Energy expenditure and substrate utilization in adults with cystic fibrosis and diabetes mellitus.

BACKGROUND: The onset of cystic fibrosis-related diabetes mellitus (CFDM) is often associated with a decline in clinical and nutritional status. OBJECTIVE: The purpose of this study was to characterize energy expenditure (EE) and substrate utilization during rest, exercise, and recovery from exercise in patients with CF diagnosed with diabetes mellitus. DESIGN: EE, substrate utilization, minute ventilation, tidal volume, and respiratory rate were calculated by indirect calorimetry durng rest; a 30-min, low-to-medium-intensity exercise bout on a treadmill; and a 45-min postexercise recovery period (in reclining position) in 10 CF, 7 CFDM, and 10 control subjects between 18 and 45 y of age. RESULTS: In all 3 periods, minute ventilation was higher in the CF and CFDM groups than in the control subjects (P < 0.01). During rest and exercise, the CF and CFDM groups maintained EE values at the high end of the normal range of the control subjects. However, during recovery, EE was higher in the CF and CFDM groups than in the control group (P < 0.01). CONCLUSIONS: EE may be higher than usual for the patients with CF and CFDM during periods of recovery from mild exercise or activity because of increased work of breathing consistent with higher ventilatory requirements. This information may be useful for patients receiving nutritional counseling who may choose to exercise regularly, but are concerned about possible weight loss.

Longitudinal, prospective analysis of dietary intake in children with cystic fibrosis.

OBJECTIVES: Prospective, 3-year longitudinal dietary intakes of 25 prepubertal, pancreatic-insufficient children with cystic fibrosis (CF) and mild lung disease, and the intakes of 26 control children were compared, and relationships among energy intake, nutritional status, and pulmonary function were determined. STUDY DESIGN: Intakes from 3-day weighed food records were compared with CF recommendations, recommended dietary allowances (RDA), and the recommendations of the Third National Health and Nutrition Examination Survey (NHANES III). Energy and nutrient intakes were analyzed by repeated-measures analysis of variance. RESULTS: Children with CF consumed more energy than control children (p = 0.025) in terms of calories per day, percentage of RDA by age and by age and weight, energy adjusted for fat malabsorption, and percentage of NHANES III recommendations. Energy intake was similar between boys and girls with CF. The percentage of energy from fat was greater (p = 0.0004) in the CF group (3-year mean, 33%) than in the control group. Height and weight z scores declined in the CF group (p <0.05) with time. Vitamin and mineral intakes were generally adequate in the CF group. CONCLUSIONS: The children in this sample did not consume the CF recommended intakes of 120% RDA for energy or a high-fat (40% of energy) diet. Energy intakes may be insufficient in this group to meet requirements for optimal growth.

Energy expenditure and genotype of children with cystic fibrosis.

Increased energy expenditure, poor dietary intake, and fat malabsorption in patients with cystic fibrosis (CF) frequently lead to growth failure and malnutrition, which are associated with pulmonary failure and decreased survival. The study purpose was to understand better the energy expenditure and requirements in the mild pulmonary disease state in children. Resting and total energy expenditure were measured in 6- to 9-yr-old, pancreatic-insufficient children with CF (n = 25) and control children (n = 25) of similar age, gender, and weight. The effect of the most common genotype, homozygous delta F508, on energy expenditure was also investigated. Dietary intake, degree of fat malabsorption, body composition, physical activity, and clinical status were determined. The CF group had a 9% increase in resting energy expenditure, which was not related to genotype or severity of lung disease. Both CF genotype subgroups (delta F508 homozygous and all others) had a similar, modest resting energy expenditure increase. Total energy expenditure was increased by 12% in the entire CF group and by 23% in the delta F508 homozygous CF subgroup compared with controls. The total energy expenditure increase in delta F508 homozygous children may be related to increased voluntary physical activity, reflecting no activity reduction associated with lung disease, or to an unidentified genotype-related mechanism. The clinical implication is that a detailed physical activity assessment should be evaluated along with resting energy expenditure, either measured or estimated by equations, when daily energy needs are being determined for children with CF.

Body composition of children with cystic fibrosis with mild clinical manifestations compared with normal children.

Because growth and anthropometric measurements are frequently below normal in patients with cystic fibrosis (CF), the body composition of 23 children (6-9 y of age) who had mild manifestations of CF was examined and compared with a control group of 24 subjects similar in age, sex, and weight. Skinfold measurements, total body water (TBW) by deuterium oxide dilution, and total body electroconductivity (TOBEC) were measured. Skinfold and TBW measurements demonstrated that fat mass and fat-free mass did not differ significantly between the two groups. No significant difference in percent body fat was found by using the skinfold equations of Slaughter et al (13.8% vs 15.3%), although percent body fat (TBW method) differed between the groups (P < 0.05). TOBEC measurements (CF, n = 14) were not used in the group comparison. The majority of the methods demonstrated that the CF group achieved normal growth and body composition, with a possible trend of fat depletion.

Dietary intake of healthy children with cystic fibrosis compared with normal control children.

Because a low calorie intake may result in growth failure and malnutrition in patients with cystic fibrosis (CF), the dietary and energy intakes of 22 children with CF who had mild lung disease and excellent Shwachman scores were examined and compared with those of 23 normal control subjects similar in age (5 to 10 years), gender, and weight. The children with CF consumed significantly more calories than the control subjects. Calorie intake was 111 +/- 19.9% (mean +/- SD) of estimated requirements (World Health Organization recommendations) for the CF group and 97 +/- 18.7% for the control group (P = .014). Calories consumed per kilogram of body weight were 117% of World Health Organization (CF) vs 97% (control) (P = .009). Calorie intake compared to the 1989 Recommended Dietary Allowance was 106 +/- 20.6% for the CF group vs 93 +/- 19.1% for the control group. Fat consumed as a percent of total calories was similar: 33.5% (CF) vs 32.2% (control). All children with CF had pancreatic insufficiency and, on average, consumed a large number of pancreatic enzyme supplements, resulting in dietary fat absorption of 86 +/- 12%. It is concluded that these children with CF were able to maintain normal growth and energy stores on a diet that was relatively high in calories compared to control subjects and moderate in percent fat, along with an aggressive pancreatic enzyme supplement regimen.