Original Communication The potential of near infra-red interactance for predicting body composition in children NJ Fuller 1 , O Dewit 2 and JCK Wells 1 * 1 MRC Childhood Nutrition Research Centre, Institute of Child Health, London, UK; and 2 Clinical Pharmacology Department, SmithKline Beecham Pharmaceuticals, Harlow, Essex, UK Objective: To establish whether near infra-red interactance (NIRI) has potential for use instead of skinfold thickness (SFT) measurements in the assessment of body composition in young children. Design: Strengths of relationships were established between NIRI or SFT measurements and four-component model (4-CM) assessments of body composition. Subjects: Nineteen boys and 19 girls, aged 8 – 12 y. Measurements: 4-CM estimates of body composition were obtained from measurements of body weight, body volume, bone mineral content and total body water. SFT and NIRI were measured at the same four recognized sites (biceps, triceps, subscapular and suprailiac). Results: All children subjectively expressed a preference for NIRI rather than SFT calipers. Although SFTs were slightly more strongly and consistently related to 4-CM estimates, NIRI measurements at the biceps, subscapular and sum of four sites were significantly related to body composition indices. Subscapular NIRI measurements were as successful as subscapular SFTs in ranking subjects relative to 4-CM fatness, both techniques being most successful at lower levels of fatness. Conclusion: NIRI has potential for use instead of SFT for estimating body composition in young children. Its contribution may prove to be greatest in sick children in whom SFT measurements may be unwelcome, and weight-for-height indices of little value due to abnormalities of water distribution. However, greater numbers are required to develop child-specific prediction equations and the viability and validity of NIRI in pediatric patients is still to be evaluated. Descriptors: four-component model; body fat; fat-free mass; skinfold thickness European Journal of Clinical Nutrition (2001) 55, 967–972 Introduction There is a need for effective simple, non-invasive and inexpensive techniques for clinical or field assessments of body composition in children. Traditionally, the interpreta- tion of skinfold thickness (SFT) measurements as body composition has fulfilled this role (Brook, 1971; Slaughter et al, 1988; Deurenberg et al, 1990), albeit with some uncertainty (Reilly et al, 1995). However, as health profes- sionals often report distress and poor patient compliance with the use of SFT calipers, which may be perceived as threatening and painful by young children, the utility of alternative techniques may be preferred. Empirical esti- mates from body weight (BWt) and height (Ht) fail to provide reliable indices of nutritional status especially in clinical conditions with variable hydration and density of the fat-free mass (FFM). Furthermore, bio-electrical impe- dance analysis (BIA), for predicting total body water (TBW) in particular, as the water containing body compart- ments conduct the electrical current, may not be universally applicable because of confounding variables, such as inter- ference from nearby equipment, or inappropriate prediction equations that may generate significant bias and variability when applied clinically (Azcue et al, 1993; Bedogni et al, 1996) or in healthy children (Wells et al, 1999). Another development that may have potential for use in children is near infra-red interactance (NIRI) because the light probe placed on the skin surface appears to be less daunting than SFT calipers, with no associated pain. The NIRI technique involves the introduction of infra-red radiation through the skin into the underlying tissues and assessment of the pattern and intensity of the reflected *Correspondence: JCK Wells, MRC Childhood Nutrition Research Centre, Institute of Child Health, 30 Guildford St, London WC1N 1EH, UK. Guarantor: JCK Wells. Contributors: All authors contributed to all aspects of the study. Received 22 November 2000; revised 17 April 2001; accepted 19 April 2001 European Journal of Clinical Nutrition (2001) 55, 967–972 ß 2001 Nature Publishing Group All rights reserved 0954–3007/01 $15.00 www.nature.com/ejcn