A prospective study of change in bone mineral density over one year in adults with cystic fibrosis

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

The Effects of Ivacaftor on Bone Density and Microarchitecture in Children and Adults with Cystic Fibrosis

CONTEXT

Cystic fibrosis (CF) transmembrane conductance (CFTR) dysfunction may play a role in CF-related bone disease (CFBD). Ivacaftor is a CFTR potentiator effective in improving pulmonary and nutritional outcomes in patients with the G551D-CFTR mutation. The effects of ivacaftor on bone health are unknown.

OBJECTIVE

To determine the impact of ivacaftor on bone density and microarchitecture in children and adults with CF.

DESIGN

Prospective observational multiple cohort study.

SETTING

Outpatient clinical research center within a tertiary academic medical center.

PATIENTS OR OTHER PARTICIPANTS

Three cohorts of age-, race-, and gender-matched subjects were enrolled: 26 subjects (15 adults and 11 children) with CF and the G551D-CFTR mutation who were planning to start or had started treatment with ivacaftor within 3 months (Ivacaftor cohort), 26 subjects with CF were not treated with ivacaftor (CF Control cohort), and 26 healthy volunteers.

INTERVENTIONS

All treatments, including Ivacaftor, were managed by the subjects' pulmonologists.

MAIN OUTCOME MEASURES

Bone microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT), areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) and bone turnover markers at baseline, 1, and 2 years.

RESULTS

Cortical volume, area, and porosity at the radius and tibia increased significantly in adults in the Ivacaftor cohort. No significant differences were observed in changes in aBMD, trabecular microarchitecture, or estimated bone strength in adults or in any outcome measures in children.

CONCLUSIONS

Treatment with ivacaftor was associated with increases in cortical microarchitecture in adults with CF. Further studies are needed to understand the implications of these findings.

Adrenal function in cystic fibrosis

Cystic fibrosis (CF) is not known to directly affect the adrenal gland, but commonly used CF therapies do impact the function of the hypothalamic-pituitary-adrenal (HPA) axis. By binding to the glucocorticoid receptor, medications such as inhaled and oral corticosteroids can enhance the systemic effects of cortisol and result in iatrogenic Cushing syndrome. Prolonged use suppresses the body's ability to make cortisol, resulting in iatrogenic adrenal insufficiency upon medication discontinuation. Chronic use of inhaled and oral corticosteroids can negatively affect bone health, growth, and glucose metabolism. This chapter provides practical guidelines regarding the screening, diagnosis, and treatment of iatrogenic adrenal insufficiency. As the guidelines are mainly derived from the asthma literature, this chapter also highlights the need for studies to evaluate the impact of CF therapies on adrenal function and other CF-endocrinopathies.

Markers of bone turnover are reduced in patients with CF related diabetes; the role of glucose

BACKGROUND

Cystic fibrosis(CF) related diabetes(CFRD) and osteoporosis are prevalent in adult patients with CF. We aimed to evaluate if CFRD and markers of glucose metabolism and inflammation are associated with bone turnover in CF.

METHODS

Cross sectional study at the adult section at the Copenhagen CF Center from January-October 2017. Fasting blood samples, including bone turnover markers(BTMs) and cytokines, Dual-x-ray absorptiometry scan and oral glucose tolerance test were performed. Lung-transplanted participants and patients in antiosteoporotic treatment were excluded from analyses.

RESULTS

102 patients were included of whom 19 had a prior CFRD diagnosis. CFRD patients had lower procollagen type 1 N-terminal propeptide(P1NP) and C-Terminal cross-linked Telopeptide(CTX) levels compared to CF patients without diabetes (median[IQR]) 49.5 μg/l [29.6,57.1] vs 56.9 μg/l [38.2,74.3], p = .03 and 0.2 μg/l [0.1,0.3] vs 0.4 μg/l [0.3,0.6], p < .01, respectively. Fasting plasma glucose(FPG) was negatively associated with the bone formation markers P1NP and osteocalcin and bone resorption marker CTX. In multivariate linear regression FPG remained a significant predictor of P1NP -1.07 [-1.09;-0.01] and CTX -1.13 [-1.21;-1.06]. Bone mineral density Z-score was not different between patients with and without CFRD but FPG was negatively associated with hip and femoral neck Z-score. There was no consistent association between inflammatory cytokines and BTMs.

CONCLUSIONS

Bone turnover markers are reduced in CF patients with CFRD and negatively associated with glucose levels. Extra attention towards frequent hyperglycemia in CF patients should be taken when evaluating decreased BMD. Glycemia may be a future target for improving outcome in 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.

Gender Differences in Clinical Presentations of Cystic Fibrosis Patients in Azeri Turkish Population

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive disorder with several clinical presentations. This study was undertaken in the Azeri Turkish population in Iran, to investigate gender differences in the age at onset and diagnosis, age of death, and duration of illness of CF.

METHODS

The data of 331 CF patients from 2001 to 2015 was surveyed. Parameters including age, sex, ΔF508 mutation, age at onset, age at diagnosis, age of death and clinical presentations were evaluated for both sexes, using descriptive analysis. The association of gender with these variables was studied using logistic regression, chi-square test and Mann-Whitney U test by SPSS version 18. Odds ratio with a confidence interval of 95% and p≤0.05 was considered statistically significant.

RESULTS

The study included 191 males (57.7%) and 140 females (42.3%), all showing statistically significant difference (p<0.001). Age duration differed between genders. Male and female patients were further under 9 and 4 years, respectively. The occurrence of ΔF508 mutation was 0.51 times more in females than in males. Age, diagnosis and sex were closely associated: males were diagnosed at a significantly later age than females (p=0.05). While this compression performed based on clinical presentations, males with respiratory disease had a later median age at diagnosis than females at lifespan (p=0.001). The risk of infertility in males was approximately two times greater than in females (p=0.02).

CONCLUSION

These findings indicate gender differences in CF patients. Future studies are needed to establish other differences and evaluate the causes for the gender variations.

Bone health and disease in cystic fibrosis

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

Cystic fibrosis-related bone disease in children: Examination of peripheral quantitative computed tomography (pQCT) data

BACKGROUND

The investigation of skeletal health data beyond dual X-ray absorptiometry (DXA) is limited in young individuals with CF. We assessed volumetric bone mineral densities (BMD), and bone and muscle parameters using peripheral quantitative computed tomography (pQCT) in individuals with CF and controls, 7.00-17.99 years.

METHODS

Peripheral QCT (XCT 3000, Stratec) measurements were made in 53 individuals with CF and 53 controls. Bone mineral content (BMC), total volumetric BMD (vBMD) and cross sectional area (CSA) of the bone were measured at the 4% and 66% sites of the non-dominant tibia and radius. Additionally, trabecular vBMD and bone strength index (BSIc) were measured at the 4% sites, and cortical vBMD, muscle CSA (mCSA) and strength strain index (SSI) were measured at the 66% sites.

RESULTS

Pre-pubertal males with CF had greater trabecular vBMD (p=0.01) and total vBMD (p=0.00) at 4% tibia, and greater total vBMD (p=0.02) at 4% radius. Pre-pubertal females with CF had greater total vBMD at 66% tibia (p=0.02) and radius (p=0.04), and cortical vBMD (p=0.04) at the radius. At puberty, the CF cohort had less BMC at 4% tibia (males, p=0.02; females, p=0.01), and smaller mCSA at 66% tibia (males, p=0.02; females, p=0.01). Pubertal CF females had a smaller bone CSA (p=0.01) at 4% tibia, and lower bone strength (SSI) at the tibia (p=0.00) and radius (p=0.05) sites.

CONCLUSIONS

Bone strength parameters were not compromised prior to puberty in this CF cohort. At puberty, the bone phenotype changed for this CF cohort, showing several deficits compared to the controls. However, bone strength was adapting to the mechanical demands of the muscle. Altered bone parameters and their implications for lowered bone strength with increased age may be greatly influenced by: the CF cohort remaining smaller for age and/or a reduced bone strain, secondary to reduced muscle force.

Compromised bone microarchitecture and estimated bone strength in young adults with cystic fibrosis

CONTEXT

Young adults with cystic fibrosis (CF) are at risk for low bone density and fractures, but the underlying alterations in bone microarchitecture that may contribute to their increased fracture risk are currently unknown.

OBJECTIVE

The main goal of this study was to use high-resolution peripheral quantitative computed tomography (HR-pQCT) to characterize the bone microarchitecture, volumetric bone mineral density (vBMD), and estimated strength of the radius and tibia in young adults with CF compared with healthy volunteers.

DESIGN AND SETTING

This was a cross-sectional study at an outpatient clinical research center within a tertiary academic medical center.

PARTICIPANTS

Thirty young adults with CF, 18 to 40 years of age, were evaluated and compared with 60 healthy volunteers matched by age (±2 years), gender, and race.

MAIN OUTCOME MEASURES

The primary outcomes were HR-pQCT-derived cortical and trabecular vBMD, bone microarchitecture, and estimates of bone strength.

RESULTS

At the radius and tibia, young adults with CF had smaller bone cross-sectional area and lower vBMD. Cortical and trabecular microarchitecture were compromised at both sites, most notably involving the trabecular bone of the tibia. These differences translated into lower estimated bone strength both at the radius and tibia. After accounting for body mass index differences, young adults with CF had lower bone area and estimated bone strength at the radius and had compromised trabecular microarchitecture and lower total and trabecular vBMD and estimated bone strength at the tibia. Alterations in trabecular bone density and microarchitecture and estimated strength measures of the tibia were also greater than expected based on dual-energy x-ray absorptiometry-derived areal BMD differences.

CONCLUSIONS

Young adults with CF have compromised bone microarchitecture and lower estimated bone strength at both the radius and tibia, even after accounting for their smaller body size. These skeletal deficits likely explain the higher fracture risk observed in young adults with CF.

Vitamin D and chronic lung disease: a review of molecular mechanisms and clinical studies

Vitamin D is classically recognized for its role in calcium homeostasis and skeletal metabolism. Over the last few decades, vitamin D deficiency has increased in prevalence in adults and children. Potential extraskeletal effects of vitamin D have been under investigation for several diseases. Several cross-sectional studies have associated lower vitamin D status with decreased lung function. This finding has prompted investigators to examine the association of vitamin D deficiency with several chronic lung diseases. One major focus has been the link between maternal vitamin D status and childhood asthma. Vitamin D deficiency has also been associated with increased risk of respiratory infection from influenza A and Mycobacterium tuberculosis. Other chronic respiratory diseases associated with vitamin D deficiency include cystic fibrosis, interstitial lung disease, and chronic obstructive pulmonary disease. This review will examine the current clinical literature and potential mechanisms of vitamin D in various pulmonary diseases.

Provision of contraception services and advice for women with cystic fibrosis

BACKGROUND AND METHODOLOGY

As the prognosis of patients with cystic fibrosis (CF) improves, issues of sexual health, fertility, pregnancy and contraception are increasingly important. In order to plan the provision of a contraception and sexual health service for women with CF we studied their sexual and reproductive history, their current usage of contraception, the sources and quality of advice they had received, and their particular needs using a confidential questionnaire sent to all women over 16 years of age attending a regional CF centre.

RESULTS

Of 55 women (mean age 29.7 years) surveyed, 42 (76%) responded. Thirty-three women (79%) were sexually active and 13 (31%) had experienced 19 pregnancies, five (26%) of which were unplanned. Only half of the women who responded were using contraception. No woman used female sterilisation, the progestogen implant, intrauterine system (IUS) or copper-bearing intrauterine device (IUD) for contraception. Twenty-six (62%) women reported not having received contraceptive advice specific to CF and 24 (57%) said that they had not been warned about the potential interaction between broad-spectrum antibiotics and the combined pill.

DISCUSSION

Women with CF have a relatively high rate of unplanned pregnancy and do not receive optimal advice or use the full range of contraceptive methods. CF teams lack training in contraception and contraceptive services may not have a detailed knowledge of CF and its complications. New strategies are needed to focus the knowledge and skills of both teams in providing better services for women with CF.

Vitamin d deficiency in cystic fibrosis

Cystic Fibrosis is the most common inherited genetic respiratory disorder in the Western World. Hypovitaminosis D is almost universal in CF patients, likely due to a combination of inadequate absorption, impaired metabolism, and lack of sun exposure. Inadequate levels are associated with the high prevalence of bone disease or osteoporosis in CF patients, which is associated with increased morbidity including fractures, kyphosis, and worsening pulmonary status. Treatment goals include regular monitoring 25 hydroxyvitamin D (25OHD) levels with aggressive treatment for those with levels <75 nmol/L (<30 ng/mL). More research is needed to determine optimal supplementation goals and strategies.

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.

Intravenous zoledronate improves bone density in adults with cystic fibrosis (CF)

OBJECTIVE

Reduced bone mineral density (BMD) and increased rates of atraumatic fracture are observed in cystic fibrosis (CF) patients, causing increasing morbidity as this population ages. The study aimed to assess the safety, tolerability and effect on BMD of intravenous zoledronate in adults with CF and osteopaenia.

DESIGN

Randomized, double-blind, placebo-controlled clinical trial.

SETTING

Adult CF outpatient clinics at two hospitals.

PATIENTS

Twenty-two non-transplanted CF patients aged > or = 18 years with a bone densitometry T-score of < -1.5 at one of three sites (lumbar spine, femoral neck, distal forearm) were studied. Participants were randomized to receive either 2 mg zoledronate i.v. (n = 10) or normal saline (placebo, n = 12) every 3 months for 2 years (8 infusions). All participants received calcium and vitamin D supplements twice daily.

MEASUREMENTS

Percentage change in areal BMD from baseline.

RESULTS

Lumbar spine BMD increased from baseline more with zoledronate than placebo at 6 months (5.35 +/- 0.76 vs. 1.19 +/- 1.20%, P = 0.012), 12 months (6.6 +/- 1.5 vs. 0.35 +/- 1.55%, P = 0.011) and 24 months (6.14 +/- 1.86 vs. 0.44 +/- 0.10, P = 0.021). Femoral neck BMD increased more after zoledronate than placebo at 6 months (3.2 +/- 1.6 vs.-1.43 +/- 0.43%, P = 0.019), 12 months (4.12 +/- 1.8 vs.-1.59 +/- 1.4%, P = 0.024) and 24 months (4.23 +/- 1.3 vs.-2.5 +/- 1.41%, P = 0.0028). Forearm BMD did not change. Zoledronate was associated with flu-like and musculoskeletal side effects, particularly after the first infusion. There were no fractures in either group.

CONCLUSION

Intravenous zoledronate was significantly more effective than placebo for increasing BMD in adults with CF and osteopaenia, but side effects limited its tolerability.

The impact of incident fractures on health-related quality of life: 5 years of data from the Canadian Multicentre Osteoporosis Study

Using prospective data from the Canadian Multicentre Osteoporosis Study (CaMos), we compared health utilities index (HUI) scores after 5 years of follow-up among participants (50 years and older) with and without incident clinical fractures. Incident fractures had a negative impact on HUI scores over time.

INTRODUCTION

This study examined change in health-related quality of life (HRQL) in those with and without incident clinical fractures as measured by the HUI.

METHODS

The study cohort was 4,820 women and 1,783 men (50 years and older) from the CaMos. The HUI was administered at baseline and year 5. Participants were sub-divided into incident fracture groups (hip, rib, spine, forearm, pelvis, other) and were compared with those without these fractures. The effects of both time and fracture type on HUI scores were examined in multivariable regression analyses.

RESULTS

Men and women with hip fractures, compared to those without, had lower HUI measures that ranged from -0.05 to -0.25. Both women and men with spine fractures had significant deficits on the pain attributes (-0.07 to -0.12). In women, self-care (-0.06), mobility and ambulation (-0.05) were also negatively impacted. Women with rib fractures had deficits similar to women with spine fractures, and these effects persisted over time. In men, rib fractures did not significantly affect HUI scores. Pelvic and forearm fractures did not substantially influence HUI scores.

CONCLUSION

The HUI was a sensitive measure of HRQL change over time. These results will inform economic analyses evaluating osteoporosis therapies.

Longitudinal analysis of vertebral fracture and BMD in a Canadian cohort of adult cystic fibrosis patients

BACKGROUND

Vertebral fractures in patients with cystic fibrosis (CF) may contribute to an accelerated decline in lung function and can be a contraindication to lung transplantation. In this study, we examined longitudinal change in bone mineral density (BMD) and the prevalence of vertebral fractures in adult CF patients, without lung-transplant, attending a Canadian specialty clinic.

METHODS

Retrospective chart review of all patients attending an Adult Cystic Fibrosis Clinic at Hamilton Health Sciences in Hamilton, Canada. Forty-nine of 56 adults met inclusion criteria. Chest radiographs were graded by consensus approach using Genant's semi-quantitative method to identify and grade fractured vertebrae. Dual x-ray absorptiometry (DXA) scans were also reviewed.

RESULTS

The mean age of the cohort was 25.2 years (SD 9.4), 43% were male. The mean body mass index (BMI) was 19.8 (2.8) for males and 21.7 (5.1) for females. At baseline, the rate of at least one vertebral fracture was 16.3%; rising to 21.3% (prevalent and incident) after a 3-year follow-up. The mean BMD T-or Z-scores at baseline were -0.80 (SD 1.1) at the lumbar spine, -0.57 (SD 0.97) at the proximal femur, and -0.71 (SD 1.1) at the whole body. Over approximately 4-years, the mean percent change in BMD was -1.93% at the proximal femur and -0.73% at the lumbar spine.

CONCLUSION

Approximately one in five CF patients demonstrated at least one or more vertebral fractures. Moderate declines in BMD were observed. Given the high rate of vertebral fractures noted in this cohort of adult CF patients, and the negative impact they have on compromised lung functioning, regular screening for vertebral fractures should be considered on routine chest radiographs.

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.

Prevalence of osteoporosis in community-dwelling individuals with intellectual and/or developmental disabilities

OBJECTIVE

Measure central bone mineral density (BMD) in community-dwelling individuals with intellectual and/or developmental disabilities.

DESIGN

A cross-sectional study.

SETTING

A regional center providing outpatient medical, residential, and day activity services for individuals with intellectual and/or developmental disabilities.

PARTICIPANTS

Documented BMD results were obtained for 298 community-dwelling individuals with intellectual and/or developmental disabilities.

MEASUREMENTS

BMD by central dual-energy x-ray absorptiometry (DXA) on the participant's spine, converted into T-scores categories using CDC guidelines (T < or = -2.5 [osteoporotic]; -2.5 > T < -1.0 [osteopenic]; > or = -1.0 [normal]). Comparisons were made using multiple regression to determine significant independent risk factors for low BMD.

RESULTS

Significant predictors were noted in the rates of osteoporosis attributable to subject age, race, and level of ambulation. No gender differences were noted for the rate of osteoporosis in this community sample of individuals with intellectual and/or developmental disabilities, nor were any differences noted for varying levels of mental retardation. Diagnostic differences were significant only for those individuals with a diagnosis of metabolic error, who had a significantly lower rate of osteoporosis than the rest of the study population.

CONCLUSION

This study's findings regarding age, race, and level of ambulation are consistent with those of previous studies using an intellectually and/or developmentally disabled population as well as the general population at large. Our finding that the rate of osteoporosis among disabled males is higher than for males in the general population suggests a possible case-finding deficit for asymptomatic males in the general population. It is also interesting that the only diagnostic category observed to be statistically different from the group in general was metabolic error, a finding that warrants further investigation.

Pediatric dual-energy X-ray absorptiometry: technique, interpretation, and clinical applications

This article reviews the dual-energy x-ray absorptiometry (DXA) technique, its interpretation, and clinical applications with emphasis on the considerations unique to pediatrics. Specifically, the use of DXA in children requires the radiologist to be a "clinical pathologist," monitoring the technical aspects of the DXA acquisition, a "statistician" knowledgeable in the concepts of Z-scores and least significant changes, and a "bone specialist," aware of the DXA findings in a large number of clinical diseases, providing the referring clinician with a meaningful context for the numeric result obtained with DXA.

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.

Cystic fibrosis: a review of epidemiology and pathobiology

Improvements in outcomes for patients who have cystic fibrosis (CF) have been striking in the last 30 years. Median survival now approaches the fifth decade of life. Advances in the understanding of the basic defect and the pathobiology of CF have led to new treatments, some of which have undoubtedly contributed to this success. Improved understanding of the basic defect and the acquisition and maintenance of epidemiologic resources for the CF population in the United States have allowed us to determine predictors of survival and identify genetic, environmental, and therapeutic factors that may influence it. This article reviews some of the key epidemiologic and pathobiologic factors discovered thus far.

Pediatric DXA: clinical applications

Normal bone mineral accrual requires adequate dietary intake of calcium, vitamin D and other nutrients; hepatic and renal activation of vitamin D; normal hormone levels (thyroid, parathyroid, reproductive and growth hormones); and neuromuscular functioning with sufficient stress upon the skeleton to induce bone deposition. The presence of genetic or acquired diseases and the therapies that are used to treat them can also impact bone health. Since the introduction of clinical DXA in pediatrics in the early 1990s, there has been considerable investigation into the causes of low bone mineral density (BMD) in children. Pediatricians have also become aware of the role adequate bone mass accrual in childhood has in preventing osteoporotic fractures in late adulthood. Additionally, the availability of medications to improve BMD has increased with the development of bisphosphonates. These factors have led to the increased utilization of DXA in pediatrics. This review summarizes much of the previous research regarding BMD in children and is meant to assist radiologists and clinicians with DXA utilization and interpretation.

Controlled longitudinal study of bone mass accrual in children and adolescents with cystic fibrosis

BACKGROUND

A study was undertaken to observe the gains in bone mass in children and adolescents with cystic fibrosis (CF) over 24 months and to examine the relationship between areal bone mineral density (aBMD) and associated clinical parameters including physical activity, nutrition, and 25-hydroxyvitamin D (25OHD).

METHODS

Areal BMD of the total body (TB), lumbar spine (LS), and total femoral neck (FNt) were repeatedly measured in 85 subjects aged 5-18 years with CF and 100 age and sex matched controls over 2 years. At each visit anthropometric variables, nutritional parameters, pubertal status, disease severity, physical activity, dietary calcium, caloric intake, and serum 25OHD were assessed and related to aBMD.

RESULTS

After adjusting for age, sex, and height Z-score, gains in LS aBMD in children (5-10 years) and TB and FNt aBMD in adolescents (11-18 years) with CF were significantly less than in controls. Lean tissue mass was significantly associated with TB and LS aBMD gains in children and adolescents and explained a significant proportion of the aBMD deficit observed. Lung function parameters were significantly associated with aBMD gains in adolescents with CF.

CONCLUSIONS

Inadequate bone mass accrual during childhood and adolescence contributes to the low bone mass observed in adults with CF. Accounting for the height discrepancy which is frequently observed in those with CF, in addition to age and sex, is important when assessing low bone mass in children and adolescents with CF. To optimise an individual's potential to acquire maximal bone mass, it is necessary to maximise nutritional status and limit the progression of chronic suppurative lung disease.

Efectividad en la aplicación de tres protocolos de prevención y tratamiento de la osteoporosis en pacientes adultos con fibrosis quística

BACKGROUND AND OBJECTIVE

Reduction of bone mineral density (BMD) is a complication of cystic fibrosis (CF) which is observed in parallel to the increment of life expectancy in these patients. The aim of this study was to analyze the evolution of BMD following the application of a protocol for the prevention and treatment of osteoporosis.

PATIENTS AND METHOD

We performed a multidisciplinary prospective study in 21 adult patients with CF with a mean age of 24.3 (r: 19-44) years. We evaluated BMD results depending on the treatment schedule, and the annual relative change of BMD percentage was correlated with changes observed in respiratory function, corporal mass index (CMI), Brasfield radiologic score and Shwachman clinical score for a 3 years follow up period. Three regimens of treatment were applied: general measurements, supplementation of calcium and vitamin D, and 10 daily mg of alendronate plus calcium and vitamin D supplements.

RESULTS

Basal assessment showed that 14.2% of CF patients had a marked diminution of bone mass with respect to an age and sex matched control population, with a Z score of < -2 DE in lumbar vertebral and/or total femur. Another 38% showed a lessening of Z score between -1 and -2.5 DE. We observed a progressive annual reduction of BMD in all the anatomic areas analyzed: -0.52% (1.87) in lumbar spine, -1.17% (1.91) in total femur and -2.16% (2.65) in neck femur. The hip BMD annual decrement was related to that observed in FEV1. Only patients treated with alendronate did not suffer progressive BMD lose. Treatment with a combination of calcium, vitamin D and alendronate was more efficient in hip BMD than calcium plus vitamin D alone (p < 0.05). Also, this combination was better than no treatment at hip and femoral neck levels (p < 0.05).

CONCLUSIONS

Our work confirms that Spanish young adults patients with CF show low control matched BMD, and that it even worsens at follow-up. This decrement is not adequately halted with preventive treatment with supplements of calcium and vitamin D, and only patients treated with alendronate show increments of their BMD.

Musculoskeletal and neuromuscular interventions: a physical approach to cystic fibrosis

Children with CF are living longer than ever before, and thus issues pertaining to quality of life rather than just longevity of life need to be addressed by the entire healthcare team. This article addressed the issues pertaining to the external support of the dysfunctional internal organs: the secondary musculoskeletal (postural) and neuromuscular control deficits that occur to the maturing child with CF. The research pointed towards starting PT interventions for these deficits during the pre-pubescent phase when postural deficits were just emerging, but a suggestion was also made to explore whether these deficits can be even more effectively monitored and treated at an earlier age. The dual relationship between the muscles used to meet the increased respiratory demands of CF and the normal postural demands of physical activities was described through a model based on a soda-pop can and pressure support. A pre-pubescent child with a typical progression of CF was presented as a case report to illustrate how a PT programme that was focused on postural deficits could be implemented and what type of outcomes might be possible. The child made significant changes within a relatively short time frame of 4 months, proposing that the musculoskeletal and neuromuscular systems may play a significant role in the medical and physical long-term outcomes of CF. For that reason, the physical as well as medical needs of the patient should be incorporated into a comprehensive multi-system approach to the disease across the lifespan.

Efficacité des biphosphonates oraux sur la déminéralisation osseuse des patients atteints de mucoviscidose

Disturbances in bone mineralization are frequent in cystic fibrosis but few studies have focused on the use of biphosphonates in this indication, and none on the use of oral etidronate. We report our experience using this latter treatment.

METHODS

The study was retrospective and included five children and three adults with cystic fibrosis (six males and two females) aged seven to 30 years with Z-scores for lumbar bone density lower than -2 SD after one year of calcium (1 g/day) and vitamin D (900 UI/day and 300,000 UI/6 months) supplementation. All were treated during one year with etidronate: four courses of 15 days (one course per trimester) with doses ranging from 4 to 8 mg/kg per day. Calcium and vitamin D supplementation was continued between the etidronate treatment course. Total body and lumbar bone mineral density (BMD) were measured three times: at the beginning and the end of the year of calcium and vitamin D supplementation and at the end of the year of supplementation plus the four courses of etidronate treatment.

RESULTS

The increase in BMD in absolute value (g/cm2) and in Z-score was significantly higher (P <0.05) after the year of combined supplementation and etidronate treatment (total body g/cm2: 3+/-1%, Z-score: 2+/-1% and lumbar spine g/cm2: 6+/-5%, Z-score: 3+/-4%) than after supplementation alone (total body g/cm2: -1+/-3%, Z-score: -4+/-3% and lumbar spine g/cm2: -1+/-3%, Z-score: -4+/-4%). Supplementation alone improved the total BMD in only one patient and the lumbar BMD in three, whereas after etidronate treatment the total and lumbar BMD were improved in the eight patients. None of the patients presented with side effects that could be attributed to the treatment.

CONCLUSION

Oral etidronate treatment is well-tolerated and capable of improving bone mineralization in patients with cystic fibrosis. Further work will be necessary to determine the optimal dosage and the optimal frequency for the treatment series.

Randomised double blind placebo controlled trial investigating the effect of calcium and vitamin D supplementation on bone mineral density and bone metabolism in adult patients with cystic fibrosis

BACKGROUND

Low bone mineral density (BMD) is prevalent in adults with cystic fibrosis and might be related to calcium and vitamin D malabsorption from the gastrointestinal tract. The aim of this study was to investigate the effect of calcium and vitamin D supplementation on BMD and bone metabolism in these subjects.

METHODS

Patients were invited to participate if they had a BMD Z score of -1 or less in the lumbar spine, proximal femur or distal forearm. Patients were randomised to receive calcium 1 g+vitamin D 800 IU or placebo daily, in addition to their regular vitamin D supplements (900 IU/day). BMD and bone biochemical markers were measured before and after 1 year of treatment.

RESULTS

After 12 months, the treatment group (n=15) showed a reduced rate of bone loss compared with the control group (n=15) in the lumbar spine (mean difference 1.9% [CI -0.9% to 4.6%]), total hip (mean difference 0.7% [CI -2.2% to 3.5%]) and distal forearm (mean difference 1.7% [CI -2.2% to 5.5%]), but these changes did not reach statistical significance. There was also a trend towards a reduction in bone turnover in the treatment group.

CONCLUSIONS

Calcium and vitamin D supplementation reduced the rate of bone turnover and bone loss in adult patients with cystic fibrosis, but these changes did not reach statistical significance. These data suggest that a longer term trial of this simple intervention would be justified.

Treatment of bone disease in cystic fibrosis

PURPOSE OF REVIEW

As individuals with cystic fibrosis (CF) have experienced marked improvements in longevity over the last three decades, bone disease has emerged as a new problem. Bone disease in CF has not been previously reviewed in this journal. Therefore, this review will give a brief overview of bone disease in CF and then concentrate on treatment options.

RECENT FINDINGS

In some series, as many as three fourths of adults with CF have low bone density. Decreased absorption of fat-soluble vitamins due to pancreatic insufficiency, altered sex hormone production, chronic inflammation, physical inactivity, and glucocorticoid treatment are some of the factors that contribute to this problem. Vitamin D depletion most likely contributes to bone disease, but identifying the safest and most efficacious vitamin D supplementation has yet to be resolved. Calcium and vitamin K supplementations are important if the diet contains less than the recommended amounts. Treatment of delayed puberty and adult hypogonadism with hormone replacement is recommended to achieve peak bone mass and maintain bone density. Bisphosphonates, including pamidronate and alendronate, are beneficial in improving bone mineral density before and after transplantation in CF adults. Bisphosphonates have not been studied in CF children.

SUMMARY

Although much progress has been made in our understanding of the pathogenesis, natural history, and clinical manifestations of bone disease in CF, treatment options are still evolving. More attention to nutrition, in terms of the maintenance of lean body mass and vitamin D and calcium supplementation, is likely to decrease bone complications. Bisphosphonates can be of value in CF adults with low bone density. Several clinical trials are under way to help optimize the treatment of CF bone disease.

Prevalence and correlates of vertebral fractures in adults with cystic fibrosis

INTRODUCTION

Osteoporosis associated with cystic fibrosis (CF) is becoming increasingly important as the life expectancy of patients continues to increase.

MATERIALS AND METHODS

We studied 191 adults with CF (18-50 years old; 100 men, 91 women). Total body, lumbar spine, and total proximal femur bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry, and lateral spinal radiographs were taken for assessment of vertebral fractures. A range of anthropometric, clinical and biochemical variables were evaluated as potential correlates.

RESULTS

BMD T score values at the lumbar spine lower than -2.5 SD were observed in 27.3% and 11.2% of male and female patients, respectively. These proportions fell to 14% and 9.9% for total hip and 10.4% and 12.1% for total body, in men and women, respectively. Vertebral deformities were identified in 26.7% of the patients with a slightly higher prevalence in males (32%) than in females (21%, P = 0.058). Multiple vertebral deformities were observed in 12% and 7.7% of men and women, respectively. BMD values were significantly related to body weight, FEV1, age of puberty and occasionally to cumulative steroid dose in both genders. BMD values were also significantly related with serum albumin, IgG and cholinesterase. Serum estradiol levels were found below the normal range in 23% of the women and 27% of the men, and was significantly related to femur BMD values in both women and men. Significantly lower serum estradiol and free testosterone levels were observed in men with vertebral fractures. Serum osteocalcin was below the normal range in 36% and urinary deoxypyridinoline above the normal range in 51% of the patients.

CONCLUSIONS

This study indicates that osteoporosis is a common complication of CF, being related to disease progression and apparently due to both excess bone resorption and inadequate bone formation. Estradiol deficiency may have a significant role in the pathogenesis in both genders. Vertebral fracture prevalence is high and greater than expected from prevalent BMD values.

Effect of oral bisphosphonates on bone mineral density and body composition in adult patients with cystic fibrosis: a pilot study

BACKGROUND

Approximately two thirds of adult patients with cystic fibrosis have reduced bone mineral density and up to one quarter have osteoporosis at one or more sites. Any bone mineral deficits are likely to be exacerbated in patients following lung transplantation by their immunosuppressive regimen. Vertebral collapse and rib fractures will impair the ability to cough and the efficacy of physiotherapy treatments.

METHODS

Patients attending the Leeds Regional Adult Cystic Fibrosis Unit with either osteopenia or osteoporosis on dual energy x ray absorptiometry (DXA) scanning were offered treatment with oral bisphosphonates after exclusion of abnormal vitamin D, calcium, or phosphate levels, abnormal thyroid function, or hypogonadism. Those declining treatment or patients with a normal initial DXA scan formed the control group. A second DXA scan was performed after a mean of 2.4 years in the treatment group and 2.9 years in the non-treatment group. Patients in the active group were asked to complete a short questionnaire detailing their adherence to treatment.

RESULTS

The medians of the differences in annual changes in bone parameters between treatment and control groups showed significant differences in bone mineralisation in favour of the treatment group at the lumbar spine (L2-L4), the femoral neck, and for total body measurements. There were no significant differences in weight, height, or body composition in either patient group. Most treated patients stated that they adhered to treatment most of the time.

CONCLUSION

Treatment with oral bisphosphonates may improve bone mineralisation in adult patients with cystic fibrosis. The results of this pilot study need to be further explored in a randomised controlled trial.

Normal annual increase of bone mineral density during two years in patients with cystic fibrosis

OBJECTIVES

To determine prospectively for 2 years the change in bone mineral density (BMD) in patients with cystic fibrosis (CF) and to correlate clinical data and routine biochemical parameters of bone metabolism and infection with BMD.

METHODS

Fifty-four patients with CF, aged 6 to 33 years, were included. BMD was measured using dual-energy x-ray absorptiometry in lumbar spine (LS) and femoral neck (FN). Anthropometric data and biochemical markers of bone metabolism and infection were measured. The number of intravenous antibiotic courses per year (ivAC) and pulmonary function were assessed.

RESULTS

The patients had normal anthropometric data and normal growth, but 36% and 33% of the patients had BMD z score <-1 standard deviation in LS and in FN, respectively. Nevertheless, BMD increased at a normal rate during the 2 years and was correlated to weight and lung function. Intact parathyroid hormone was positively correlated with the increase of BMD in both LS and FN during childhood. Blood sedimentation rate, serum concentration of immunoglobulin G, and ivAC were negatively correlated with BMD in FN. Patients with 2 more severe CF transmembrane conductance regulator mutations had significantly lower BMD in FN than other genetic combinations.

CONCLUSION

The study suggests that low BMD in CF is multifactorial and depends on infection and nutritional parameters. Differences in BMD of LS and FN suggested higher susceptibility to infection in FN at all ages. Longitudinal studies starting early before bacterial colonization would be valuable to determine the relative role of infection in the development of BMD in CF.

Inflammatory related changes in bone mineral content in adults with cystic fibrosis

BACKGROUND

Proinflammatory cytokines stimulate osteoclast activity and this could lead to increased bone resorption in patients with cystic fibrosis. The aim of this study was to determine whether markers of systemic inflammation are related to changes in bone mineral content (BMC) in adults with cystic fibrosis.

METHODS

Total body BMC was assessed by dual energy x ray absorptiometry in 100 patients (54 male) of mean (SD) age 25.6 (7.1) years and forced expiratory volume in 1 second (FEV(1)) 61.8 (24.1)% predicted on recruitment to the study and 1 year later. Blood was also taken at these time points to measure markers of systemic inflammation.

RESULTS

After 1 year BMC had reduced by 16.1 (62.1) g, p = 0.01; (0.6 (2.8)%). The change in BMC was related to mean levels of interleukin (IL)-6 (r(s) = -0.39, p<0.001) and C reactive protein (r(s) = -0.34, p = 0.002), intravenous antibiotic use (r(s) = -0.27, p = 0.006) and oral corticosteroid use (r(s) = -0.20, p = 0.045). Urinary markers of osteoclast activity were also related to IL-6 (r(s) = 0.27, p = 0.02). Multiple linear regression revealed that IL-6 (coefficient -2.2 (95% CI -3.4 to -1.0) per pg/ml, p = 0.001), colonisation with Burkholderia cepacia (coefficient -46.8 (95% CI -75.5 to -18.1), p = 0.002), and annual change in BMI (coefficient 15.4 (95% CI 3.6 to 27.2) per kg/m(2), p = 0.011) were independently significant predictors of annual change in BMC.

CONCLUSIONS

These data suggest a pathophysiological mechanism by which chronic pulmonary infection results in bone loss in patients with cystic fibrosis.

Bone mineral density and bone acquisition in children and young adults with cystic fibrosis: a follow-up study

OBJECTIVE

To investigate bone mineral density and bone homeostasis in cystic fibrosis (CF) and to assess changes in a 2-year period.

METHODS

Thirty-eight patients with clinically stable CF (11 children, 16 adolescents, 11 young adults) were enrolled. No patient was treated with corticosteroids before or during the study. Weight and height Z scores and bone mineral density (BMD) Z-score at the femoral neck and the lumbar spine were recorded at the beginning of the study and after 2 years. Osteocalcin and cross-link excretion, both measurements of bone turnover were also measured. Correlations between BMD, bone turnover parameters, disease severity, pubertal stage, and nutritional state were calculated. The maternal BMD was also determined and related to that of the child.

RESULTS

Height and weight Z scores were normal in children and below normal in adolescents. Puberty was delayed in most patients. Bone age was lower than chronological age in adolescents. Lumbar spine and femoral neck BMD Z scores were below normal in each age group. Disease severity determined by Schwachman score correlated with lumbar BMD (r = 0.45, P < 0.02). BMD Z scores did not change during 2 year follow-up. Maternal and patient lumbar and femoral BMD correlated significantly (r = 0.51, P < 0.01, and r = 0.54, P < 0.01, respectively).

CONCLUSIONS

Bone deficit is present in patients with CF who have never received steroid treatment. Delay of puberty, chronic inflammation, or genetic susceptibility might be responsible for this phenomenon which was found in patients who had never received steroids and who were in relatively good clinical state.

Bone mineral density in Australian children, adolescents and adults with cystic fibrosis: a controlled cross sectional study

BACKGROUND

Low bone mineral density (BMD) is recognised in individuals with cystic fibrosis (CF) although the pathogenesis remains unclear. The aims of this study were to compare BMD over a broad continuum of Australian individuals with CF with healthy controls and to examine the relationship between BMD and clinical parameters including physical activity, nutrition, and vitamin D levels.

METHODS

BMD of the lumbar spine (LS), total body (TB), femoral neck (FN), cortical wrist (R33%), and distal wrist (RUD) was examined in 153 individuals with CF aged 5.3-55.8 years (84 males) and in 149 local controls aged 5.6-48.3 years (66 males) using dual energy x ray absorptiometry. Anthropometric variables, body cell mass, markers of disease severity, corticosteroid usage, measures of physical activity, dietary calcium and caloric intake and serum vitamin D were assessed and related to BMD.

RESULTS

Compared with controls, mean BMD was not significantly different in children aged 5-10 years with CF. Adolescents (females 11-18 years, males 11-20 years) had reduced TB and R33% BMD when adjusted for age, sex, and height (difference in BMD (g/cm2) adjusted means between control and CF: TB=0.04 (95% CI 0.01 to 0.07); R33%=0.03 (95% CI 0.01 to 0.06)). BMD was reduced at all sites except R33% in adults (difference in BMD (g/cm2) adjusted means between control and CF: TB=0.05 (95% CI 0.02 to 0.09); LS=0.08 (95% CI 0.03 to 0.14); FN=0.09 (95% CI 0.03 to 0.15); RUD=0.03 (95% CI 0.01 to 0.05)). In children/adolescents BMD was weakly associated with nutritional status and disease severity.

CONCLUSIONS

BMD was normal in a well nourished group of prepubertal children with CF. A BMD deficit appears to evolve during adolescence and becomes more marked in adults. Individuals with CF should optimise nutrition, partake in physical activity, and maximise lung health in order to optimise BMD. Further longitudinal studies are required to understand the evolution of reduced BMD in young people and adults with CF.

Efficacy of Alendronate in Adults with Cystic Fibrosis with Low Bone Density

As adults with cystic fibrosis (CF) have enjoyed incremental increases in longevity over the last few decades, they have also been suffering from low bone density and its clinical manifestations, fractures and kyphosis. We conducted a placebo-controlled, randomized, double-blinded trial of alendronate (10 mg/day orally) (n = 24) compared with placebo (n = 24) for 1 year in 48 patients to improve bone mineral density at the spine as the primary endpoint. All patients received 800 IU of cholecalciferol and 1,000 mg of calcium carbonate. Both groups were similar in age, sex, CF mutations, bone density T scores, renal function, and body mass index at study onset. The alendronate-treated patients gained (mean +/- SD) 4.9 +/- 3.0% and 2.8 +/- 3.2% bone density after 1 year versus placebo, which lost (mean +/- SD) 1.8 +/- 4.0% and 0.7 +/- 4.7%, in spine and femur bone density, respectively (p < or = 0.001 for the spine; p = 0.003 for the femur). Urine N-telopeptide, a bone resorption marker, levels declined in the treatment group more than in the control group (p = 0.002), consistent with the known antiresorptive effects of bisphosphonates. Alendronate was more effective than placebo in improving spine and femur bone mineral density and is a promising agent for the long-term prevention and management of bone disease in patients with CF.

Management of Osteoporosis in Adults with Cystic Fibrosis

Cystic fibrosis (CF) is the most common genetic disease that causes respiratory failure within the Caucasian population. The life span of patients with CF has gradually increased from a median of 2 years of age to >30 years. Concurrent with this increased lifespan, a variety of other nutritional, endocrine and bone issues have been recognised. Decreased absorption of fat-soluble vitamins (D and K in particular) because of pancreatic insufficiency, altered sex hormone production, chronic inflammation, a lack of physical activity, glucocorticoid treatment and an intrinsic hyper-resorptive bone physiology are some of the factors that contribute to the prominence of bone disease within the CF population. In some series, three-quarters of adult patients with CF have osteopenia or osteoporosis. Lung transplantation is one viable treatment for patients with end-stage CF, which requires a lifetime of antirejection medication. Immunosuppressant therapies have a detrimental effect on bone mineral density (BMD). To combat the multifactorial nature of CF-related bone disease, advances in nutritional and vitamin supplementation, and anti-resorptive and anabolic therapies have evolved. Chronic vitamin D depletion contributes to bone disease in the CF population. The isoform of vitamin D that is the best and safest supplement, with the lowest cost, has yet to be identified. However, it is clear that many patients with CF who receive the standard of care (i.e. two daily combination vitamin A, D, E and K tablets [ADEKs]) may still be vitamin D-deficient. More aggressive supplementation needs to be individualised, with close monitoring of serum 25-hydroxyvitamin D levels. Similarly, routine calcium supplementation may be important, and evidence is accumulating that vitamin K also plays an important role in maximising and maintaining BMD. Early recognition and treatment of delayed puberty in adolescents and hypogonadism in adults with hormone replacement therapy is recommended to maintain BMD in patients with CF. Bisphosphonates, including pamidronic acid, etidronic acid and alendronic acid, reduce bone resorption by inhibiting the recruitment and function of osteoclasts. Pamidronic acid is beneficial in improving BMD in CF patients before and after transplantation. Bisphosphonate therapy and minimisation of glucocorticoid dosage have been shown to be efficacious in glucocorticoid-induced osteoporosis. Teriparatide is the first US FDA-approved anabolic growth agent for bone, and has been shown to increase BMD and decrease fracture incidence in postmenopausal women. Teriparatide may offer a new avenue for treating bone disease in CF since many patients may have poor bone formation as well as accelerated bone breakdown. Numerous clinical trials are underway to optimise treatment of CF osteoporosis.

Osteoporosis in Canadian adult cystic fibrosis patients: a descriptive study

BACKGROUND

Cystic fibrosis is the most common fatal autosomal recessive genetic disease in the Caucasian population. Osteoporosis is increasingly being recognised as an important complication in people with cystic fibrosis.

METHODS

A descriptive study of adult cystic fibrosis patients receiving care at a Canadian tertiary care hospital was conducted to evaluate the prevalence of osteoporosis, the prevalence of non-vertebral fractures, and the change in bone mineral density during the course of a year. Data on bone mineral density were obtained for 40 adult cystic fibrosis patients by reviewing dual x-ray absorptiometry scans taken at baseline (when annual scans became standard clinical practice) and one year prior to baseline. Data on prevalent fractures were obtained by reviewing all available patient charts. Clinical and laboratory data were collected from an existing clinic database.

RESULTS

Over half of the 40 patients had reduced T- and Z-scores at baseline. For the 27 patients who had data available one year prior to baseline, total hip and lumbar spine bone mineral density had decreased by 3.04% and 0.86% after one year while total body bone mineral density had not changed significantly. Four prior non-vertebral fractures were reported in three patients (1,146 patient-years).

CONCLUSION

This study confirms that osteoporosis is a significant problem in adult cystic fibrosis patients, and constitutes the first published evidence of cystic fibrosis bone disease in Canadians.