 Growth
Charts
Monitoring growth of infants and young children is an important
public health measure. When combined with supporting appropriate
nutrition practices such as exclusive breastfeeding, timely complementary
feeding and immunization against common communicable diseases,
growth monitoring is a significant instrument in the reduction
of child mortality and illness. Since the 1970s, the World Health
Organization (WHO) has been recommending that the National Center
for Health Statistics/Centers for Disease Control growth references
be used as international growth standards. These data were collected
between 1929 and 1975, during a time when breastfeeding was in
decline and complementary foods were introduced at a very early
age. These data have been considered unsuitable to determine
the anthropometrical status of breastfed children. For example
formula fed infants are known to have higher weights and are
at greater risk for obesity1.
Alternative to the NCHS references, many countries have developed
their own growth standards.
The WHO has been active now for a number of years in a multi-centred
study to develop international growth standards based on breastfed
infants. Developing international standards however is not an
easy task. Much discussion over the past few years has focused
on a number of issues: international versus national standards;
the analytical methods to be used and how the growth curves are
to be presented -- i.e. as median, as centiles or as standard
deviations; research design is also under discussion -- should
the studies be cross-sectional or longitudinal, and the important
question of how to define exclusive breastfeeding.
Preliminary results of the WHO multi-centred study as part
of the preparatory work to set protocols to develop growth charts
have now been published2.
The seven country report -- Australia, Chile, China, Guatemala,
India, Nigeria, Sweden -- combines biweekly weights and length
measurements of 120 infants per site. Infants were selected with
mothers who were literate, had normal nutritional status and
who intended to breastfeed for at least 6 months. The statistical
method referred to as "multi-level modelling" was used
to account for individual and site specific effects on growth.
Interestingly, no site met the requirement for exclusive breastfeeding
(median durations of exclusive breastfeeding were 2 months or
less) for the required minimum of 4 months, despite the fact
that in three sites complementary feeding was started after this
age. Due to the low level of conformity to the breastfeeding
criteria, all babies were included in the results who were breastfed
to 12 months of age or longer, with adjustment for differences
according to breastfeeding practised (exclusive, predominant
or partial).
For those watching the results of growth patterns of exclusively
breastfed infants, this study raises the prospect that growth
faltering observed during the 5th and 6th
months may be related to the lack of exclusive breastfeeding
for the recommended period.
References:
1. von Kries, R. et
al. Breastfeeding and obesity: a cross sectional study. BMJ
319:147-150, 1999 BACK
2. WHO Working Group on
the Growth Reference Protocol and WHO Task Force on Methods for
the Natural Regulation of Fertility. Growth patterns of breastfed
infants in seven countries. Acta Pediatr 89:215-222, 2000
BACK |
