Role of exercise and nutrition status on bone mineral density in cystic fibrosis

Treatment of cystic fibrosis related bone disease

The advent of highly effective CFTR modulator therapies has slowed the progression of pulmonary complications in people with cystic fibrosis. There is increased interest in cystic fibrosis bone disease (CFBD) due to the increasing longevity of people with cystic fibrosis. CFBD is a complex and multifactorial disease. CFBD is a result of hypomineralized bone leading to poor strength, structure and quality leading to susceptibility to fractures. The development of CFBD spans different age groups. The management must be tailored to each group with nuance and based on available guidelines while balancing therapeutic benefits to risks of long-term use of bone-active medication. For now, the mainstay of treatment includes bisphosphonates. However, the long-term effects of bisphosphonate treatment in people with CF are not fully understood. We describe newer agents available for osteoporosis treatment. Still, the lack of data behooves trials of monoclonal antibodies treatments such as Denosumab and Romozosumab and anabolic bone therapy such as teriparatide and Abaloparatide. In this review, we also summarize screening and non-pharmacologic treatment of CFBD and describe the various options available for the pharmacotherapy of CFBD. We address the prospect of CFTR modulators on bone health while awaiting long-term trials to describe the effects of these medications on bone health.

Peripheral muscle strength is associated with aerobic fitness and use of antibiotics in patients with cystic fibrosis

AIMS

Individuals with cystic fibrosis (CF) may develop muscle abnormalities, although little is known on its clinical and functional impact. This study aimed to evaluate the association of peripheral muscle strength with aerobic fitness, habitual physical activity, lung function and the use of antibiotics (ATB) in patients with CF.

METHODS

A cross-sectional study where individuals aged ≥6 years underwent peripheral muscle strength evaluation (biceps, quadriceps and hamstrings) and performed a cardiopulmonary exercise test. Demographic, anthropometric, genetic, lung function and total days of ATB use within 1 year of tests were also collected.

RESULTS

Correlation was found for biceps (r = .45; P = .002) strength with the peak oxygen consumption (VO₂ peak). Muscle strength (biceps and quadriceps) also correlated with the ventilatory equivalent for oxygen consumption (V_E /VO₂ ) at anaerobic threshold (AT) and with the ventilatory equivalent for carbon dioxide production (V_E /VCO₂ ) both at AT and peak exercise. Negative correlations were found for quadriceps (r = -.39) and hamstrings (r = -.42) with the total days of ATB use in the following year. Patients needing to use ATB presented lower biceps strength (P = .05) and individuals with VO₂ peak lower than 37 mL·kg^-1 ·min^-1 presented lower muscle strength for both biceps (P = .01) and quadriceps (P = .02).

CONCLUSIONS

The results have shown that peripheral muscle strength is associated with aerobic fitness and the use of antibiotics in patients with CF.

Cystic fibrosis bone disease treatment: Current knowledge and future directions

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

The role of daily physical activity and nutritional status on bone turnover in cystic fibrosis: a cross-sectional study

BACKGROUND

Nutritional status and daily physical activity (PA) may be an excellent tool for the maintenance of bone health in patients with cystic fibrosis (CF).

OBJECTIVE

To evaluate the relationship between nutritional status, daily physical activity and bone turnover in cystic fibrosis patients.

METHOD

A cross-sectional study of adolescent and adult patients diagnosed with clinically stable cystic fibrosis was conducted. Total body, femoral neck, and lumbar spine bone mineral density (BMD) were determined by dual energy X-ray absorptiometry and bone metabolism markers ALP, P1NP, PICP, and ß-CrossLaps. PA monitoring was assessed for 5 consecutive days using a portable device. Exercise capacity was also determined. Serum 25-hydroxyvitamin D and vitamin K were also determined in all participants.

RESULTS

Fifty patients (median age: 24.4 years; range: 16-46) were included. BMI had positive correlation with all BMD parameters, with Spearman's coefficients ranging from 0.31 to 0.47. Total hip bone mineral density and femoral neck BMD had positive correlation with the daily time spent on moderate PA (>4.8 metabolic equivalent-minutes/day; r=0.74, p<0.001 and r=0.72 p<0.001 respectively), daily time spent on vigorous PA (>7.2 metabolic equivalent-minutes/day; r=0.45 p<0.001), body mass index (r=0.44, p=0.001), and muscle mass in limbs (r=0.41, p=0.004). Levels of carboxy-terminal propeptide of type 1 collagen were positively associated with the daily time spent on moderate (r=0.33 p=0.023) and vigorous PA (r=0.53, p<0.001).

CONCLUSIONS

BMI and the daily time spent on moderate PA were found to be correlated with femoral neck BMD in CF patients. The association between daily PA and biochemical markers of bone formation suggests that the level of daily PA may be linked to bone health in this patient group. Further research is needed to confirm these findings.

Body composition and lung function in children with cystic fibrosis and meconium ileus

The aim of this study was to explore whether history of meconium ileus (MI) at birth in children and adolescents with cystic fibrosis (CF) adversely affects body composition and lung function in later life. Data of children and adolescents with CF who underwent spirometry and DXA as part of their routine care were analyzed. Associations between MI (explanatory variable) and areal bone mineral density (total body less head-TBLH aBMD), lean tissue mass (LTM), and fat mass (FM) (outcomes) were assessed using general linear models. Potential relationships of TBLH aBMD, LTM, and FM with FEV₁ (additional outcome) were also explored. One hundred and one subjects with CF (mean age 14 ± 3 years) were included, 19 (18.8%) of whom had history of MI. Negative associations were demonstrated between history of MI and FEV₁ (P = 0.04), TBLH aBMD (P = 0.03), and FM (P < 0.01) but not between history of MI and LTM (P = 0.07) after adjustment for other variables. Lung function was positively associated with TBLH aBMD (P < 0.01) and LTM (P = 0.02) but not with FM (P = 0.20).

CONCLUSION

Among children and adolescents with CF, those with history of MI have lower bone mineral density, FM, and lung function. What is Known: • Among children and adolescents with cystic fibrosis, those with history of meconium ileus in the neonatal period are at risk of having lower body mass index percentile and FEV ₁ percent predicted. What is New: • Children and adolescents with cystic fibrosis and history of meconium ileus have decreased bone mineral density and fat mass compared to patients without such history. • Lower lung function in children with MI coexists with suboptimal bone mineral density.

Young adults with cystic fibrosis have altered trabecular microstructure by ITS-based morphological analysis

Young adults with cystic fibrosis have compromised plate-like trabecular microstructure, altered axial alignment of trabeculae, and reduced connectivity between trabeculae that may contribute to the reduced bone strength and increased fracture risk observed in this patient population.

INTRODUCTION

The risk of fracture is increased in patients with cystic fibrosis (CF). Individual trabecular segmentation (ITS)-based morphological analysis of high-resolution peripheral quantitative computed tomography (HR-pQCT) images segments trabecular bone into individual plates and rods of different alignment and connectivity, which are important determinants of trabecular bone strength. We sought to determine whether alterations in ITS variables are present in patients with CF and may help explain their increased fracture risk.

METHODS

Thirty patients with CF ages 18-40 years underwent DXA scans of the hip and spine and HR-pQCT scans of the radius and tibia with further assessment of trabecular microstructure by ITS. These CF patients were compared with 60 healthy controls matched for age (±2 years), race, and gender.

RESULTS

Plate volume fraction, thickness, and density as well as plate-plate and plate-rod connectivity were reduced, and axial alignment of trabeculae was lower in subjects with CF at both the radius and the tibia (p < 0.05 for all). At the radius, adjustment for BMI eliminated most of these differences. At the tibia, however, reductions in plate volume fraction and number, axially aligned trabeculae, and plate-plate connectivity remained significant after adjustment for BMI alone and for BMI and aBMD (p < 0.05 for all).

CONCLUSIONS

Young adults with CF have compromised plate-like and axially aligned trabecular morphology and reduced connectivity between trabeculae. ITS analysis provides unique information about bone integrity, and these trabecular deficits may help explain the increased fracture risk in adults with CF not accounted for by BMD and/or traditional bone microarchitecture measurements.

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.

Exercise as part of a cystic fibrosis therapeutic routine

The role of exercise in cystic fibrosis (CF) is well established, and over the last three decades it has become an important component in the management of all individuals with CF. The role of exercise as a prognostic indicator or therapeutic tool is an important area of research interest in CF care internationally. This article summarizes the currently available evidence regarding exercise capacity in CF, the potential effects of exercise on health outcomes in CF and the challenges faced when trying to incorporate exercise into a CF therapeutic routine, and highlights some methods to facilitate the incorporation of exercise into CF therapeutic routines.

The role of exercise in maintaining health in cystic fibrosis

PURPOSE OF REVIEW

Consensus statements about the care of people with cystic fibrosis (CF) recommend exercise as part of a wider management strategy. Many of these recommendations are based on high-quality evidence that regular exercise improves some important clinical outcomes, such as lung function and quality of life. However, the evidence about the effect of exercise on other clinical outcomes is less extensive or lower in quality. This article will review the physiological effects of exercise on a range of outcomes in people with CF, the mechanisms by which exercise may improve these outcomes and the quality and findings of clinical research into the effects of exercise in the management of CF.

RECENT FINDINGS

Substantial evidence confirms that exercise significantly reduces the rate of decline in lung function in people with CF, at least in part by increasing mucus clearance. Regular exercise training over 6 months improves aerobic exercise capacity. Bone health is often poor in people with CF, but only indirect evidence supports that increasing the amount of exercise will have a beneficial effect on bone density. CF-related diabetes is also a common sequela of the disease, but again only evidence from type-2 diabetes exists to support exercise as a way of managing it.

SUMMARY

Although its effects on some outcomes are unclear, the overall effect of exercise on quality of life is substantially beneficial and the evidence available for other specific outcomes is directly or indirectly supportive, so it appears appropriate to recommend it in clinical practice.

A roadmap to the brittle bones of cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive disorder which despite advances in medical care continues to be a life-limiting and often fatal disease. With increase in life expectancy of the CF population, bone disease has emerged as a common complication. Unlike the osteoporosis seen in postmenopausal population, bone disease in CF begins at a young age and is associated with significant morbidity due to fractures, kyphosis, increased pain, and decreased lung function. The maintenance of bone health is essential for the CF population during their lives to prevent pain and fractures but also as they approach lung transplantation since severe bone disease can lead to exclusion from lung transplantation. Early recognition, prevention, and treatment are key to maintaining optimal bone health in CF patients and often require a multidisciplinary approach. This article will review the pathophysiology, current clinical practice guidelines, and potential future therapies for treating CF-related bone disease.

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.

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

AIM

To investigate bone mineral status in young cystic fibrosis (CF) patients and determine risk factors related with the development of low bone mineral density (BMD).

METHODS

We determined, in 81 patients with CF, 4 to 23-years-old, BMD as well as factors, which are thought to play a role in the development of reduced BMD.

RESULTS

BMD Z-score was between -1 and -2.5 in 27 (33%) and lower than -2.5 in 9 (11%). Means of BMD Z-score were lower than the expected value of 0 in the three groups of children, adolescents and young adults (P = 0.004; P < 0.001; P = 0.048, respectively), but they did not differ among them (P = 0.114). Analysis showed that Shwachman-Kulczycki (SK) score, gender and levels of 25-hydroxy-vitamin D were significant predictors of BMD Z-score. Significant also was the interaction between gender and SK score.

CONCLUSIONS

Our study supports that BMD may be reduced from a young age in CF patients though this needs to be confirmed using true volumetric measures of BMD. This defect is related to disease severity with males being more vulnerable. Inefficient levels of vitamin D are very common and contribute significantly to impaired bone health. The latter finding underlines the need for higher supplementation doses.

Bone mineral density in cystic fibrosis: benefit of exercise capacity

The aim of this study was to evaluate the association between bone mineral density (BMD) and objective maximal exercise measurements in adults with cystic fibrosis (CF). Twenty-five CF patients (19 males, 6 females, mean age 25.5 yr, range: 17-52) underwent BMD assessment and maximal-cycle ergometer exercise testing. We examined the relationship between gas exchange (% peak-predicted O(2) uptake, CO(2) output, O(2) saturation), exercise performance (maximum power, exercise duration), and respiratory mechanics (tidal volume, rate) with lumbar spine and total proximal femur BMD. The strongest clinical correlate with BMD was forced expiratory volume at 1s (lumbar spine Z-score, r=0.36; total proximal femur Z-score, r=0.68, p<0.01). The strongest exercise correlate was % peak-predicted O(2) uptake (lumbar spine Z-score, r=0.44, p<0.01; total proximal femur Z-score, r=0.59, p<0.01). There was a closer association between exercise parameters and total proximal femur BMD (r=0.43-0.60) than with lumbar spine BMD (r=0.04-0.45). Multiple regression analysis revealed VO(2) to be the strongest independent predictor of BMD (R(2)=0.86, p<0.001) followed by petCO(2) and body mass index (R(2)=0.7 and 0.5, respectively, p<0.01). Exercise appears to influence total proximal femur BMD more than lumbar spine BMD in CF. Exercise rehabilitation programs focusing on peripheral strength training may benefit those CF patients with low total proximal femur BMD.

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.

Fenretinide prevents the development of osteoporosis in Cftr-KO mice

BACKGROUND

The most recently described phenotype associated with Cystic Fibrosis (CF) is reduced bone mineral density which results in osteopenia and osteoporosis. The etiology of the early onset of osteoporosis in CF patients has remained to be established. It has been suggested that inadequate nutritional absorption of essential fatty acids may play a role in the altered bone metabolism. In this study, we characterized the protective effect of fenretinide [N-(4-hydroxyphenyl) retinamide], a vitamin A derivative, on the early onset of osteoporosis in cystic fibrosis transmembrane conductance regulator knockout (Cftr-KO) mice.

METHODS

Using micro-computed-tomography we examined the effect of fenretinide on the bone composition and architecture in a Cftr-KO mouse model which was then confirmed with histological analyses. Plasma fatty acids were quantified using thin layer chromatography-ELISA method.

RESULTS

Twice-weekly treatments with fenretinide, over four weeks dramatically increased trabecular bone volume compared to controls. This increase in bone volume was also related to an increased concentration of ceramide in the plasma resulting in the down regulation of phospholipid-bound AA in Cftr-KO mice.

CONCLUSIONS

To our knowledge, this is the first time that fenretinide's protective effect against osteoporosis has been demonstrated. The results of this study strongly suggest that fenretinide has potential to be used as a prophylaxis by preventing the early onset of osteoporosis.

Exercício aeróbico, treinamento de força muscular e testes de aptidão física para adolescentes com fibrose cística: revisão da literatura

São reconhecidos os benefícios da prática do exercício físico regular para pacientes com fibrose cística. Entretanto, poucos estudos envolvem pacientes adolescentes. O objetivo deste artigo foi revisar os efeitos da prática regular de exercícios aeróbicos e de força e resistência muscular para adolescentes com fibrose cística. Os principais testes de aptidão física para esta faixa etária e a importância deles para melhora do prognóstico e tratamento da doença também foram avaliados. As informações foram coletadas a partir de livro-texto e artigos publicados na literatura nacional e estrangeira nas seguintes bases de dados: LILACS, MEDLINE/PubMed, Biblioteca Cochrane e SciELO, abrangendo o período de 1994 a 2004. Foram utilizados os termos "exercise" e "cystic fibrosis" para seleção dos artigos. Esta pesquisa demonstrou que a prática de exercício aeróbico e treinamento de força muscular melhoram a desobstrução da árvore brônquica, diminuem a queda progressiva da função pulmonar, aumentam a massa muscular e a resistência ao exercício, promovem o desenvolvimento ósseo e melhoram a auto-estima e a qualidade de vida. Os melhores resultados foram obtidos com os programas de treinamento assistido, devido a sua maior regularidade.

Docosahexaenoic acid is associated with endosteal circumference in long bones in young males with cystic fibrosis

In children, but not adults with cystic fibrosis (CF), associations between essential fatty acids (FA) and bone mass have been reported. Low bone mineral density (BMD) is common in these patients. Previously we found a normal annual increase of BMD, suggesting a potential for attaining normal bone mass. The aim of the present study was to investigate phospholipid FA pattern in relation to bone in young adult men with CF compared with healthy controls. Fourteen male patients with CF were compared with forty-two healthy controls, using dual-energy X-ray absorptiometry for total bone, lumbar spine and femur and peripheral quantitative computerised tomography for tibia and radius. A questionnaire concerning physical activity and nutrition was used. FA in serum phospholipids were measured using capillary GLC. CF patients did not differ in physical activity and anthropometry from controls. There were no differences in bone parameters between the two groups, but patients chronically colonised withPseudomonas aeruginosahad lower BMD than non-colonised patients. The trabecular BMD in the tibia differed between patients and controls, but not after adjustment for age and weight. The endosteal circumference of the radius was significantly associated with serum phospholipid concentration of DHA and inversely with then-6:n-3 FA ratio in CF patients but not in controls. The present study showed that young physically active adult males with classical CF obtained similar bone mass as controls, although influenced by pseudomonas colonisation. The association between DHA and long bone endosteal circumference suggested a later peak bone mass in those with CF compared with controls.

The genetic background of osteoporosis in cystic fibrosis: Association analysis with polymorphic markers in four candidate genes

BACKGROUND

Reduced Bone Mass Density (BMD) is frequent in Cystic Fibrosis (CF). Potentially, other genes than the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene may contribute to the bone phenotype variability in CF patients.

METHODS

Four candidate genes likely associated with BMD variability were studied: the vitamin D receptor (VDR) gene, the estrogen receptor alpha (ESR1), the calcitonin receptor (CALCR) and the type I alpha 1 collagen (COL1A1) gene. A complete bone and CF evaluation was obtained for 82 subjects (39 m, 43 f): 15 had normal BMD (group 1), 46 were osteopenic (group 2), and 21 were osteoporotic (group 3).

RESULTS

No statistical difference was found among the three groups for age, sex, pancreatic status, and vertebral fractures, nor for any of the biochemical markers. Weight, Body Mass Index (BMI), and FEV1, scored significantly worse in the two groups with the lowest T score. The CFTR mutations R1162X and F508del were more frequent in patients with lower BMD (p=0.044 and p=0.071). There was no significant difference in the distribution of the five marker genotypes among the 3 groups defined according to the unadjusted or adjusted (BMI and FEV1) BMD T score. No significant correlation was found between the VDR, CALCR, or COL1A1 gene polymorphisms and reduced BMD values. The individual ESR1 PvuII-XbaI haplotype C-A is associated to elevated u-calcium levels whereas the haplotype T-A is associated to lower values (p=0.00251).

CONCLUSIONS

There was no evidence that the genes under study, with the possible exception of ESR1 gene variants, may modulate bone phenotype in CF.

Cystic fibrosis: nutritional consequences and management

Life expectancy for patients with Cystic Fibrosis (CF) has steadily improved during the last three decades, and death in childhood is now uncommon. Nutrition is a critical component of the management of CF, and nutritional status is directly associated with both pulmonary status and survival. Expert dietetic care is necessary, and attention must be given to ensuring an adequate energy intake in the face of demands which may be increased by inadequately controlled malabsorption, chronic broncho-pulmonary colonisation by bacteria and fungi, exacerbations of acute lung infection, impaired lung function, and the need for rehabilitation, repair and growth. Pancreatic enzyme replacement therapy (PERT) is needed by up to 90% of CF patients in Northern Europe, where the 'severe' mutation deltaF508 predominates, but a smaller proportion in Mediterranean countries and elsewhere, because pancreatic insufficiency is one of few features of CF which correlate with genotype. Complications of CF including liver disease and CF-related diabetes pose further challenges. In addition, deficiency of specific nutrients including fat soluble vitamins (particularly A, E and K) essential fatty acids and occasionally minerals occur for a variety of reasons. Osteopenia is common and poorly understood. Liver disease increases the likelihood of vitamin D deficiency. Glucose intolerance and diabetes affect at least 25% of CF adults, and the diabetes differs from both types 1 and 2 diabetes mellitus, but it inversely correlates with prognosis. Management consists of anticipating problems and addressing them vigorously as soon as they appear. Supplements of vitamins are routinely given. Energy supplements can be oral, enteral or, rarely, parenteral. All supplements, including PERT, are adjusted to individual needs.