• Nutrition
• Obesity

Mid-upper arm circumference (MUAC) has a long history as a simple and valuable anthropometric marker of undernutrition, of particular value in resource-poor settings.1 Traditionally, low MUAC has been seen as a proxy for low fat-free mass,1 necessary because accurate measurement of fat-free mass in children is usually impractical in both clinical settings and resource-poor settings.

An emerging body of evidence suggests that MUAC may have value beyond its traditional application in the assessment of undernutrition. The paper by Whitfield et al2 notes that accurate measurement of body weight is often not possible in resource-poor settings, and this is important clinically because it substantially increases the risk of inaccurate drug dosage (where dosage is dependent on body weight). Whitfield et al2 describe a study which suggests that MUAC, when combined with other anthropometric measures, could be a useful and accurate way of estimating body weight in children.

In a sample of 775 predominantly HIV positive children and adolescents (from 18 months to 12 years of age) from Botswana, Whitfield et al made a range of anthropometric measures (height or length, ulnar and tibial lengths, MUAC and triceps skinfold, …