Journal of Cystic Fibrosis 1 (2002)

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1 Journl of Cystic Fibrosis 1 (2002) Assessment of nutritionl sttus in children with cystic fibrosis: conventionl nthropometry nd bioelectricl impednce nlysis. A cross-sectionl study in Dutch ptients, b c Michel Groeneweg *, Suzn Tn, Annemieke M. Boot, John C. de Jongste, Jn Bouquet, Mrten Sinsppel Deprtment of Peditrics, Section of Gstroenterology, Ersmus Medicl Centre Rotterdm, Sophi Children s Hospitl, Rotterdm, The Netherlnds b Deprtment of Peditrics, Section of Endocrinology, Ersmus Medicl Centre Rotterdm, Sophi Children s Hospitl, Rotterdm, The Netherlnds c Deprtment of Peditrics, Section of Pulmonology, Ersmus Medicl Centre Rotterdm, Sophi Children s Hospitl, Rotterdm, The Netherlnds Abstrct Bckground: Assessment of nutritionl sttus in children with cystic fibrosis (CF) is cliniclly relevnt. Methods to mesure nutritionl sttus should be relible nd non-invsive, nd reference vlues should be vilble. Aim: To compre weight nd height mesurements nd mesurements of specific body comprtments in children with CF. Methods: In cross-sectionl survey of 58 children with CF (28 femles), we compred height nd weight (expressed s: weight-for-height, body mss index (BMI), height-for-ge nd weight-for-ge) with ft mss (skinfold sum (SFS)), muscle mss (upper rm circumference (UAC)) nd bioelectricl impednce nlysis (BIA). Results were expressed s Z-scores, using Dutch reference vlues. Results: BMI nd weight-for-height were within the norml rnge (men Z-score (rnge): y0.13 (y1.5, 2.7) nd y0.02 (y1.7, 2.8)). Weight nd height corrected for ge were below norml (men Z-score (rnge): y0.79 (y2.4, y0.05) nd y1.2 (y2.8, 1.4) (P-0.01)). Len body mss by skinfold sum (LBM sfs), UAC nd BIA were lso significntly below reference vlues (men Z-score (rnge): y0.9 (y2.2, 1.8), y0.95 (y2.4, 1.8) nd y1.1 (y3.6, 1.0) (P-0.01)). Len body mss (LBM) by BIA correlted with LBM sfs. BIA systemticlly underestimted LBM in both CF ptients nd in control subjects. Conclusion: Nutritionl sttus of children with CF must be evluted, using ge-corrected weight nd height expressed in Z-score. LBM estimted by SFS, UAC nd by BIA pper to be useful, lthough longitudinl studies in CF children should be performed to evlute their clinicl significnce in detecting chnges in nutritionl sttus Europen Cystic Fibrosis Society. Published by Elsevier Science B.V. All rights reserved. Keywords: Cystic fibrosis; Nutritionl sttus; Bioelectricl impednce nlysis 1. Introduction In cystic fibrosis (CF), survivl is determined both by progressive pulmonry disese s well s by nutritionl sttus. Pulmonry disese increses resting energy Abbrevitions: CF, cystic fibrosis; REE, resting energy expenditure; LBM sfs, len body mss by skinfold sum; LBM bi, len body mss by bioelectricl impednce nlysis; FEV 1, forced expirtory volume in 1 s; FVC, forced vitl cpcity; BIA, bioelectricl impednce nlysis; SFS, skinfold sum; UAC, upper rm circumference; BMI, body mss index; RI, resistnce index; CI, confidence intervl; S.D., stndrd devition *Corresponding uthor. Julin Children s Hospitl, P.O. Box 60605, 2506 LP The Hgue, The Netherlnds. Tel.: q E-mil ddress: m.groeneweg@plnet.nl (M. Groeneweg). expenditure nd it reduces ppetite. In ddition, poor nutritionl sttus increses the risk for pulmonry infections. So prt from slowing down the deteriortion of pulmonry function, n optiml nutritionl sttus should be preserved in order to improve prognosis w1,2x. Assessment of nutritionl sttus hs been the subject of extensive studies in CF w3 5x. In clinicl prctice nutritionl sttus is derived from mesurements of weight nd height nd by compring these dt with norml vlues for weight-for-height, height-for-ge nd weight-for-ge. These vlues my be unrelible for ssessment of nutritionl sttus in CF. As n exmple, CF ptient with severe muscle wsting nd scites cn hve weight-for-height within norml rnge, becuse /02/$ - see front mtter 2002 Europen Cystic Fibrosis Society. Published by Elsevier Science B.V. All rights reserved. PII: S Ž

2 M. Groeneweg et l. / Journl of Cystic Fibrosis 1 (2002) the scites compenstes for the loss of muscle mss w3 5x. Mesurement of ft mss, len body mss (LBM) nd muscle mss probbly re more relible estimtes of nutritionl sttus w6x. The present study ws imed t evluting weight nd length mesurements with mesurements of specific body comprtments (LBM, ft mss, muscle mss) in children with CF. In this study we will ddress two questions: wht body comprtments re most ffected in CF nd wht is the reltion between the estimtes of LBM derived from bioelectricl impednce nlysis (LBM bi) nd LBM derived from skinfold thickness mesurements (LBM sfs)? 2. Ptients nd methods In cross-sectionl study, nutritionl sttus ws evluted in 58 children with CF (28 girls nd 30 boys; ge rnge 4 18 yers). Ptients were rndomly recruited from the Cystic Fibrosis Center outptient clinic of the Sophi Children s Hospitl Rotterdm. Mesurements were performed in the outptient clinic Clinicl prmeters Disese severity ws ssessed by pulmonry function nd Shwchmn score w7x. All ptients were in cliniclly stble condition t the time of the mesurements. Pulmonry function ws ssessed within 3 months before the investigtions in 41 of 58 ptients. Pulmonry function ws expressed s forced expirtory volume t 1 s (FEV 1) nd s forced vitl cpcity (FVC). Vlues were expressed s percentge of the predicted vlue w8x. Shwchmn scores were clculted in 53 ptients Assessment of nutritionl sttus Weight nd height were determined, using stndrd techniques w14x: height ws mesured, using stdiometer. The ptient ws mesured without shoes nd socks nd the top of the hed ws in contct with the hedbord of the stdiometer. The hed ws held in the Frnkfurt plne, nd slight pressure (corresponding to ;0.5 kg) ws exerted on the hedbord. Weight ws mesured fter the outer clothing nd socks of the ptients were removed. An electronic scle with digitl reding ws used, ccurte to 10 g. As mesure of ft mss, skinfold sum (SFS) ws determined (skinfold cliper: John Bull, British Indictors, UK) s described by Lohmn et l. w9x. Skinfold thickness of four res (triceps, biceps, subscpulr, suprilicl skinfolds) were mesured twice by the sme investigtor nd their mens were dded. Ft mss ws clculted, ccording to Weststrte nd Deurenberg w10x. LBMsfs ws clculted by subtrcting ft mss from body weight. As mesure of muscle mss nd ft mss, upper rm circumference (UAC) ws determined on the non-dominnt upper rm, s described by Weststrte nd Deurenberg w10x. LBMbi ws lso determined by using bioelectricl impednce nlysis (BIA) (BIA 101yS, RJC Co., Detroit, MI) w13x. Totl body impednce (R) ws ssessed in triplicte with n intervl of 5 min w11 13x. On the bsis of R, the resistnce index (RI) ws 2 clculted (RIs(height) yr). Weight nd height were expressed s Z-scores for weight-for-height, body mss 2 index (BMIsweightyheight ), weight-for-ge nd height-for-ge. UAC nd LBMsfs were expressed s Z- scores, using ge-relted norml vlues for Dutch children w14x. LBMbi ws clculted, using computer progrm, provided by the mnufcturer (RJC Co.). Seprte progrms for children (4 12 yers), dolescents (13 16 yers) nd dults (17 yers nd older) were used. This progrm clcultes LBM by entering the BIA prmeters (impednce nd rectnce), in ddition to ge, sex, weight nd height. These results were compred with dt from helthy Dutch control subjects, using the following equtions: for boys: LBMs(ge=3.2658)y (S.D.s3.37); for girls: LBMs(ge=2.0572)q (S.D.s4.02) w15x. On the bsis of these norml vlues (nd their S.D.) Z- scores of LBM could be clculted. bi 2.3. Sttisticl nlysis Bseline differences between boys nd girls were tested using the Student-t test (ge) nd using the Wilcoxon signed rnksum test (% FEV 1, % FVC, Shwchmn score). For the totl group of 58 ptients men Z-scores for weight-for-height, BMI, weight-forge, height-for-ge, UAC nd LBM bi "95% confidence intervl (CI) were clculted. Men difference from Zs 0 ws tested, using the Student-t test. Correltion between Z-scores ws tested using Person correltion nlysis. LBMsfs nd LBMbi were clculted for boys nd girls seprtely nd the results were compred with vlues of reference group of helthy Dutch children w15x. Difference in LBM between boys nd girls ws tested using the Wilcoxon signed rnksum test. 3. Results Bseline chrcteristics re listed in Tble 1. All ptients were pncretic insufficient. Men ge nd pulmonry function were similr between boys nd girls. Shwchmn scores were lower in girls compred with boys (Ps0.04). Men Z-scores for BMI nd for weight-for-height were not different from Z-scores0. However, men Z- scores for height-for ge, weight-for-ge, SFS, UAC nd LBMbi were ll significntly lower thn Zs0. Men Z- scores"ci re shown in Fig. 1 nd in Tble 2. In Figs.

3 278 M. Groeneweg et l. / Journl of Cystic Fibrosis 1 (2002) Tble 1 Ptient chrcteristics Boys Girls P-vlue (ns30) (ns28) Age 10.0"4.3 (4 18) 10.4"4.0 (4 18) 0.2 % FVC 96"19 (62 131) 92"20 (61 125) 0.6 b %FEV 1 83"22 (56 122) 76"23 (23 113) 0.4 b Shwchmn score 87"10 (55 100) 80"11 (55 95) 0.04 b Student-t test. b Wilcoxon signed rnksum test. Tble 2 Men Z-scores of children with CF (ns58) Men Z-score Rnge P-vlue BMI y0.13 (1.1) y1.5, 2.7 n.s. Weight-for-height y0.02 (1.1) y1.7, 2.8 n.s. Height-for-ge y1.2 (0.8) y2.8, Weight-for-ge y0.79 (0.9) y2.4, y LBM sfs y0.9 (0.9) y2.2, UAC y0.95 (0.8) y2.4, LBM bi y1.1 (1.0) y3.6, Vlues re expressed s men Z-scores (S.D.) nd rnge. Student-t test: men Z-scores0. Fig. 1. Men Z-scores of totl group of ptients with CF (ns58). Men Z-scores"CI. BMI, body mss index; W-H, weight-for-height; H-A, height-for-ge; W-A, weight-for-ge; SFS, len body mss by skinfold sum; UAC, upper rm circumference nd BIA, bioelectricl impednce nlysis. 2 nd 3 weight nd height of ll ptients re plotted in reference grphs for weight-for-height nd for heightfor-ge, derived from dt of helthy Dutch children w14x. Weight-for-height plots show tht 10 out of 30 boys, nd 16 out of 28 girls re below Zs0 (Fig. 2). In the height-for-ge plots 27 out of 30 boys nd 27 out of 28 girls re below Zs0 (Fig. 3). BMI correlted significntly with LBM sfs, UAC nd LBM bi (rs0.55, 0.75 nd 0.67: P-0.01). LBMbi correlted significntly with LBMsfs nd with UAC (rs 0.67 nd 0.69: P-0.01). In boys with CF, LBMbi ws 27.4"9.9 (men"s.d.), which ws significntly lower thn LBMbi of helthy Dutch boys: 32"13 kg (men"s.d.: Ps0.001) w15x. In girls with CF comprble difference is present: 23.5"8.6 kg vs. 27.2"8.8 kg (men"s.d.) Ps0.001). LBMsfs ws 32.0"1.1 kg in CF boys, nd 36.6"14.6 kg in helthy Dutch boys (P-0.001). InCF girls: 30.3"12.0 kg vs. 33.6"13.1 kg (Ps0.004). Although LBMbi nd LBMsfs re correlted, constnt Fig. 2. Weight-for-height percentiles of boys (ns30) nd girls (ns28) with CF. Weight-for-height curves for boys (left grph) nd for girls (right grph). The middle line represents Zs0; the upper nd lower line represent two times the S.D. Every single dot represents one ptient.

4 M. Groeneweg et l. / Journl of Cystic Fibrosis 1 (2002) Fig. 3. Height-for-ge percentiles of boys (ns30) nd girls (ns28) with CF. Height-for-ge curves for boys (left grph) nd for girls (right grph). The middle line represents Zs0; the upper nd lower line represent two times the S.D. Every single dot represents one ptient. difference in fvour of LBMsfs is present in both CF ptients nd in helthy controls. 4. Discussion In CF, nutritionl sttus hs significnt prognostic influence on the outcome of the disese w1,2x. In the present cross-sectionl study we compred weight nd height mesurements of children with CF with estimtes of specific body comprtments: ft mss, LBM nd muscle mss. Our results indicte, tht conventionl weight-for-height nd BMI plots re well within norml rnge (Z-scores0), despite significnt decrese in LBM in these children. These findings indicte tht these mesures re unrelible for nutritionl ssessment in CF. However, weight nd height corrected for ge show significntly decresed Z-scores. In ddition, Z-scores for LBM sfs, LBMbi nd UAC re lso significntly decresed. Our results re in greement with erlier studies, in which weight-for-ge nd height-for-ge Z- scores were reduced in CF w5,16,17x. Results of SFS nd UAC support the conclusion tht children with CF suffer both from ft- nd muscle-mss depletion. BIA nlysis provides simple nd non-invsive but indirect quntittive mesure of LBM. Totl body wter mesurements using the deuterium dilution method (D2O) show tht totl body wter is significntly correlted with the RI of BIA in CF w11,12x. Our study shows tht Z-scores of LBMbi re significntly corre- lted with LBMsfs nd with UAC. However, in bsolute figures, LBMbi re constntly lower thn LBM sfs. A comprble difference is found in helthy Dutch children, which confirms tht this difference is probbly cused by difference in methodology, rther thn reflection of CF itself w12,13,18x. In conclusion, Z-scores for weight-for-height nd for BMI re unrelible for the detection of mlnutrition in children with CF. In our outptient clinic nutritionl sttus cn be ssessed by height-for-ge nd weight-forge. The guidelines for the confirmtion of mlnutrition ( decrese in Z-score for weight-for-ge of )0.5 in 3 months) cn be used in this respect w6x. SFS nd UAC estimtes of LBM cn be used for CF ptients to define clinicl mlnutrition: more thn 1.0 point decrese in Z-score in 3 months w6x. BIA is relible technique in its bility to generte LBM estimtes, which correlte well with other mesures of LBM. Longitudinl studies in CF children should be performed, in order to evlute reproducibility of LBM estimtes by BIA nd its ccurcy to detect chnges in nutritionl sttus w16,19x. References w1x Corey M, Mc Lughlin FJ, Willims M. A comprison of survivl, growth nd pulmonry function in ptients with cystic fibrosis in Boston nd Toronto. J. Clin. Epidemiol. 1988;41: w2x Durie PR, Penchrz PB. Nutrition. In: Cystic fibrosis. Br Med Bull 1992;48: w3x Heusler G, Frisch H, Wldhor H, Gotz M. Perspectives of longitudinl growth in cystic fibrosis from birth to dult ge. Eur. J. Peditr. 1994;153: w4x Mhney MC, McCoy K. Developmentl delys nd pulmonry disese severity in cystic fibrosis. Hum. Biol. 1986;58: w5x McNughton SA, Shepherd RW, Greer RG, Cleghorn GJ, Thoms BJ. Nutritionl sttus of children with cystic fibrosis mesured by totl body potssium s mrker of body cell mss: lck of sensitivity of nthoropometric mesures. J. Peditr. 2000;136: w6x Rmsey BL, Frrell PM, Penchrz P. Nutritionl ssessment nd mngement in cystic fibrosis: consensus report. Am. J. Clin. Nutr. 1992;55:

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