Energy Expenditure and Genotype of Children with Cystic Fibrosis

Abstract

FFM, fat-free mass SF, skinfold TBW, total body water FQ, food quotient RQ, respiratory quotient 2H 2 0 , deuterium oxide rC0 2 , mean daily CO 2 production Abbreviations CF, cystic fibrosis REE, resting energy expenditure TEE, total energy expenditure FVC, forced vital capacity FEV.. forced expiratory volume in 1 s FEF 25-75' forced expiratory flow between 0.25 and 0.75 s 2H, deuterium 180,oxygen-18 BW, body weight ABSTRACT. 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, pancreaticinsufficient children with CF (n =25) and control children (n = 25) of similar age, gender, and weight. The effect of the most common genotype, homozygousaF508, 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 (aF508 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 aF508 homozygous CF subgroup compared with controls. The total energy expenditure increase in aF508 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. (Pediatr Res 35: 451-460, 1994) CF, a common lethal genetic disorder with an autosomal recessive pattern of inheritance, is caused by mutations in the CF transmembrane conductance regulator gene (1-3). Generalized exocrine gland dysfunction results in abnormalities in several organ systems (4). In addition to the excessive losses of sodium chloride in sweat, abnormal mucus in the lungs contributes to the development of chronic obstruction, infection, and inflammation. Exocrine pancreatic insufficiency occurs in more than 85% of patients with CF, and, despite enzyme replacement therapy, malabsorption of fat and micronutrients may occur. According to a 1990 CF Foundation report, about 50% of patients cared for in the 114 organized CF centers had growth failure, with weight and/or height less than the 10th percentile for age and gender (5). CF-related growth failure is often attributed to chronic lung disease, although this causal relationship is not established.Malnutrition may be caused b...

Resting energy expenditure in females with cystic fibrosis: Is it affected by puberty?

“…However, importantly, this increase in REE was unrelated to menarche or the phase of the menstrual cycle. Many studies have described that children with CF have a higher REE than controls (Shepherd et al, 1988;Fried et al, 1991;Girardet et al, 1994;Tomezsko et al, 1994;Thomson et al, 1996;Zemel et al, 1996;Allen et al, 2003). Our finding that females with CF have a higher REE compared with controls is consistent with previous studies describing raised REE in females with CF (Zemel et al, 1996;Allen et al, 2003).…”

“…This has been confirmed by in vitro cell studies (Feigal and Shapiro, 1979) and by in vivo EE measurements of infants, children, adolescents and adults with CF (Shepherd et al, 1988;Fried et al, 1991;Girardet et al, 1994;Tomezsko et al, 1994;Thomson et al, 1996;Zemel et al, 1996;Allen et al, 2003). The evidence of whether the underlying disease or acquired factors (infection, lung disease) are the cause of this increased EE is not completely clear.…”

Energy cost of physical activity in cystic fibrosis

“…There is some evidence that this energy metabolism disorder is genetically conditioned (O'Rawe et al, 1992;Thomson et al, 1996), however the current study did not support this hypothesis. There was no relationship between REE and genotype, which is consistent with others (Fried et al, 1991;Tomezsko et al, 1994). Researchers have also suggested that the increase in REE is related to pulmonary function (Vaisman et al, 1987a,b;Buchdahl et al, 1988;Fried et al, 1991;Amin & Dozor, 1994), however this study did not ®nd any relationship between REE and FEV 1 or FVC.…”

“…Spicher et al, (1991) found no differences in the TEEaREE ratios between patients and controls. Tomezsko et al, (1994) also found no differences between pre-pubertal children with mild lung disease and CF and healthy controls, however they did ®nd a signi®cant difference between the DF508 homozygous subgroup and the mixed heterozygous group of patients. The current results did not demonstrate any differences in ECA between patients in different genotype subgroups.…”

“…Using the heart-rate method, researchers (Spicher et al, 1991) have found that in free-living conditions, TEE in patients with CF is not higher than in control subjects. Alternatively, using the doubly labelled water method, others (Tomezsko et al, 1994) have found TEE in CF is 15 ± 18% greater than in healthy age-matched controls. Only one study to date has examined the amount of energy expended by patients with CF during physical activity per se (Grunow et al, 1993).…”