Commentary: Socioeconomic inequalities and child growth

Mercedes de Onis

Department of Nutrition for Health and Development, World Health Organization, CH-1211, Geneva 27, Switzerland. E-mail: deonism{at}who.ch

The article by John Pemberton ‘Malnutrition in England‘, which appeared in the University College Hospital Magazine in 1934,1 looked at the effects of poor nutrition on child health at a time when this was considered a major problem in Britain. The paper raised a key association that nowadays no one would refute, that of deprivation with poor nutrition and impaired child growth. Dr Pemberton based his observation on an analysis of the cost of providing the minimum diet, as recommended by the British Medical Association, for a typical family consisting of a husband and wife and three children, versus the statutory unemployment benefit for such a family. The comparison permitted Pemberton to conclude that they could buy at the least 48%, and at the most, 74% of the requisite amount of food to keep themselves healthy and able to work. The same results were seen for any size of family. A comparable investigation, arriving at similar conclusions, had been carried out 2 years earlier by Dr Crowden and colleagues from the London School of Hygiene and Tropical Medicine.2 Based on the two reports, in conjunction with the rates of unemployment benefits in place at the time, the author concluded that the majority of the unemployed and their families must be suffering from what he called ‘chronic under-nourishment’.

To illustrate the effect this situation has on the health status of the affected families, Pemberton used a then recent investigation of the health and nutritional status of preschool children in Newcastle. The study compared a sample of children from unemployed, low-paid working-class families with a control sample chosen from well-to-do professional families. The comparison yielded striking differences between the two groups in terms of attained linear growth, weight status, and indicators of anaemia and respiratory infections. The investigators concluded that the low standard of health in the sample of poor children was preventable, and due mainly to overcrowding and under-nourishment.

There are interesting parallels between the paradox referred to by Dr Pemberton—‘a world where large quantities of food are burnt annually at the same time that hundreds of people are under-fed’—and the situation in many parts of the world today. English children have come a long way since those early days and, today, the vast majority enjoys high levels of health and nutritional status. Indeed, concern is being raised about the opposite problem, i.e. overweight and obesity.3 A recent investigation reported that between 1989 and 1998, among 3–4 year old English children, there was a 60% increase in the prevalence of overweight and a 70% increase in the prevalence of obesity.4 However, this is not the case for millions of children worldwide. Child malnutrition remains a major public health problem in developing countries.5 In some countries rates of stunting—a process of failure to reach linear growth potential—are rising, while in many others they remain disturbingly high.6

The health and social consequences of the current high prevalences of child malnutrition are severe. It is now recognized that about 60% of childhood deaths occurring every year are attributable to malnutrition,7 and a recent global analysis demonstrates that childhood malnutrition is the leading cause of the global burden of disease.8,9 Children suffering from impaired growth tend to have more severe diarrhoeal episodes and are more susceptible to several infectious diseases such as malaria, pneumonia, or meningitis. Similarly, there is strong evidence that poor growth is associated with impaired cognitive development and a number of studies have demonstrated a relationship of growth status with school performance and intellectual achievement.10–12 Child stunting leads to significant reduction in adult size;12 one of the main consequences of small adult size resulting from stunting during childhood is reduced work capacity,13 which in turn has an impact on economic productivity. The implications of the long-lasting consequences of impaired child growth are enormous for the human and socioeconomic development of the affected populations.

The observation made by Pemberton of the direct link between social deprivation and poor nutritional status and ill health is today well-founded on empirical evidence. On a population basis, high levels of stunting are associated with poor socioeconomic conditions and increased risk of frequent and early exposure to adverse conditions such as illness and/or inappropriate feeding practices.14 Similarly, a decrease in the national stunting rate is usually indicative of improvements in overall socioeconomic conditions of a country.15 To illustrate this point, Figure 1Go presents the height-for-age z-score distribution, by quartiles of per capita family income, for a national sample of Brazilian children compared with the National Center for Health Statistics (NCHS)/WHO international growth reference distribution. As Figure 1Go shows, the entire Brazilian distribution shifted to the right in moving from the lowest to the highest income quartile distribution until it overlaps with that of the NCHS/WHO reference in the highest quartile of per capita income. Similarly, based on national-level data for four countries (Bolivia, Nepal, Pakistan, and Peru), Figure 2Go shows the association between height-for-age and maternal education. What is striking is the similarity in the pattern of the association and dose–response relationship; the rate of stunting declines as levels of education increase across the four countries. This intrinsic link between poverty indicators and anthropometric deficits has not only made child-growth assessment an excellent means for evaluating the health and nutritional status of children but also provided a measurement of the health inequalities faced by entire populations.17



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Figure 1 Height-for-age by quartiles of per capita income in a national sample of Brazilian preschool age children (Source: Ref. 16)

 


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Figure 2 Variation of height-for-age according to maternal educational level for four national samples of preschool age children (Source: Ref. 14)

 
Pemberton ends his paper by questioning the capacity of the medical profession to deal with the situation given the number of reports documenting increasing numbers of malnourished and infected children. In his view, the solution lies out of reach of the ‘Art of Medicine’ as the problem is rooted in the inability of families to meet their basic needs such as food, housing, and health care. However, the medical community can play an important role by raising public awareness of the problem, and by doing so, mobilize political commitment to make the legislative changes that will ensure that citizens receive welfare services that will allow them to cover their basic needs. Despite 70 years difference, there is some resemblance between the situation faced by Dr Pemberton and his colleagues in the 1930s and that faced by the scientific and health community today. Last year, nearly 11 million children died before they reached the age of 5 years. More than half of these children did so of diseases that could have been easily prevented or treated.8 Given these numbers and the fact that so many lives could be saved with the implementation of relatively simple measures, it is surprising that child health does not receive more attention. This year, and with similarities to the ‘Committee Against Malnutrition’ described in Pemberton’s paper, a working group formed by researchers in the area of child health will be established in Bellagio, Italy, assisted by The Lancet, to refocus the world’s attention on child health and make it an international health priority once again.18 The working group is expected to lay out what must be done to avoid millions of preventable deaths and improve child health in a meaningful way. The question will then be whether there is adequate political commitment at national and international levels to do what is necessary.


    Acknowledgments
 
I would like to thank Jim Akre for his editorial help in preparing this commentary.


    References
 Top
 References
 
1 Pemberton J. Malnutrition in England. University College Hospital Magazine 1934;Jul–Aug:153–59. (Reprinted Int J Epidemiol 2003; 32:493–95.)

2 Crowden GP et al. The minimum cost of physiologically adequate diets for working class families. Lancet 1932;i:899.

3 Ebbeling CB, Pawlak DB, Ludwig DS. Childhood obesity: public-health crisis, common sense cure. Lancet 2002;360:473–82.[CrossRef][ISI][Medline]

4 Bundred P, Kitchiner D, Buchan I. Prevalence of overweight and obese children between 1989 and 1998: population based series of cross sectional studies. BMJ 2001;322:326–28.[Abstract/Free Full Text]

5 de Onis M, Blössner M. WHO Global Database on Child Growth and Malnutrition. Doc WHO/NUT/97.4. Geneva: World Health Organization, 1997.

6 de Onis M, Frongillo EA, Blössner M. Is malnutrition declining? An analysis of changes in levels of child malnutrition since 1980. Bull World Health Organ 2000;78:1222–33.[ISI][Medline]

7 Fishman S, Caulfield LE, de Onis M, Blossner M, Mullany L, Black RE. Malnutrition and the global burden of disease: underweight. In: Comparative Quantification of Health Risks: The Global and Regional Burden of Disease due to 25 Selected Major Risk Factors. Cambridge: World Health Organization/Harvard University Press, 2003 (in press).

8 World Health Organization. The World Health Report 2002: Reducing Risks, Promoting Healthy Life. Geneva: WHO, 2002.

9 Ezzati M, Lopez AD, Rodgers A, Vander Hoorn S, Murray CJL, and the Comparative Risk Assessment Collaborating Group. Selected major risk factors and global and regional burden of disease. Lancet 2002;360:1347–60.[CrossRef][ISI][Medline]

10 Pollitt E, Gorman KS, Engle PL, Martorell R, Rivera J. Early supplementary feeding and cognition. Monogr Soc Res Child Dev 1993;58:1–99.[ISI]

11 Pan American Health Organization. Nutrition, Health and Child Development. Scientific Publication No. 566. Washington, DC: PAHO, 1998.

12 Martorell R, Rivera J, Kaplowitz H, Pollitt E. Long-term consequences of growth retardation during early childhood. In: Hernandez M, Argente J (eds). Human Growth: Basic and Clinical Aspects. Amsterdam: Elsevier Science Publishers, 1992, pp. 143–49.

13 Spurr GB, Barac-Nieto M, Maksud MG: Productivity and maximal oxygen consumption in sugar cane cutters. Am J Clin Nutr 1977;30:316–21.[Abstract]

14 de Onis M. Child growth and development. In: Semba RD, Bloem MW (eds). Nutrition and Health in Developing Countries. Totowa, NJ: Humana Press, 2001, pp. 71–91.

15 Frongillo EA Jr, de Onis M, Hanson KMP. Socioeconomic and demographic factors are associated with worldwide patterns of stunting and wasting of children. J Nutr 1997;127:2302–09.[Abstract/Free Full Text]

16 de Onis M, Yip R. The WHO growth chart: historical considerations and current scientific issues. Bibl Nutr Dieta 1996;53:74–89.[Medline]

17 World Health Organization. Physical Status: The Use and Interpretation of Anthropometry. Technical Report Series No. 854. WHO: Geneva, 1995.

18 Anonymous. The world’s forgotten children. Lancet 2003;361:1.[CrossRef][ISI][Medline]





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