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Indian Pediatr 2011;48:
851-852 |
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Timing of Growth Faltering: A Critical Window
for Healthy Growth |
Mercedes de Onis
Growth Assessment and Surveillance Unit, Department of
Nutrition, World Health Organization, 20 Avenue Appia, 1211 Geneva 27,
Switzerland. [email protected]
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C hild undernutrition remains one of the main public
health challenges of the 21st century. Recent estimates suggest that
stunting, wasting, and intrauterine growth restriction are responsible for
2.2 million deaths and 21% of disability-adjusted life-years lost among
children under 5 [1]. Undernutrition also has long-term consequences,
which include short adult stature, reduced intellectual development and
economic productivity, and low offspring birth weight [2].
The Indian study published in this issue of Indian
Pediatrics [3] examines the timing of growth faltering in under-5
children in India using the WHO Child Growth Standards. Based on national
representative data, the authors conclude that about half (44% to 55%
depending on the survey year) of growth faltering was already present at
birth and that much of the growth faltering in early life in India can be
attributed to faltering in height-for-age (i.e. stunting). These results,
which are consistent with a recent analysis of child growth patterns
worldwide [4], confirm the importance of the first two years of life as a
critical window within which linear growth is most sensitive to
environmentally modifiable factors. The WHO Child Growth Standards, with
their robust methodology, provide an improved description of physiological
growth, showing that intrauterine growth retardation is a greater problem
than previously believed [3,4]. These findings highlight the need for
prenatal and early life interventions (in the -9 to +24 months window
of opportunity) to avert the growth failure that occurs during this
sensitive period.
Promoting healthy growth during gestation calls for
interventions to improve and safeguard maternal health and nutrition as a
means to preventing intrauterine growth restriction. Once born,
nutrition-dependent growth in the baby’s first two years hinges upon two
pillars; breastfeeding and complementary feeding. There is a large body of
scientific literature on what constitutes appropriate infant and young
child feeding, from exclusive breastfeeding during the first 6 months [5]
to guiding principles on complementary feeding [6]. More importantly,
there is ample evidence that appropriate infant feeding practices result
in better growth for infants and young children in poor environments.
Since growth faltering patterns are clearly different
for height-for-age and weight-for-age Z-scores, the new analyses [3,4]
also highlight the importance of monitoring length/height in addition to
weight throughout infancy and childhood. Despite its limited use, growth
velocity has considerable potential for early identification of abnormal
growth and treatment responses. Apart from the inherent complexities of
interpreting growth velocity, the dearth of reliable reference values has
been a major impediment to gaining a better understanding of how to use
growth velocities in ways that are helpful to clinicians [7]. WHO recently
published standards for growth velocity (based on length, weight and head
circumference) for variable intervals between birth and 24 months that
fill this gap by providing a biologically robust tool reflecting
age-specific changes in the rate of growth [7]. Identifying critical
velocity pattern thresholds to screen for faltering linear growth could
potentially allow early identification of children in the process of
faltering, thereby making interventions more timely and effective.
The problem of stunting has early beginnings and
long-term consequences. It is both a direct cause of short adult stature
and sub-optimal function later in life, and a key marker of the underlying
processes in early life that lead to poor growth and other adverse health
outcomes. However, stunting often goes unrecognized, especially in
communities where short stature is so common that it seems normal. Even
among health workers, stunting generally does not receive the same
attention as underweight or wasting (low weight-for-height), especially if
height is not routinely measured as part of community health programs.
Thus, in India, as elsewhere, early identification of linear growth
faltering and an understanding of its causal role and prevention are
essential for improving the effectiveness of public health programs in
preventing undernutrition.
References
1. Black RE, Allen LH, Bhutta ZA, Caulfield LE, de Onis
M, Ezzati M, et al. Maternal and child undernutrition: global and
regional exposure and health consequencies. Lancet. 2008;371:243-60.
2. Victora CG, Adair L, Fall C, Hallal PC, Martorell R,
Richter L, et al. Maternal and Child undernutrition: consequences
for adult health and human capital. Lancet. 2008; 371:340-57.
3. Mamidi RS, Shidhaye P, Radhakrishna KV, Babu JJ,
Reddy PS. Pattern of growth faltering and recovery in under-5 children in
India using WHO Growth Standards – A study on first and third National
Family Health Survey. India Pediatr. 2011;48:855-60.
4. Victora CG, de Onis M, Hallal PC, Blossner M,
Shrimpton R. Worldwide timing of growth faltering: revisiting implications
for interventions. Pediatrics. 2010;125:3473-80.
5. WHO. The optimal duration of exclusive
breastfeeding. Report of an Expert Consultation. Geneva: World Health
Organization, 2002.
6. PAHO/WHO. Guiding Principles for Complementary
Feeding of the Breastfed Child. Washington DC: Pan American Health
Organization, 2003.
7. de Onis M, Siyam A, Borghi E, Onyango AW, Piwoz E,
Garza C. Comparison of the World Health Organization growth velocity
standards with existing US reference data. Pediatrics 2011; 128:e18-26.
Epub 2011 Jun 27.
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