Adjusting body cell mass for size in women of differing nutritional status.
BACKGROUND
Body cell mass (BCM) may be estimated in clinical practice to assess functional nutritional status, eg, in patients with anorexia nervosa. Interpretation of the data, especially in younger patients who are still growing, requires appropriate adjustment for size. Previous investigations of this general issue have addressed chemical rather than functional components of body composition and have not considered patients at the extremes of nutritional status, in whom the ability to make longitudinal comparisons is of particular importance.


OBJECTIVE
Our objective was to determine the power by which height should be raised to adjust BCM for height in women of differing nutritional status.


METHODS
BCM was estimated by (40)K counting in 58 healthy women, 33 healthy female adolescents, and 75 female adolescents with anorexia nervosa. The relation between BCM and height was explored in each group by using log-log regression analysis.


RESULTS
The powers by which height should be raised to adjust BCM were 1.73, 1.73, and 2.07 in the women, healthy female adolescents, and anorexic female adolescents, respectively. A simplified version of the index, BCM/height(2), was appropriate for all 3 categories and was negligibly correlated with height.


CONCLUSIONS
In normal-weight women, the relation between height and BCM is consistent with that reported previously between height and fat-free mass. Although the consistency of the relation between BCM and fat-free mass decreases with increasing weight loss, the relation between height and BCM is not significantly different between normal-weight and underweight women. The index BCM/height(2) is easy to calculate and applicable to both healthy and underweight women. This information may be helpful in interpreting body-composition data in clinical practice.
MRC Childhood Nutrition Research Centre, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. jwells@ich.ucl.ac.uk
Jonathan C K
JC
Wells
Alexia J
AJ
Murphy
Helen M
HM
Buntain
Ristan M
RM
Greer
Geoffrey J
GJ
Cleghorn
Peter S W
PS
Davies
D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa; D001823:Body Composition; D001827:Body Height; D005260:Female; D006801:Humans; D016014:Linear Models; D009752:Nutritional Status