Nutrional status and dietary factors in cystic fibrosis patients with delta F508 mutation

Association between cystic fibrosis transmembrane regulator genotype and clinical outcomes, glucose homeostasis indices and CF-related diabetes risk in adults with CF

People living with cystic fibrosis (pwCF) homozygous for F508del present more severe phenotypes. PwCF with compound heterozygous genotypes F508del /A455E and F508del /L206W may have milder cystic fibrosis (CF) phenotypes. We compared F508del homozygotes and common compound heterozygotes (F508del and a second pathogenic variant) in adult patients. Nutritional, pulmonary function and glucose homeostasis indices data were collected from the prospective Montreal CF cohort. Two-hundred and three adults with CF having at least one F508del variant were included. Individuals were divided into subgroups: homozygous F508del/F508del (n=149); F508del/621+1G>T (n=17); F508del/711+1G>T (n=11); F508del/A455E (n=12); and F508del/L206W (n=14). Subgroups with the F508del/L206W and F508del/A455E had a lower proportion with pancreatic exocrine insufficiency (p<0.0001), a higher fat mass (p<0.0001), and lower glucose area under the curve (AUC) (p=0.027). The F508del/L206W subgroup had significantly higher insulin secretion (AUC; p=0.027) and body mass index (p<0.001). Pulmonary function (FEV1) was significantly higher for the F508del/L206W subgroup (p<0.0001). Over a median of 7.37 years, the risk of developing CFRD in 141 patients was similar between groups. PwCF with heterozygous F508del/L206W and F508del/A455E tended to have pancreatic exocrine sufficiency, better nutritional status, improved pulmonary function and better diabetogenic indices, but this does not translate into lower risk of CF-related Diabetes.

Evaluation of anthropometry as an alternative to DXA as predictor of low bone mineral density in children and adolescents with cystic fibrosis

BACKGROUND & AIMS

Low bone mineral density (BMD) for age in people with Cystic Fibrosis (CF) is associated with worse nutritional status. The aim of this study is to assess body composition by anthropometry as a predictor of BMD in people with CF.

METHODS

Multicenter cross-sectional study with 39 people aged 5 and 20 years with CF. BMD was assessed by dual energy x-ray emission (DXA) in the incidence of the total body less head (TBLH) and the TBLH Z-score (Z-TBLH) was calculated, adjusted by sex, age, height and ethnicity. Anthropometry was assessed by weight, height, mid-upper arm circumference (MUAC) and triceps skinfold (TSF). Arm muscle area (AMA) and Body Mass Index (BMI) were calculated. Lean mass (LM), fat mass (FM) and free-fat mass (FFM) were identified by DXA. The molecular analysis method by sequencing was used to identify and classify the participants regarding the presence of the F508del pathogenic variant of the CFTR gene. Statistical models of simple and multiple linear regression were created to establish the predictive power of Z-TBLH in the variables.

RESULTS

Average age of the participants was 13.31 ± 3.86 years, 59% of whom were male. They showed more LM (30.97 Kg ± 11.29) than females (23 Kg ± 6.73). 20 of 30 participants (66.7%) had at least copy of F508del. Among the multiple models, adjusted by height, age and sex, it found BMI (R² = 0.367), Weight (R² = 0.220), AMA (R² = 0.338) as significant predictors of Z-TBLH. The final model composed of AMA, TSF and Age (p = 0.001; R² = 0.381) had AMA and Age as significant predictors. AMA was associated with an increase in the BMD Z-score in the participants studied. 66.7% of genetically tested participants had the F508del pathogenic variant. The presence of the F508del variant was associated with worse nutritional status.

CONCLUSION

A statistical model composed of the values of AMA, TSF and Age can predict Z-TBLH, as well as anthropometric variables Weight, or BMI, or AMA associated with height, age and sex, in children and adolescents aged 5-20 years old, of both sexes. Anthropometric markers, as they are easy and relatively inexpensive to obtain, it is a promising alternative to the use of DXA in predicting BMD in these people with CF.

Dietary intake of energy-dense, nutrient-poor and nutrient-dense food sources in children with cystic fibrosis

BACKGROUND

Prescription of a high-energy, high-fat diet is a mainstay of nutrition management in cystic fibrosis (CF). However, families may be relying on energy-dense, nutrient-poor (EDNP) foods rather than nutrient-dense (ND) foods to meet dietary targets. We aimed to evaluate the relative contribution of EDNP and ND foods to the usual diets of children with CF and identify sociodemographic factors associated with higher EDNP intakes.

METHODS

This is a cross-sectional comparison of children with CF aged 2-18 years and age- and gender-matched controls. Dietary intake was assessed using the Australian Child and Adolescent Eating Survey (ACAES) food frequency questionnaire.

RESULTS

Children with CF (n = 80: 37 males; mean age 9.3 years) consumed significantly more EDNP foods than controls (mean age 9.8 years) in terms of both total energy (median [IQR]: 1301 kcal/day (843-1860) vs. 686 kcal/day (480-1032); p < 0.0001), and as a proportion of energy intake (median [IQR]: 44% (34-51) vs. 31% (24-43); p < 0.0001). Although children with CF met their estimated energy requirements (median [IQR]: 158% (124-187) vs. 112% (90-137); p < 0.0001) and their diets were high in fat (median [IQR]: 38% (35-41) vs. 34% (32-36); p < 0.0001), this was largely attributable to EDNP foods. High EDNP intakes (≥10 serves/day) were associated with socioeconomic disadvantage (p = 0.01) and rural residential location (p = 0.03).

DISCUSSION

The energy- and fat-dense CF diet is primarily achieved by overconsumption of EDNP foods, rather than ND sources. This dietary pattern may not be optimal for the future health of children with CF, who are now expected to survive well into adulthood.

Modeling cystic fibrosis disease progression in patients with the rare CFTR mutation P67L

BACKGROUND

The progression of cystic fibrosis (CF) in patients with the rare mutation P67L was examined to determine if it induced a milder form of CF compared to the common severe ΔF508 mutation.

METHODS

Parameters of lung function, level of bacterial infection, nutritional status and hospitalization were used to represent CF progression. Age at diagnosis and pancreatic status were used to assess CF presentation. Analysis of data from the CF Canada Registry collected over a 15-year period included 266 ΔF508/ΔF508 homozygote patients from CF clinics in Atlantic Canada and 26 compound heterozygote patients with the rare P67L mutation from clinics across Canada.

RESULTS

Late age at diagnosis, high incidence of pancreatic sufficiency, maintained Body Mass Index (BMI) with age, delayed life-threatening bacterial infection, and fewer days in hospital were observed for P67L heterozygote patients included in this study. Although the decline of lung function did not differ from ΔF508 homozygotes, the fact that a greater proportion of P67L heterozygotes live to an older age suggests that lung function is not the primary factor determining CF progression for P67L heterozygote patients.

CONCLUSION

The P67L mutation is associated with a mild disease, even when combined with the severe ΔF508 mutation.