THE DEVELOPMENT OF MUAC-FOR-AGE REFERENCE DATA RECOMMENDED BY A WHO EXPERT COMMITTEE

Low mid-upper-arm circumference (MUAC), determined on the basis of a f ixed cut-off value, has commonly been used as a proxy for low weight-f or-height (wasting). The use of a fixed cut-off value was based on the observation that MUAC showed small age- and sex-specific differences. However, in 1993, a WHO Expert Committee concluded that age independe nce is not reflected in the true pattern of mid-upper arm growth, reco mmended the use of MUAC-for-age, and presented age- and sex-specific M UAC reference data developed with observations obtained from a represe ntative sample of children in the USA aged 6-59 months. In this articl e, we explain the methodology for the development of these data, prese nt age- and sex-specific growth curves and tables and discuss the appl ications and limitations of MUAC as a nutritional indicator. To develo p the reference data, estimates were first obtained for the mean and s tandard deviation of MUAC for each month of age using 7-month segmenta l regression equations, a 5th-degree and a 3rd-degree polynomial in ag e was then used to describe the mean and standard deviation, respectiv ely, of MUAC-for age. These curves show important age-specific differe nces, and significant sex-specific differences for boys and girls <24 months of age. Correct interpretation of MUAC with regard to nutrition al status requires the use of MUAC-for-age reference data such as thos e presented here.