Readers may find helpful an article by the WHO Working
          Group on Infant Growth, one of whose members is Katherine
          Dewey, printed in the Bulletin of the World Health
          Organization 1995;73(2):165-174:  An evaluation of infant
          growth: the use and interpretation of anthropometry in
          infants. <In reviewing the growth of infants who live under
          favourable conditions and are fed according to WHO feeding
          recommendations, the WG found significant differences
          between the growth patterns of these infants and the
          patterns reflected in the NCHS-WHO international reference.
          Given the short- and long-term consequences of growth
          failure, and the dangers of both the premature introduction
          of complementary food and their undue delay--described as
          the "weanling's dilemma"--the WG concluded that use of the
          current WHO-NCHS reference appears to accentuate the
          difficulty of avoiding these extremes rather than to help
          ensure optimal infant nutritional management. <The WG
          identified the following requirements: (a) a new reference
          which will enhance the nutritional management of infants;
          (b) the reference population should reflect current health
          recommendations because of the frequent use of such
          reference data as standards; (c) evaluation, in a broad
          range of settings, of the practical utility of using
          reference data based on infants for whom the WHO feeding
          recommendations are being followed; (d) close investigation
          of the effects of different complementary foods on the
          growth of infants who are being fed according to the WHO
          recommendations; (e) criteria for evaluating abnormal growth
          patterns; (f) research for identifying proxy measures for
          length; and (g) evaluation of reference data based on other
          anthropometric measurements, such as skinfold thickness and
          arm and head circumferences.> For information, the current
          NCHS (National Center for Health Statistics, USA)-WHO
          reference for infants is based on the Fels Longitudinal
          Study, conducted in Yellow Springs, Ohio, from 1929 to 1975.
          <There are several limitations in these reference data.
          First, the sample was limited to Caucasian infants from
          predominantly middle-class families.  Second, the
          measurements were taken every 3 months rather than every
          month, which is not ideal for characterizing the shape of
          the growth curve, particularly during the first 6 months of
          life. Lastly, most of the infants in the Fels study were
          bottle-fed; of those who were breast-fed, very few were
          breast-fed for more than 3 months.>

          Jim Akre, Nutrition unit, WHO, Geneva