Nutritional status of an adult cystic fibrosis population

Dietary intake and quality among adults with cystic fibrosis: A systematic review

AIMS

This systematic review aims to describe the dietary quality, dietary intake and related behaviours of adults diagnosed with cystic fibrosis.

METHODS

A comprehensive literature search was conducted in four databases (Medline, CINAHL, EMBASE, CENTRAL); studies were included if they addressed dietary intake, diet quality or eating behaviours among adults (≥15 years) living with cystic fibrosis and were published from January 2000 to November 2022. The Mixed Methods Appraisal Tool was used to assess the risk of bias and quality of included studies. Findings were synthesised narratively.

RESULTS

Nineteen observational studies (n = 2236) were included and considered high to moderate quality. Most (13/19) studies reported that individuals with cystic fibrosis were consuming high-energy diets; where studies reported energy intake as a proportion of requirements met, energy intake was high, even when using individualised or cystic fibrosis-specific referents. In addition, fat intakes as a proportion of energy appeared high (29%-39% of total energy), particularly as current guidelines recommend macronutrient profile similar to the general population (<30% of total energy). There was considerable variation in the reporting of fatty acid profiles and other nutrients. Five studies reported on concerns regarding diet and eating in this population.

CONCLUSION

Findings from the current review suggest dietary intakes of adults with cystic fibrosis appear to be less than optimal and concerns about diet, weight and food may be emerging in this population. Future research utilising consistent measures of dietary assessment and reporting, reporting of medical therapies, and exploring potential concerns about diet and eating is warranted.

What do people with cystic fibrosis eat? Diet quality, macronutrient and micronutrient intakes (compared to recommended guidelines) in adults with cystic fibrosis-A systematic review

BACKGROUND

Treatment advancements have improved life expectancy and nutritional status of people with cystic fibrosis (CF). Alongside reductions in malnutrition, incidences of overweight, obesity and risk factors for diet-related chronic diseases have increased in recent years. This study aimed to synthesise the available literature on diet quality, macronutrient and micronutrient intakes compared to the recommended guidelines in adults with CF, an essential step in deducing the optimal dietary pattern and intakes for CF adults.

METHODS

A systematic search of five electronic databases from inception until April 2023 was conducted using keywords related to CF, diet quality and nutrient intakes.

RESULTS

Twenty-one studies were included comprising 18 cross-sectional, one cohort and two case control studies, reporting data from 724 adults with CF. Energy and / or macronutrient intake data was reported across 17 cohorts, eight studies provided micronutrients data, and diet quality was determined for four CF cohorts by using a diet quality score, and / or categorising food intake into servings per day for food groups and comparing findings to national dietary guidelines. Although energy intake recommendations were met, and most micronutrient requirements were achieved through supplementation, total energy intake from fat was above recommendations and diet quality was poor.

CONCLUSION

This is the first systematic review comprehensively evaluating literature on dietary intakes of adults with CF. Energy-dense, nutrient-poor foods contribute to intakes which pose risk in developing diet-related chronic diseases. Revision of dietary guidelines and practice change in CF nutritional therapy is warranted to optimise nutrition and health outcomes.

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.

Pseudomonas aeruginosa, the type of mutation, lung function, and nutritional status in adults with cystic fibrosis

OBJECTIVE

The aim of this study was to describe the relationship between the prevalence of Pseudomonas aeruginosa (PA) and lung function, as well as the nutritional status and type of gene mutation in adult patients with cystic fibrosis (CF).

METHODS

This cross-sectional study evaluated 103 Polish adults with CF the following: • The occurrence of PA and the level of bacterial susceptibility to antibiotics; • Type of mutation in the CFTR gene; • Nutritional status assessed by body mass index (BMI), and • Lung function measured by forced expiratory volume in 1 s (FEV1%).

RESULTS

The absence or presence of PA and the level of bacterial resistance were significantly related to the type of gene mutation (P < 0.001). In patients with a severe mutation, PA more often was extensively drug resistant or pandrug resistant compared with Pseudomonas culture-negative patients or patients with mild or unclassified mutations on both alleles. Associations were found between the presence of PA and lower values of BMI (P < 0.001), and FEV1% (P < 0.001). The risk for PA occurrence and the development of bacterial resistance increased twice in the case of severe mutation (odds ratio [OR], 2.51; 95% confidence interval [CI], 1.62-3.89), four times when BMI decreased <18.5 (OR, 4.15; 95% CI, 1.43-10.08). and six times when FEV1% fell <40 (OR, 6.75; 95% CI, 3.11-14.64).

CONCLUSIONS

The presence of PA is associated with lower FEV1% and BMI values. Deterioration of lung function, undernutrition, and severe type of gene mutation are linked to a higher probability of PA acquisition and resistance to antibiotic treatment.

Dietary intake in cystic fibrosis and its role in glucose metabolism

BACKGROUND

Dietary intervention in cystic fibrosis (CF) has historically focused on high-energy diets to address malnutrition, with little attention on diet quality. With increased survival, CF complications such as impaired glucose tolerance (IGT) and cystic fibrosis related diabetes (CFRD) have increased in prevalence. In the absence of consensus on the management of IGT, the role of dietary intake, specifically carbohydrate quality, requires consideration.

AIMS

The aims of this study were to: 1) determine nutritional quality of dietary intake at an adult CF clinic and compare this to the Australian Dietary Guidelines 2) explore relationships between dietary intake, including glycaemic index (GI) and glycaemic load (GL), and glucose response variables using continuous glucose monitoring (CGM).

METHODS

Adults attending a Sydney hospital were recruited to undergo CGM for five-seven days and record dietary intake using a food record over the CGM period. The relationship between variables of dietary intake, including GI and GL and variables of glycaemic response, including mean amplitude of glycaemic excursions (MAGE), percentage of time in hyperglycaemic and euglycaemic range, were determined.

RESULTS

Eighteen participants completed the study with 87 full days of dietary and CGM data. Dietary intake was higher than recommendations in the Australian Dietary Guidelines in relation to grains and protein foods and only slightly higher in saturated fat. Bivariate correlations showed dietary GI was significantly positively associated with percentage of time in hyperglycaemic range. Dietary GL was significantly associated with SD, MAGE and percentage of time in euglycaemic range on CGM. Results remained significant when controlled for energy intake in partial correlation analyses.

CONCLUSIONS

This study suggests GI and GL may be important dietary factors influencing glucose metabolism in CF. Further studies exploring low GI or GL diets as a dietary intervention in CF are the next step.

Nutritional assessment in adults with cystic fibrosis

OBJECTIVES

Clinical experience with patients with cystic fibrosis (CF) suggests a nutritional risk in this population. In addition to the lung pathology, a main pathophysiologic concern is the viscous mucus blocking pancreatic ducts, leading to reduced production of pancreatic enzymes. Therefore, maldigestion and consequently malabsorption (particularly fat and fat-soluble vitamins) occur, resulting in steatorrhea, vitamin deficiencies, and subsequently manifest malnutrition. The aim of this study was to investigate the nutritional status and determine the prevalence of malnutrition in an adult Swiss CF cohort.

METHODS

This was an observational cohort study in which the nutritional status and dietary habits of patients with CF and healthy controls were compared. Assessment was based on the nutritional risk screening (NRS-2002), dietary habits (7-d dietary record), body composition (bioelectrical impedance analysis), anthropometrics, resting energy expenditure (REE; indirect calorimetry), and physical or mental function (hand-grip strength, Short Form-36 v2).

RESULTS

Nineteen patients (15 men, mean age 32 y) and 15 controls (8 men, mean age 49 y) were included. Eight patients (42%) were at nutritional risk (NRS-2002 ≥3). Patients had higher energy intake/body weight (P = 0.021) with lower body fat percentage (P < .001), body mass index (P = 0.030), and physical/mental health scores (P < 0.001) than controls. Energy intake was higher than REE in patients (P = 0.003), but not in controls (P = 0.373).

CONCLUSIONS

Prevalence of malnutrition was high in this CF cohort, coinciding with low body fat percentage and low body mass index despite high energy and protein intake. Energy requirements of patients with CF should be estimated as approximately twice the Harris-Benedict REE and 1.7 times indirect calorimetry REE, while ensuring adequate intake of pancreatic enzymes.

Associations between Flavonoid Intakes and Gut Microbiota in a Group of Adults with Cystic Fibrosis

Dietary flavonoid intakes can influence gut microbiota (GM), which in turn can affect immune function and host metabolism, both vital considerations in cystic fibrosis (CF) management. In CF, GM may be altered and link to CF respiratory events. This study explored the relationship between flavonoid intakes and GM in free-living adults with CF. Associations between the overall GM variations (unweighted and weighted UniFrac distances between pyrosequencing results of bacterial 16-ss rDNA from frozen faecal samples of sixteen CF adults) and standardised dietary flavonoid intakes (a validated flavonoid-specific food frequency questionnaire) were analysed using adonis tests. Flavonoid intakes that were significant at a false discovery rate (FDR) < 0.3 were subjected to Spearman correlation tests with standardised bacterial relative abundances (FDR < 0.3). Gallocatechin intakes (p = 0.047, q = 0.285) were associated with unweighted UniFrac distances. Intakes of apigenin (p = 0.028, q = 0.227) and kaempferol (p = 0.029, q = 0.227), and % flavonoid intake as flavones (p = 0.013, q = 0.227) and flavonols (p = 0.016, q = 0.227) (both excluding contribution of tea) were associated with weighted UniFrac distances. Among these, gallocatechin correlated with the genus Actinomyces and family Actinomycetaceae (Actinobacteria). Gallocatechin correlated negatively with class Coriobacteriia (Actinobacteria). Intakes of some flavonoids may be associated with GM variations with potential consequences for metabolism, immune function, and inflammation, which are important in CF lung disease and co-morbidity management.

Evaluating the impact of 2006 Australasian Clinical Practice Guidelines for nutrition in children with cystic fibrosis in Australia

OBJECTIVES

To determine the association between the implementation of the 2006 Australasian Clinical Practice Guidelines for Nutrition in Cystic Fibrosis (CF) and the nutritional status of children participating in the Australian Cystic Fibrosis Data Registry (ACFDR).

METHODS

This research consisted of a quantitative study using ACFDR data and a survey of clinicians and dietitians treating children with CF. Two independent cohorts of children (2-5 years and 6-11 years) were selected from ACFDR between 1998 and 2014 (N = 2304). Generalised estimating equation model was used to assess weight, height and body mass index (BMI) z-scores for each patient before and after the implementation of the nutrition guidelines. A nationwide online survey was sent to 48 clinicians to explore the enablers and barriers to implementation of the guidelines.

RESULTS

Data analysis showed significant increase (p < 0.05) in mean weight, height and BMI z-scores ranging from 0.06 to 0.18 after implementation of the guidelines in both cohorts of children. Nineteen (39%) clinicians participated in the survey. The majority of the respondents adopted the recommendations into their practice and used the guidelines as part of their professional development. Structural barriers included a lack of adequate staff resources and clinic space for consultations, inappropriate staff classification, high staff turnover and lack of mentoring support.

CONCLUSION

In children participating in the ACFDR, nutritional status improved after the implementation of the 2006 guidelines. Survey results revealed enablers and barriers to guideline implementation and will inform implementation strategies for the revised Australasian nutrition guidelines for CF, released in 2017.

Dietary intake and nutritional status in a Scandinavian adult cystic fibrosis-population compared with recommendations

BACKGROUND

Malnutrition is a well-known complication in cystic fibrosis (CF). There is good evidence that maintaining a normal body-weight correlates well with improved survival in CF. Energy intake in excess of 120% of the estimated average requirement (EAR) has been advised since 1980s.

OBJECTIVES

To investigate the nutritional intake and status in the adult Scandinavian CF-population.

SUBJECTS/METHODS

A cross-sectional multi-centre study was used to investigate the nutritional status of 456 adult CF-patients (2003 2006). Height and weight were measured and body mass index (BMI) and z-scores were calculated. Pulmonary function was examined by dynamic spirometry. A 7-day pre-coded food record (FR) obtained energy and nutrient intake data in 180 patients.

RESULTS

The mean energy intake was 114 (SD 30.0)% of EAR and thus significantly lower than the target of 120% EAR (p< 0.001) for patients with pancreatic insufficiency (PI) (n=136). Mean BMI was 22.0 (SD 2.9), the prevalence of BMI <18 was 13% and the prevalence of BMI ≥25 was 15% (n=136). Mean BMI was 20.8 (SD 2.4) in PI-patients with FEV(1) <70% and 23.2% (SD 3.0), in PI-patients with FEV(1) ≥70%, mean difference 2.4, (95% CI: 1.5, 3.3) (p<0.001), but there was no difference in energy intake. BMI ≥18.5 and a reported energy intake <120% were revealed in 54% of the PI-patients.

CONCLUSIONS

The energy intake did not reach the recommended 120% EAR, but the prevalence of underweight was lower than reported in other studies. The recommendation may exceed the requirement for a number of CF-patients. The nutritional status must still be closely monitored and nutritional advice and intervention should be individualised and adjusted to actual needs.

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.

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.

Nutrient status of adults with cystic fibrosis

Nutrition is thought to influence disease status in patients with cystic fibrosis (CF). This cross-sectional study sought to evaluate nutrient intake and anthropometric data from 64 adult outpatients with cystic fibrosis. Nutrient intake from food and supplements was compared with the Dietary Reference Intakes for 16 nutrients and outcomes influenced by nutritional status. Attention was given to vitamin D and calcium given potential skeletal implications due to cystic fibrosis. Measurements included weight, height, body composition, pulmonary function, and serum metabolic parameters. Participants were interviewed about dietary intake, supplement use, pulmonary function, sunlight exposure, and pain. The participants' mean body mass index (+/-standard deviation) was 21.8+/-4.9 and pulmonary function tests were normal. Seventy-eight percent used pancreatic enzyme replacement for malabsorption. Vitamin D deficiency [25-hydroxyvitamin D (25OHD)<37.5 nmol/L] was common: 25 (39%) were deficient despite adequate vitamin D intake. Lipid profiles were normal in the majority, even though total and saturated fat consumption represented 33.0% and 16.8% of energy intake, respectively. Reported protein intake represented 16.9% of total energy intake (range 10%-25%). For several nutrients, including vitamin D and calcium, intake from food and supplements in many participants exceeded recommended Tolerable Upper Intake Levels. Among adults with cystic fibrosis, vitamin D deficiency was common despite reported adequate intake, and lipid profiles were normal despite a relatively high fat intake. Mean protein consumption was adequate, but the range of intake was concerning, as both inadequate or excessive intake may have deleterious skeletal effects. These findings call into question the applicability of established nutrient thresholds for patients with cystic fibrosis.

[Validity and reliability of the St George's Respiratory Questionnaire in adults with cystic fibrosis]

OBJECTIVE

To study self-perceived quality of life in adults with cystic fibrosis (CF), and to assess the validity of the St George's Respiratory Questionnaire (SGRQ) for use in these patients.

PATIENTS AND METHODS

We studied 37 adults with CF who were in stable condition as indicated by their respiratory and nutritional status. Disease severity was assessed by spirometry in conjunction with a modified National Institutes of Health (NIH) scoring system and the Bhalla scale. Nutritional status was evaluated by measuring height and weight, calculating body mass index, analyzing bioelectric impedance, and performing various laboratory tests. The patients' quality of life was assessed using the SGRQ.

RESULTS

SGRQ scores were higher (indicating poorer quality of life) among patients with CF than in the general population or among patients with chronic obstructive pulmonary disease. Internal consistency coefficients indicated the SGRQ had good reliability (Cronbach alpha 0.864). Women with CF tended to score higher than men, although this difference was not statistically significantly. A statistically significant relationship was observed between SGRQ score and severity of pulmonary impairment (the more severe the impairment, the worse the patient's quality of life). Statistically significant positive relationships were found between SGRQ domains and age, body mass index, and body fat percentage. Significant negative relationships were found between these domains and the modified NIH score, the Bhalla score, forced expiratory volume in 1 second (expressed as a percentage of predicted), and somatomedin C and zinc levels.

CONCLUSIONS

Self-perceived quality of life is worse among adults with CF than in the general population or among patients with chronic obstructive pulmonary disease. The SGRQ is a valid instrument for analyzing health-related quality of life in adults with CF as it discriminates very well between different degrees of severity of pulmonary impairment and also have an appropriate intern consistency.

Assessment of nutritional status in adult patients with cystic fibrosis: Whole-body bioimpedance vs body mass index, skinfolds, and leg-to-leg bioimpedance

OBJECTIVE

To investigate whether body mass index (BMI) or body fat percentage estimated from BMI, skinfolds, or leg-to-leg bioimpedance are good indicators of nutritional status in adult patients with cystic fibrosis. Body fat percentage measured by whole-body bioimpedance was used as the reference method.

DESIGN

Cross-sectional study using four methods to estimate body fat percentage. All patients filled out a food frequency and a physical activity questionnaire for assessment of their habitual food intake and energy requirements, respectively.

SUBJECTS/SETTING

Thirty-five adult patients (23 men/12 women) with cystic fibrosis, age range 18 to 46 years, were measured during their yearly visit at the outpatient clinic of the Cystic Fibrosis Center in Utrecht, the Netherlands.

STATISTICAL ANALYSIS

Mean+/-standard deviation was calculated for all measurements and 95% confidence intervals for differences between methods. Bland-Altman plots were used to assess differences between the measures of body composition and Pearson correlation coefficients were calculated to determine the relationships between them, and between the energy requirements and the energy intakes.

RESULTS

For men the whole-body body fat percentage reference was 14.1%+/-3.0, body fat percentage estimated from BMI was 15.8%+/-4.3, body fat percentage estimated from skinfolds was 8.6%+/-4.8, and body fat percentage estimated from leg-to-leg bioimpedance was 13.1%+/-4.9. For women the whole-body body fat percentage reference was 24.0%+/-5.9, body fat percentage estimated from BMI was 25.1%+/-4.0, body fat percentage estimated from skinfolds was 17.0%+/-4.8, and body fat percentage estimated from leg-to-leg bioimpedance was 25.0%+/-6.9. Body fat percentage estimated from BMI and body fat percentage estimated from skinfolds were significantly different from the reference value for body fat percentage (P <.05). The correlation coefficients between the reference body fat percentage and body fat percentage estimated from BMI, from skinfolds, and from leg-to-leg bioimpedance were all more than 0.72. In all but one patient, nutritional status was correctly assessed by BMI: those with a BMI less than 18.5 had body fat percentage less than 10% (men) or less than 20% (women). The mean energy intake of the men was 141% of the Recommended Dietary Allowance as proposed in European and Dutch guidelines. The mean energy intake of the women was 94% of the Recommended Dietary Allowance.

CONCLUSIONS

A simple calculation of BMI is adequate to diagnose nutritional status in adult patients with cystic fibrosis. Bioimpedance measurements are only needed when nutritional therapy specifically focuses on lean body mass.

Nitric oxide and protein nitration in the cystic fibrosis airway

Cystic fibrosis (CF), characterized by chronic airway infection and inflammation, ultimately leads to respiratory failure. Exhaled nitric oxide (NO), elevated in most inflammatory airway diseases, is decreased in CF, suggesting either decreased production or accelerated metabolism of NO. The present studies performed on two groups of CF patients provide further support for a disordered NO airway metabolism in CF respiratory tract disease. Despite confirmation of subnormal NOS2 in the CF airway epithelium, alternative isoforms NOS1 and NOS3 were present, and inflammatory cells in the CF airway expressed abundant NOS2. Increased immunohistochemical staining for nitrotyrosine was demonstrated in lung tissues from patients with CF as compared to control. To our knowledge, this is the first report localizing nitrotyrosine in diseased CF lung tissue. While the relative NOS2 deficiency in CF respiratory tract epithelium may contribute to the lower expired NO levels, these results suggest that increased metabolism of NO is also present in advanced CF lung disease. The significance of altered NO metabolism and protein nitration in CF remains to be fully elucidated.