion/exclusion criteria. Quality was assessed, data extracted and a narrative synthesis undertaken to describe the findings.

RESULTS

Adults with CF did not achieve recommended PA guidelines and step count targets in 5/8 studies where assessment was possible. No significant differences in PA were found between CF and non-CF peers in 3/5 studies. Associations between PA and improved lung function were inconsistent with 4/9 studies finding a positive association. Evidence for an association between PA and higher exercise capacity was stronger with all 4 studies reviewed reporting a positive association. Quality ratings were low across all studies.

CONCLUSIONS

PA in adults with CF is largely comparable to their non-CF peers, despite being insufficiently active to achieve PA recommendations. Assessment tools used and outcomes reported are variable, many of which do not provide sufficient information to assess relevant components of PA. There is a requirement for high quality studies designed specifically to explore PA in adults with CF, ideally employing standardised PA assessment methods.

THE USE OF ULTRASONOGRAPHY TO EVALUATE MUSCLE THICKNESS AND SUBCUTANEOUS FAT IN CHILDREN AND ADOLESCENTS WITH CYSTIC FIBROSIS

Objective:

To compare muscle thickness and subcutaneous fat in cystic fibrosis (CF) patients and healthy controls using ultrasonography (US), and to correlate US findings with nutritional, clinical and functional variables.

Methods:

Patients aged 6 to 18 years old with a diagnosis of CF and healthy controls were included. Participants underwent anthropometric measurements, an ultrasonographic evaluation of muscle thickness and subcutaneous fat in the triceps, quadriceps, and gastrocnemius regions, and skinfold thickness measurements. Body fat percentage was estimated using skinfold measurement. Subjects with CF also underwent a pulmonary function assessment using spirometry.

Results:

We studied 39 CF patients and 45 controls. Alower body mass index was observed in CF patients (p=0.011). Body composition and muscle thickness were similar between the groups. Only calf (p=0.023) circumference and femur diameter (p<0.001) were lower in CF patients. Although there were no significant between-group differences in the comparison of US measurements of subcutaneous fat, CF patients exhibited decreased skinfold thickness in the triceps (p=0.031) and quadriceps (p=0.019). Moreover, there were weak and moderate correlations of US quadricep thickness with forced vital capacity (FVC) and lean mass, respectively. Moderate correlations of the triceps, quadriceps and gastrocnemius between US subcutaneous fat and skinfold measurements were found.

Conclusions:

Patients with CF presented a reduction in subcutaneous fat content. Muscle thickness correlated with FVC and nutritional parameters. In addition, US findings correlated positively with skinfold measurements.

Protein Requirements of the Critically Ill Pediatric Patient

This article includes a review of protein needs in children during health and illness, as well as a detailed discussion of protein metabolism, including nitrogen balance during critical illness, and assessment and prescription/delivery of protein to critically ill children. The determination of protein requirements in children has been difficult and challenging. The protein needs in healthy children should be based on the amount needed to ensure adequate growth during infancy and childhood. Compared with adults, children require a continuous supply of nutrients to maintain growth. The protein requirement is expressed in average requirements and dietary reference intake, which represents values that cover the needs of 97.5% of the population. Critically ill children have an increased protein turnover due to an increase in whole-body protein synthesis and breakdown with protein degradation leading to loss of lean body mass (LBM) and development of growth failure, malnutrition, and worse clinical outcomes. The results of protein balance studies in critically ill children indicate higher protein needs, with infants and younger children requiring higher intakes per body weight compared with older children. Monitoring the side effects of increased protein intake should be performed. Recent studies found a survival benefit in critically ill children who received a higher percentage of prescribed energy and protein goal by the enteral route. Future randomized studies should evaluate the effect of protein dosing in different age groups on patient outcomes, including LBM, muscle structure and function, duration of mechanical ventilation, intensive care unit and hospital length of stay, and mortality.

Nutrition for Patients With Cystic Fibrosis

Cystic fibrosis (CF) is the most frequent, lethal genetic disorder among northern Europeans. The etiology of this autosomal recessive disease is known to be a defect in the cAMP activation of chloride (Cl-) channels in secretory cells in many organs of the body. Although this defect usually leads to severe lung disease, many of these patients also have nutritional deficiencies. Nutrition is one of the key components in the management of CF. Patients are at high risk for malnutrition, which may result in accelerated progression of the disease and increased morbidity. This review will discuss nutrition recommendations for calories, protein, vitamins and minerals, and enteral and parenteral nutrition support practices.

Body composition and lung function in cystic fibrosis and their association with adiposity and normal-weight obesity

OBJECTIVES

This study aimed to evaluate the relationship between lung function and body composition in cystic fibrosis (CF) and examine the presence of normal-weight obesity (NWO), a high body fat percentage with a normal body mass index (BMI), in this population.

METHODS

In a pilot, cross-sectional study, 32 subjects with CF and a reference group of 20 adults without CF underwent body composition analysis with air displacement plethysmography. NWO was defined as a BMI <25 kg/m(2) and body fat >30% (for women) or >23% (for men). Lung function in subjects with CF was determined by the percentage of predicted forced expiratory volume in 1 s (FEV1% predicted).

RESULTS

Despite lower BMI and fat-free mass index (P < 0.01), fat mass index and percent body fat did not differ between subjects with CF and the reference group. Among subjects with CF, FEV1% predicted was positively associated with fat-free mass index (β = 6.31 ± 2.93, P = 0.04) and inversely associated with fat mass index (β = -6.44 ± 2.93, P = 0.04), after adjusting for age, sex, and BMI. Ten subjects with CF (31%) had NWO, which corresponded with lower fat-free mass index and FEV1% predicted compared with overweight subjects (P = 0.006 and 0.004, respectively).

CONCLUSIONS

Excess adiposity, particularly in the form of NWO, was inversely associated with lung function in CF. Larger prospective studies should be undertaken to confirm these findings and determine the long-term metabolic and clinical consequences of excess adiposity in CF. As the lifespan of individuals with CF increases, nutrition screening protocols, which primarily rely on BMI, may require reassessment.

Body composition and pulmonary function in cystic fibrosis

BACKGROUND

Lower body mass index (BMI) is associated with worse pulmonary function in cystic fibrosis (CF).

HYPOTHESIS

lean body mass (LBM) is more strongly associated with pulmonary function than BMI is.

METHODS

Anthropometrics, body composition by dual x-ray absorptiometry, and pulmonary function were determined in pancreatic insufficient CF (PI-CF) youth. Sex and age-adjusted Z-scores (BMI-Z, LBMI-Z, FMI-Z) were generated for CF and controls. (1) Associations of BMI-Z with LBMI-Z and FMI-Z and (2) age-adjusted associations of BMI-Z, LBMI-Z, and FMI-Z with FEV1%-predicted were tested.

RESULTS

Two hundred eight PI-CF subjects had lower BMI-Z, LBMI-Z, and FMI-Z compared to 390 controls. BMI-Z was associated with lower LBMI-Z (p < 0.0001) in PI-CF. In females, LBMI-Z and BMI-Z were positively associated with FEV1%-predicted; this relationship did not persist for FMI-Z after adjustment for LBMI-Z. In males, only LBMI-Z and BMI-Z were associated with FEV1%-predicted.

CONCLUSION

In PI-CF youth, deficits in LBM were apparent. At lower BMI percentiles, BMI may not accurately depict LBM in PI-CF. In under-nourished PI-CF youth, this preservation of FM in preference to LBM is relevant since LBMI-Z, but not FMI-Z, is positively associated with FEV1%-predicted. Lean body mass index is more strongly associated with lung function compared to BMI, especially in the under-nourished child and adolescent with PI-CF.

New stable isotope method to measure protein digestibility and response to pancreatic enzyme intake in cystic fibrosis

BACKGROUND & AIMS

Adequate protein intake and digestion are necessary to prevent muscle wasting in cystic fibrosis (CF). Accurate and easy-to-use methodology to quantify protein maldigestion is lacking in CF.

OBJECTIVE

To measure protein digestibility and the response to pancreatic enzyme intake in CF by using a new stable isotope methodology.

DESIGN

In 19 CF and 8 healthy subjects, protein digestibility was quantified during continuous (sip) feeding for 6 h by adding (15)N-labeled spirulina protein and L-[ring-(2)H5]phenylalanine (PHE) to the nutrition and measuring plasma ratio [(15)N]PHE to [(2)H5]PHE. Pancreatic enzymes were ingested after 2 h in CF and the response in protein digestibility was assessed. To exclude difference in mucosal function, postabsorptive whole-body citrulline (CIT) production rate was measured by L-[5-(13)C-5,5-(2)H2]-CIT pulse and blood samples were taken to analyze tracer-tracee ratios.

RESULTS

Protein digestibility was severely reduced in the CF group (47% of healthy subjects; P < 0.001). Intake of pancreatic enzymes induced a slow increase in protein digestibility in CF until 90% of values obtained by healthy subjects. Maximal digestibility was reached at 100 min and maintained for 80 min. Stratification into CF children (n = 10) and adults showed comparable values for protein digestibility and similar kinetic responses to pancreatic enzyme intake. Whole-body citrulline production was elevated in CF indicating preserved mucosal function.

CONCLUSION

Protein digestibility is severely compromised in patients with CF as measured by this novel and easy-to-use stable isotope approach. Pancreatic enzymes are able to normalize protein digestibility in CF, albeit with a severe delay. Registration ClinicalTrials.gov = NCT01494909.

Changes in body composition after lung transplantation in children

BACKGROUND

The evaluation of nutritional status, including body composition measurements, in pediatric patients before and after lung transplant (LTx) can aid in adapting nutrition support and physical rehabilitation programs to meet individual patient needs. The purpose of this retrospective study was to determine the changes in weight, lean body mass (LBM), and body fat (BF) before and after LTx and their association with lung function in pediatric patients.

METHODS

Included were 41 LTx patients, aged 3 months to 20.7 years, who had at least 2 body composition measurements determined by dual-energy X-ray absorptiometry (GE Lunar Prodigy, Waukesha, WI) in the first 2 years after LTx were measured pre-LTX and at 12 or 24 months post-LTX, for weight, LBM, and BF.

RESULTS

Pre-LTx, 29% of patients had moderate and 12% had severe chronic malnutrition (growth stunting). This compares with 21% of patients being moderately LBM-depleted and 23% being BF-depleted. The weight change at 12 and 24 months was +9.3% (interquartile range, 5.6%-23%) and +4.7% (0.9%-11.6%), respectively; whereas the LBM change at 12 and 24 months was +15.2% (6.8%-17.1%) and +4.2% (-0.6% to 7.7%), respectively. LBM percentiles correlated with pulmonary function tests ( % predicted forced vital capacity [ρ = 0.36, p = 0.001] and forced expiratory volume in 1 second [ρ = 0.265, p = 0.015).

CONCLUSIONS

Maximum weight and LBM gain occur at 12 months after LTx, with smaller gains noted at 24 months. Clinicians must look beyond height and weight and evaluate LBM and fat mass in pediatric patients after LTx.

Systemic comorbidities in bronchiectasis

Bronchiectasis is a chronic inflammatory lung disease, which has similarities to chronic obstructive pulmonary disease (COPD). Comorbidities of COPD include increased risk of cardiovascular (CV) disease, loss of bone mineral density (BMD) and loss of skeletal muscle mass and function, all linked to systemic inflammation. The potential for such comorbidities has not been explored in bronchiectasis. We hypothesised that patients with bronchiectasis would have similar increased comorbidities. A total of 20 patients with noncystic fibrosis bronchiectasis were compared to 20 controls similar in age, gender and smoking exposure. Assessments included aortic pulse wave velocity (PWV; (a measure of arterial stiffness and an independent predictor of CV risk), blood pressure (BP) as well as levels of interleukin-6 (IL-6), albumin, fasting glucose and lipids. Body composition (fat free mass index (FFMI)), BMD, the 6-min walk distance (6MWD) and self-reported physical activity were also determined. Patients with bronchiectasis had increased aortic PWV, 10.5 (3.0) m/second, when compared with controls, 8.8 (1.6) m/second (p < 0.05), despite similar central and peripheral BP and lipid profile. Patients also had increased IL-6 and reduced albumin and glucose. Although mean body mass index, FFMI and BMD were similar in patients and controls, only 20% of patients had a healthy BMD compared with 50% of controls. Patients had reduced 6MWD and reported less physical activity (p < 0.05). Patients with bronchiectasis had increased arterial stiffness (an indicator of increased CV risk), increased inflammation, reduced exercise capacity and bone thinning. These additional comorbidities require further evaluation for their management in these patients.

Loss of fat-free mass over four years in adult cystic fibrosis is associated with high serum interleukin-6 levels but not tumour necrosis factor-alpha

BACKGROUND & AIMS

Malnutrition is associated with poorer outcome in cystic fibrosis (CF). This follow-up study aimed to document nutritional status changes, including fat-free mass (FFM), in adults with CF; and to identify predictors of FFM loss.

METHODS

Fifty-eight non-transplanted CF adults (mean ± SD forced expiratory volume in one second (FEV1) 63.7 ± 21.4%predicted; mean ± SD age 30.3 ± 7.7years at baseline) were studied at baseline and 3.6 ± 0.4 years later. Body composition was measured using dual-energy X-ray absorptiometry. At follow-up, blood was analysed for interleukin-6 and tumour necrosis factor-α (TNF-α) on three occasions over six months and averaged for each participant. Associations with annual percentage change in FFM (ann%ΔFFM), including cytokines, CF genotype and annual change in FEV1%predicted (annΔFEV1%), were determined.

RESULTS

Mean FFM was 49.5 ± 8.8 kg at baseline and 49.6 ± 8.9 kg at follow-up (p = 0.66). Ann%ΔFFM ranged from -2.0 to +3.6%. FEV1%predicted declined by 1.2 ± 2.4% per year. Forty percent of participants had elevated average interleukin-6 levels. Ann%ΔFFM was negatively correlated with interleukin-6 levels (rho -0.34, p = 0.008), but not TNF-α or annΔFEV1%. F508DEL homozygote or heterozygote participants had greater FFM loss than those carrying no F508DEL allele (p = 0.01).

CONCLUSION

Higher serum interleukin-6 and presence of the F508DEL mutation, but not TNF-α, were associated with FFM loss in adults with CF.

Measures of body habitus are associated with lung function in adults with cystic fibrosis: a population-based study

BACKGROUND

Body habitus differences may explain some of the variation in lung function between individuals with cystic fibrosis (CF). We tested the hypothesis that measures of lean muscle mass and obesity are independently associated with lung function in CF.

METHODS

Cross-sectional study design using UK CF registry data from 2096 clinically stable adults.

RESULTS

Serum creatinine and BMI were positively and independently associated with FEV1 and FVC. One standard deviation increment in serum creatinine was associated with an FEV1 increase of 171ml (95% confidence intervals CI: +116 to +227ml) in males and 90ml (95% CI: +46 to +133ml) in females. Compared to the reference group of 20-24.9kg/m(2), those with a BMI<20kg/m(2) had lower FEV1 with values of -642ml (95%CI: -784 to -500ml) for males and -468ml (95%CI: -564 to -372ml) for females.

CONCLUSIONS

Prospective studies and controlled trials are required to ascertain if these associations have therapeutic potential in modifying disease progression.

A multi-center controlled trial of growth hormone treatment in children with cystic fibrosis

OBJECTIVES

We evaluated safety and efficacy of recombinant human growth hormone (rhGH) for improving growth, lean body mass (LBM), pulmonary function, and exercise tolerance in children with cystic fibrosis (CF) and growth restriction.

STUDY DESIGN

Multicenter, open-label, controlled clinical trial comparing outcomes in prepubertal children <14 years with CF, randomized in a 1:1 ratio to receive daily rhGH (Nutropin AQ) or no treatment (control) for 12 months, followed by a 6-month observation (month 18). Safety was monitored at each visit, including assessments of glucose tolerance.

RESULTS

Sixty-eight subjects were randomized (control n = 32; rhGH n = 36). Mean height standard deviation score (SDS) in the rhGH group increased by 0.5 ± 0.4 at 12 months (mean ± SD, P < 0.001); the control group height SDS remained unchanged. Weight increased by 3.8 ± 1.8 versus 2.8 ± 1.5 kg, (mean ± SD, P = 0.0356) and LBM increased by 3.8 ± 1.8 versus 2.1 ± 1.4 kg (P = 0.0002) in the rhGH group versus controls, respectively. Forced vital capacity increased by 325 ± 319 in the rhGH group compared with 178 ± 152 ml in controls (mean ± SD, P = 0.032). Forced expiratory volume in 1 sec improved in both groups with a significant difference between groups after adjustment for baseline severity (LS mean ± SE: rhGH, 224 ± 37, vs. controls, 108 ± 40 ml; P = 0.04). There was no difference between groups in exercise tolerance (6-min walk distance) at 1 year. Changes in glucose tolerance for the two groups were similar over the 12-month study period, with three subjects developing IGT and one CFRD in each group. One rhGH-treated patient developed increased intracranial pressure.

CONCLUSIONS

Treatment with rhGH in prepubertal children with CF was effective in promoting growth, weight, LBM, lung volume, and lung flows, and had an acceptable safety profile.

Body composition assessed by the 4-component model and association with lung function in 6-12-y-old children with cystic fibrosis

BACKGROUND

Malnutrition is an indicator of a poor prognosis in patients with cystic fibrosis (CF). Previous body-composition (BC) studies in children with CF used 2-component models (2CMs) to assess fat mass (FM) and fat-free mass (FFM), but to our knowledge no study has used the gold-standard 4-component model (4CM), which allows for a more accurate evaluation of the nature of both elements.

OBJECTIVE

We measured BC by using the 4CM in 6-12-y-old children with CF to 1) compare findings with those of healthy, matched control children and reference data; 2) relate BC to lung spirometry [forced expired volume in 1 s (FEV₁)]; and 3) compare findings with those from more commonly used 2CM techniques.

DESIGN

One hundred clinically stable children with CF (57% girls) aged 6-12 y were measured by using the 4CM. Children with CF underwent spirometry (FEV₁).

RESULTS

Girls with CF had significantly less FM than did healthy girls, even after adjustment for height and pubertal status; boys with CF had higher body mass index SD scores than did healthy boys. FM in girls was positively associated with the FEV₁ percentage predicted. The 2CM FM was significantly different from the 4CM FM, with differences dependent on sex and condition, although most techniques identified a relation between FM and FEV₁ in girls.

CONCLUSIONS

Although shorter than healthy children, boys with CF were heavier and had a BC within the normal range; however, girls with CF had lower FM than did healthy girls, and this was associated with poorer lung function. Given the worse prognosis in girls, this finding merits more attention. The reliability of 2CM techniques varied with sex and health status.

Update on cystic fibrosis-related bone disease: a special focus on children

A high prevalence of low bone mineralization is documented in adult patients with cystic fibrosis (CF). Osteopenia is present in up to 85% of adult patients and osteoporosis in 10% to 34%. In children, study results are discordant probably because of comparisons to different control populations and corrections for bone size in growing children. Malnutrition, inflammation, vitamin D and vitamin K deficiency, altered sex hormone production, glucocorticoid therapy, and physical inactivity are well known risk factors for poor bone health. Puberty is a critical period for bone mineralization and requires a careful follow-up to achieve optimal bone peak mass. Strategies for optimizing bone health, such as monitoring bone mineral density (BMD) and providing preventive care are necessary from childhood through adolescence to minimize CF-related bone disease in adult CF patients.

Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: results of a systematic review

The Cystic Fibrosis Foundation established a process of systematic review of evidence to inform the development of clinical care guidelines and encourage evidence-based practice. The Subcommittee on Growth and Nutrition reviewed the evidence in two areas: energy intake and dosing for pancreatic enzyme replacement therapy. Evidence-based recommendations are presented here. Also, an ad hoc working group conducted a review of the literature and performed new analyses using the Cystic Fibrosis Foundation Patient Registry to update the recommendations for growth and weight-status monitoring. These Registry data-based recommendations are presented.

Chronic pediatric inflammatory diseases: effects on bone

In children, chronic inflammatory diseases present a significant challenge to long-term skeletal health. These conditions are often associated with poor appetite and suboptimal overall nutrition, altered nutrient utilization, delayed puberty, inactivity, and reduced muscle mass, all of which can alter bone metabolism. In addition, bone cell activity is susceptible to the effects of the immune response that characterizes these diseases. Moreover, drugs used to treat these maladies, notably glucocorticoids, may have negative effects on bone formation and on linear growth in developing children. As a result, predicted peak bone mass may not be achieved, and fracture risk may be increased in the short term or in the future. Studies using primarily dual energy X-ray absorptiometry have documented that deficits in bone mass are common in these diseases. However, there are wide variations in the prevalence of low bone mass, largely due to differences in the characteristics of each study population. Recent studies provide insight into the pathogenesis of decreased bone mass in these conditions. In this paper we will provide an overview of the effects of chronic inflammatory conditions on bone mass in children. We will also present relevant data from adult patients, when pediatric data are scant or not available.

Exercise during childhood and adolescence: a prophylaxis against cystic fibrosis-related low bone mineral density? Exercise for bone health in children with cystic fibrosis

Inadequate bone mineral accrual during growth and accelerated bone demineralisation in adulthood are recognised as additional and serious complications for patients with cystic fibrosis (CF). However, little attention has been given to preventative strategies for this population. Inadequate bone accrual during childhood and adolescence, and premature bone loss, lead to a failure to attain an optimal peak bone mass, osteoporosis and fracture in patients with CF. Pharmaceutical treatments may assist in the improvement of bone in patients with CF, but these are usually not preferable for use in children. Evidence indicates that regular, weight-bearing exercise significantly enhances bone accrual in healthy children. This paper reviews the literature concerning the potential for weight-bearing exercise to improve bone mineral accrual in children with CF. All relevant literature since 1979 was obtained and reviewed from the Medline, PubMed, Cochrane and PEDro data base. Evidence concerning the efficacy of exercise for bone health in CF is lacking. There have been no controlled trials investigating the value of weight-bearing exercise for bone accrual in children with CF. As exercise may offer an effective and enjoyable strategy to improve the bone development in children who have CF, exercise should be a high priority for randomised controlled trials in this population.

Plasma ghrelin and leptin in adult cystic fibrosis patients

BACKGROUND

Weight loss in cystic fibrosis (CF) may be associated with altered levels of appetite stimulating peptide ghrelin and the appetite decreasing peptide leptin. However, prior data on leptin in CF are conflicting, while the data on ghrelin are scarce. We hypothesized that weight loss in CF is associated with low levels ghrelin and elevated levels of leptin.

METHODS

Plasma ghrelin, leptin, TNF-alpha, IL-1 and IL-6, BMI, fat free mass (FFM), fat mass (FM) were measured in 74 CF adults and 20 controls. CF subjects were divided into 3 groups based on lung disease: mild (n=19), moderate (n=30) and severe (n=25).

RESULTS

Severe CF patients (% predicted FEV1 27+/-7; median BMI 21 kg/m2) had significantly elevated ghrelin and decreased leptin compared to controls and other CF subjects. Ghrelin correlated (r value, p value) with BMI (-0.35,<0.001), FFM (-0.22,<0.05), FM (-0.41,<0.0001), FEV1 (-0.62,<0.001), TNF-alpha (0.51,<0.0001), IL-1 (0.56,<0.0001), and IL-6 (0.33,<0.01). Leptin correlated (r value, p value) with BMI (0.40,<0.0001), FM (0.56,<0.0001), FEV1 (0.34,<0.05), IL-1 (-0.51,<0.05) and TNF-alpha (-0.43,<0.0001). BMI and FEV1 were independent predictors of ghrelin (-0.35,<0.05;-0.59,<0.001). FM was a predictor of leptin (0.56,<0.0001). Cytokines were elevated only in severe CF (severe CF vs. controls, pg/ml): TNF-alpha (3.4+/-0.6 vs. 1.2+/-0.4), IL-1 (3.5+/-1 vs. 0.2+/-0.1), IL-6 (17.4+/-4 vs. 2.4+/-2).

CONCLUSIONS

Elevated ghrelin and decreased leptin levels are a consequence rather than a cause of weight loss in advanced CF.