Assuring Pediatric Nutrition in the Community

FREQUENTLY ASKED QUESTIONS:
Assessment of Nutritional Status - Weight-age, height-age, and percent ideal body weight

How are weight-age, height-age, and percent ideal body weight being used? What populations can they be used for? Have they been validated? I am familiar with their use in assessing protein-energy malnutrition (Waterloo and Gomez)--are there disadvantages in applying them to other populations?

Weight and length/height are compared to population standards (CDC growth charts) as an assessment of nutritional status. Using weight-age, height-age and percent ideal body weight as comparisons, classification systems have been established for estimating degree of undernutrition.

Weight-age: age at which weight is at the 50th percentile on CDC chart. In acute malnutrition, this may be lower than chronological age.

Height-age: age at which length/height is at the 50th percentile on CDC chart. This is often reduced in chronic malnutrition (stunting).

Percent weight-age: child's actual weight divided by weight at the 50th percentile for his/her age

Waterloo used height-age and weight for height to assess chronic and acute malnutrition. Using height- or weight- age to estimate desirable body weights for children with special health care needs has not been supported in the literature, nor has the use of height- or weight- age to estimate energy requirements.

Gomez used percent weight-age to assess malnutrition. This method of assessment does not consider the effects of height on desirable body weight. It is not appropriate to use this method in populations with alterations in body composition that are not related to nutritional status (for example, children with degenerative muscle-wasting disorders).

References

Waterlow JC. Classification and definition of protein-calorie malnutrition. Br Med J, 1972; 3: 566-69