Contents - Previous - Next. Introduction 2. The timing of stunting 3. Age at menarche 4. Continued residence in the environment that gave rise to stunting 5. Continued residence in the same environment with improvements in nutrition 6. Relocation from the environment that gave rise to stunting 7. Discussion and conclusions References. The growth literature from developing countries is reviewed to assess the extent to which stunting, a phenomenon of early childhood, can be reversed in later childhood and adolescence.
The potential for catch-up growth increases as maturation is delayed and the growth period is prolonged. However, maturational delays in developing countries are usually less than two years, only enough to compensate for a small fraction of the growth retardation of early childhood. Follow-up studies find that subjects who remain in the setting in which they became stunted experience little or no catch-up in growth later in life.
Improvements in living conditions, as through food supplementation or through adoption, trigger catch-up growth but do so more effectively in the very young. One study cautions that in older adopted subjects, accelerated growth may accelerate maturation, shorten the growth period and lead to short adult stature. Some of these functional correlates, such as poor school performance, are not direct outcomes of growth failure, but instead reflect shared causes, whereas others, such as reduced lean body mass in the adult, undoubtedly are.
Are stunting and the adverse consequences it marks subject to partial or total recuperation in children who survive the turbulent first few years of life? This is a question of great scientific and policy importance. It is also a very broad question, and here only the issue of the reversibility of stunting per se will be addressed. A more comprehensive approach would also assess how reversing stunting affects its functional correlates. Tanner has written optimistically about the possibilities for reversing stunting.
He states: "Deflect the child from its natural growth trajectory by acute malnutrition or a sudden lack of hormone, and a restoring force develops, so that as soon as the missing food or the absent hormone is supplied again, the child hastens to catch up towards its original growth curve". It is clear that catch-up growth can occur under specific conditions.
What is less clear, however, is the degree to which catch-up growth can compensate for previous losses and whether catch-up growth can occur under a variety of conditions. Is the severity of growth failure an important predictor of the potential for catch-up growth? Does the timing of the growth retardation matter? For example, is it possible to recuperate growth retardation incurred in early childhood during the periods of middle childhood or adolescence?
Is the degree to which maturation is delayed, and thus the extent to which the duration of the growth period can be prolonged, a key element in determining the potential for catch-up growth?
The main purpose of this paper is: 1 to assess the degree to which the severe, linear growth failure that commonly occurs in early childhood can be redressed through catch-up growth; and 2 to identify the epidemiological factors or ecological settings which predict the degree of catch-up growth. This is an exemplary review which focuses on epidemiological data from developing countries.
Follow-up studies are examined in greater detail, in particular, studies that measured the same subjects in early childhood and later in adolescence or adulthood. Three unique settings are examined: 1 continued residence in the environment that gave rise to stunting; 2 continued residence in the same environment but with improvements in nutrition; and 3 relocation to an improved environment.
This review is not exhaustive on the subject of catch-up growth. Important omissions are studies of the growth response following treatment of such illnesses as celiac disease or hormonal deficiencies e. Though this omitted literature is vast, many reports deal only with selected cases, and statistical descriptions of defined populations are rare.
This is likely to lead to a bias towards the publication of cases with spectacular or more complete catch-up growth than commonly is the case. In commenting on this literature, Tanner observed that the potential for catch-up diminishes as a function of the severity, duration and timing i.
However, there may be a limitation imposed on an individual's maximum height by genetic imprinting in very early development. The data from US slaves and cases of hormonal replacement, where treatment was initiated after age 18, each show that, if the circumstances of children in the Third World change, almost complete reversal of stunting is possible.
The children can reach their own height potentials. Total reversal to affluent societal norms would probably require cross-generational catch-up. The most obvious reason why catch-up is not seen regularly is that an appropriate diet is not available over a sufficient period of time.
Amidst this buzz, IFPRI researchers Jef Leroy , Marie Ruel , and their co-authors decided to re-analyze data used in some of those studies to examine the validity of the surprising new claims. The main difference between previous studies which cited catch-up growth and the recent IFPRI research lies in the measurement.
This measure works for cross-country comparisons or to compare the nutritional status of different groups of children at different points in time. However, according to Leroy and his colleagues, HAZ is an incorrect measure for tracking changes in undernutrition as children age. HAZ is constructed using standard deviations from cross-sectional data, making it an inappropriate measure to evaluate changes in height as children grow. To prevent stunting, there are potential benefits to extending the coverage of early child development programmes to older children.
For example, Cuna Mas in Peru, which aims to improve development for children living in poverty, could be extended from children younger than three to children younger than six-years-old. It needs to be sustained throughout childhood and target the most stunted and undernourished children so they have a decent chance to recover. Andreas Georgiadis is a senior researcher at Young Lives.
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