The effect of rounding-off age on the calculated prevalence of anthropometric indices of malnutrition in children aged 2-5 years

For children, two of the anthropometric indices used to assess nutritional status, weight-for-age and height-for-age, depend on the accurate estimation of the child's age. The effect of using age as either last attained year or as last attained year rounded up with half a year in the calculation of prevalence of malnutrition was looked at, using data of children (n= 208), aged between 2 and 5 years,living in the vicinity of the planned Maguga Dam, near Piggs Peak in Swaziland. Date of birth was not known for 41.3% of the children. For children whose date of birth was not known, using age as either last attained year or last attained year rounded up with half a year in the calculation of anthropometric indices profoundly affected the estimated prevalence of malnutrition in the population. The magnitude of malnutrition was lower when age was taken as last attained year. To ensure correct interpretation and use of anthropometric data it is imperative that the methods used to calculate ages are correctly specified and recorded in all documents.