The worldwide magnitude of protein-energy malnutrition: an overview from the WHO Global Database on Child Growth M. de Onis(1), C. Monteiro(2), J. Akr?#130;(3) and G. Clugston(4) (Click here for Microsoft Word version of this document)
1. Scientist, Nutrition unit, World Health Organization, 1211 Geneva 27, Switzerland. Request for reprints should be sent to this author.
2. Professor, School of Public Health: University of Sao Paulo, Brazil. Formerly: Consultant, Nutrition unit, World Health Organization, Geneva Switzerland.
3. Technical Officer, Nutrition unit, World Health Organization, Geneva, Switzerland.
4. Chief, Nutrition unit, World Health Organization, Geneva, Switzerland.
Using the WHO Global Database on Child Growth, which covers 87% of the total population of under-5-year olds in developing countries, we describe the worldwide distribution of protein-energy malnutrition, based on nationally representative cross-sectional data gathered between 1980 and 1992 in 79 developing countries in Africa, Asia, Latin America, and Oceania. The findings confirm that more than a third of the world鈥檚 children are affected. For all the indicators (wasting, stunting, and underweight) the most favourable situation low or moderate prevalences occurs in Latin America; in Asia most countries have high or very high prevalences; and in Africa a combination; of both these circumstances is found. A total 80% of the children affected live in Asia mainly in southern Asia 15% in Africa, and 5% in Latin America. Approximately, 43% of children (230 million) in developing countries are stunted. Efforts to accelerate significantly economic development will be unsuccessful until optimal child growth and development are ensured for the majority.
Growth assessment is the single measurement that best defines the health and nutritional status of children, because disturbances in health and nutrition, regardless of their etiology, invariably affect child growth. Health and nutrition problems during childhood are the result of a wide range of factors, most of which particularly in underprivileged populations relate to unsatisfactory food intake or severe and repeated infections, or a combination of the two. These conditions, in turn, are closely linked to the general standard of living and whether a population is able to meet its basic needs such as food, housing, and health care. Growth assessment thus serves as a means for evaluating the health and nutritional status of children, just as it also provides an indirect measurement of the quality of life of an entire population.
Of the various anthropometric indices that can be used to assess child growth status, the following provide a comprehensive description: height-for-age portrays performance in terms of linear growth, and essentially measures long-term growth faltering; weight-for-height reflects body proportion, or the harmony of growth, and is particularly sensitive to acute growth disturbances; and weight-for-age represents a convenient synthesis of both linear growth and body proportion (1).
WHO鈥檚 previous attempt to provide a global overview of the magnitude of protein-energy malnutrition appeared in 1983 (2). The present article expands and updates this analysis in the light of new data available from nutrition surveys in many more countries. Its immediate purpose is to contribute, as recently called for by the FAO/WHO International Conference on Nutrition [Food and Agriculture Organization of the United Nations/World Health Organization. International Conference on Nutrition, World Declaration and Plan of Action for Nutrition, Rome, December 1992. Unpublished WHO/FAO document ICN/92/2], to the availability of relevant and accurate information that can be helpful in monitoring trends, determining priorities, and evaluating the effectiveness of intervention programmes.
Nutrition is a basic human need that remains unmet for vast numbers of children, who are thus unable to achieve their full genetic developmental potential. The ultimate goal of this article is therefore to increase awareness of the magnitude of all forms of malnutrition as a critical first step to mobilizing the human and financial resources required to overcome the problem.
Cross-sectional data on the prevalences of wasting (low weight-for-height), stunting (low height-for-age) and underweight (low weight-for-age) were obtained from the WHO Global Database on Child Growth [WHO Global Database on Child Growth. Updates are available on request from: Nutrition Unit, World Health Organization, 1211 Geneva 27, Switzerland], which was initiated in 1986 to compile, systematize, and disseminate widely the results of anthropometric surveys performed in both developing and developed countries. The specific objectives of the database are to describe the worldwide distribution of child growth failure, permit intercountry and interregional comparisons, and facilitate the monitoring of global, regional and national trends. The existence of the database and its continual updating should stimulate new anthropometric surveys, particularly in those countries and regions thus far scarcely investigated.
The standardized presentation of results in the database is as follows:
systematic use of the NCHS/WHO international reference population (3);
display of growth retardation prevalences for under-5-year-olds, as measured by the proportion of weight-for-age, height-for-age and weight-for-height below -2 and -3 standard deviations (SDs) (z-scores);
display of the prevalence of overweight, as measured by the proportion of children with weight-for-height above +2 z-scores;
display of z-score means and SDs for the three indices; and
stratification of the results according to age, sex, region, and rural/urban strata.
The criteria for entering surveys in the database are outlined below.
A clearly defined population-base sampling frame; permitting inferences to be drawn about an entire population.
A probabilistic sampling procedure involving at least 400 children (allowing for an estimation of prevalences with a random error of less than or equal to 5% at a confidence level of 95%).
Use of appropriate equipment and standard measurement techniques (3).
Presentation of results as z-scores in relation to the NCHS/WHO reference population or availability of raw data, permitting a standardized analysis to be made by WHO.
The present analysis is restricted to nationally representative surveys from developing countries in Africa, Asia, Latin America, and Oceania that were carried out between 1980 and 1992. Countries are grouped according to the United Nations classification (4), which divides the world into seven major areas and 22 regions; estimates of the under-5-year-old populations in 1990 for the countries concerned were obtained from the United Nations Population Division (4).
Regional prevalences for the indices were estimated for each geographical area by weighting the available national prevalences according to the population of under-5-year-olds in each country in 1990. The numbers of underweight, stunted, and wasted children in each area were obtained by applying prevalence estimates to the total population of under-5-year-olds in 1990. Global prevalences in developing countries were calculated by adding the estimates for the number of affected children in each area and then dividing the sum obtained by the 1990 under-5-year-old population of all developing countries. Estimates concerned with underweight, stunting and wasting were obtained only for those regions where the proportion of children covered by national surveys was at least 70%, and in most cases over 80%.
Coverage attained by the database
Coverage in Africa. Anthropometric surveys carried out before 1980 are included in the database for 17 out of 52 African countries. The coverage for surveys carried out since 1980 is substantially better (40 countries), most of which are national surveys. Regional or national surveys in Africa are lacking from Comoros, Mozambique and Somalia (in the east), Gambia and Guinea (in the west), Angola, Central African Republic and Chad (in the middle), and Libya (in the north).
Coverage in Asia. Developing countries in Asia are also scarcely represented in the child growth database before 1980 (8 out of 37 countries). Coverage improves for later surveys (24 countries), and mostly is based on national data, including surveys carried out in populous countries such as Bangladesh, China, India, Indonesia, and Pakistan. Countries still not represented in the database are mostly in western Asia (Bahrain, Cyprus, Lebanon, Qatar, Syria, Turkey, and United Arab Emirates), but also include Hong Kong and Republic of Korea (in east Asia), and Brunei and Cambodia (in south-eastern Asia).
Coverage in Latin America. Nearly half of the countries in Latin America (17 out of 36) are represented in the child-growth database before 1980. Coverage improves for more recent surveys (25 countries), most of which are based on the results of national surveys. Those countries still not included in the database are mostly in the Caribbean (Bahamas, British Virgin Islands, Grenada, Montserrat, Saint Kitts and Nevis, and Turks and Caicos Islands), but include also Argentina and Suriname in South America.
Coverage in Oceania. Coverage of developing countries in Oceania is restricted not only prior to 1980 (2 out of 13 countries) but also has failed to improve subsequently (only 3 countries based on national surveys). The following countries are still not included in the database: Fiji and New Caledonia (in Melanesia); Federal States of Micronesia, Marshall Islands, and Palau (in Micronesia); and Cook Islands, Samoa, Tonga and Tuvalu (in Polynesia).
Table 1 shows the population coverage attained by the child-growth database relative to national surveys performed since 1980. Taken as a whole, these surveys cover a population of 468 million children, or 87% of the estimated total number of under-5-year-olds in developing countries in 1990. The coverage is higher almost 90% or more in northern, eastern and western Africa, the whole of Asia, in eastern, southern and south-eastern Asia, and in Latin America. Coverage is around 70% throughout Africa and throughout Oceania, including Melanesia (the most populous region in Oceania). Middle and southern Africa, western Asia, and Micronesia are not adequately represented by national surveys, the coverage attained in these regions being, respectively, only 18.1%, 10.4%, 34.6%, and 20.0% of the total population of under-5-year-olds. Polynesia is not yet represented in the database.
Table 1: Population coverage in the WHO Global Database on Child Growth,with respect to national surveys, 1980-92(a) Total Population No. of population surveyed Coverage countries (millions) (millions) (%) surveyed (total)Africa 115.52 89.44 77.4 (34/52)Northern Africa 21.58 20.75 96.2 (5/6)Eastern Africa 37.19 32.84 88.3 (13/16)Western Africa 37.24 32.79 88.0 (10/16)Middle Africa 13.28 2.41 18.1 (3/9)Southern Africa 6.23 0.65 10.4 (3/5)Asia 366.86 326.81 89.1 (19/37)Eastern Asia 122.27 116.14 95.0 (2/5)Western Asia 19.62 6.80 34.6 (5/13)South-eastern Asia 57.66 53.45 92.7 (6/10)Southern Asia 167.31 150.42 89.9 (6/9)Latin America 54.63 51.20 93.7 (23/36)Caribbean 3.39 3.31 97.6 (6/16)Central America 16.07 16.07 100.0 (7/8)South America 35.17 31.82 90.5 (10/12)Oceania 0.86 0.57 66.3 (3/13)Melanesia 0.73 0.56 76.7 (2/5)Micronesia 0.05 0.01 20.0 (1/4)Polynesia 0.08 0.00 0.0 (0/4)All developing countries 537.87 468.02 87.0 (79/138)(a) Under-5-year-old population estimates refer to 1990 according toUnited Nations Population Division. See ref. (4).Overview of national surveys
The results of national surveys carried out between 1980 and 1992 in 79 developing countries in Africa, Asia and Latin America are summarized in Table 2 and in Fig. 1-3. Most surveys refer to a national random sample of children aged up to 59 months.
The worldwide distribution of underweight. Fig. 1 shows the distribution of developing countries according to the prevalence of underweight children (weight-for-age below -2 SD from the reference median value). Prevalences are grouped into four categories (less than 10%, 10-19%, and 30% or more), corresponding approximately to the quartile distribution observed in the 79 countries surveyed. These categories of underweight prevalences are referred to as (relatively) low, moderate, high, and very high.
Most developing countries in Latin America have low or moderate prevalences of underweight children, while most countries in Asia have high or very high prevalences. In Africa, however, both moderate and high prevalences are found.
In most of the 23 countries surveyed in Latin America the prevalence of underweight is low or moderate. The exceptions are Honduras (high prevalence) and Guatemala (very high) in Central America; Guyana (high), in South America; and Haiti (very high), in the Caribbean.
Table 2: Prevalence(a) of underweight, stunting and wasting among under-5-year-olds in 79 developing countries, based on national surveys, 1980-92 Survey Sample % under- performed size weight % stunting % wastingAlgeria 1992 - 9.2 18.1 5.5Bangladesh 1989-90 1,914 65.8 64.6 15.5Barbados 1981 533 5.3 7.4 3.8Bhutan (c) 1986-88 3,273 37.9 56.1 4.1Bolivia (b) 1989 2,537 13.3 38.3 1.6Brazil 1989 7,314 7.0 15.4 2.0Burundi (b) 1987 1,930 38.3 48.1 5.6Cameroon 1991 2,357 13.6 24.4 3.0Cape Verde 1983 14,767 19.0 14.9 4.8Chile (c) 1986 - 2.5 9.6 0.5China 1987 76,130 21.3 32.1 3.6Colombia 1986-89 1,973 10.1 16.6 2.9Congo 1987 2,429 23.5 27.1 5.4Costa Rica 1982 1,870 6.0 7.8 2.0C"te d鈥橧voire 1986 1,947 12.4 17.2 8.6Cuba (d,e) 1987 - - - 0.5Djibouti 1989 3,750 22.9 22.2 10.7Dominican Republic 1991 2,884 10.4 19.4 1.1Ecuador 1986 7,798 16.5 34.0 1.7Egypt 1990 - 10.4 30.0 3.5El Salvador 1988 2,039 15.2 29.9 -Ethiopia (f,g) 1992 20,230 47.7 64.2 8.0Ghana 1987-88 2,494 27.1 30.5 7.3Guatemala (b) 1987 2,230 33.5 57.9 1.4Guyana 1981 532 22.1 20.7 8.5Haiti (h) 1990 967 33.9 40.6 4.2Honduras 1987 3,338 20.6 33.9 1.9India (i) 1988-90 13,548 63.9 62.1 19.2Indonesia 1987 28,169 39.9 - -Iraq 1991 2,565 11.9 21.8 3.4Jamaica 1989 860 7.2 8.7 3.4Jordan 1990 6,601 6.4 19.3 2.8Kenya (g) 1987 - 14.3 32.2 4.5Kiribati 1985 2,941 12.9 28.3 10.8Kuwait 1983-84 2,272 6.4 11.3 2.7Laos 1984 6,055 36.7 40.1 10.5Lesotho (j) 1981 5,467 15.6 26.1 4.5Madagascar (k) 1983-84 1,762 32.8 33.5 11.8Malawi 1992 3,236 27.2 48.6 5.4Maldives 1983 1,485 - - 6.3Mali (b) 1987 925 31.0 24.4 11.0Mauritania 1990-91 4,807 47.6 56.9 15.8Mauritius 1985 2,430 23.9 21.5 16.2Mexico 1988 7,426 16.3 27.0 5.5Morocco (b) 1987 3,292 15.7 25.5 3.7Mongolia (l) 1992 1,679 12.3 26.4 1.7Myanmar (b) 1983-85 6,255 38.0 49.7 11.0Namibia 1992 2,430 26.2 28.4 8.6Nicaragua 1980-82 1,611 10.5 21.8 0.6Niger 1992 3,848 36.2 32.3 15.8Nigeria 1990 5,565 35.7 43.1 9.1Oman (d) 1991 764 24.3 20.7 7.3Pakistan 1990-91 4,037 40.4 50.0 9.2Panama 1980 3,314 15.7 22.0 6.4Papua New Guinea (g) 1982-83 27,464 29.9 43.2 5.5Paraguay 1990 3,389 3.7 16.6 0.3Peru 1991-92 7,035 10.8 36.5 1.4Philippines 1987 2,250 32.9 38.6 4.5Rwanda (g) 1991-92 1,939 28.6 52.2 5.2Sao Tome and Principe 1986 2,155 17.0 26.0 5.0Senegal (f) 1991-92 - 21.6 29.1 5.5Seychelles 1987-88 836 5.7 5.1 2.0Sierra Leone 1990 4,595 28.7 34.7 8.5Sri Lanka (b) 1987 1,994 38.1 27.5 12.9Sudan (m) 1987 15,534 - - 12.5Swaziland (g) 1983-84 4,133 9.7 30.3 0.9Tanzania 1991-92 6,097 28.8 42.6 6.0Thailand (b) 1987 1,856 25.8 22.4 5.7Togo (b) 1988 1,396 24.4 29.6 5.3Trinidad and Tobago (b) 1987 842 6.9 5.0 3.8Tunisia (b) 1988 2,023 10.4 18.2 3.1Uganda 1988-89 3,789 23.3 44.5 1.9Uruguay (c,j) 1987 3,471 7.4 15.9 -Vanuatu 1983 1,194 19.7 19.1 -Venezuela 1981-82 6,745 10.2 6.4 1.3Viet Nam 1987-89 7,044 45.0 56.5 9.4Yemen 1991-1992 - 30.0 44.1 12.7Zambia 1992 4,899 25.1 39.6 5.1Zimbabwe 1988 2,485 11.5 29.0 1.3(a) % Below -2 SD of the WHO/NCHS reference population. Source: WHO Global Child Growth Database (see note under Methods section).(b) under 3 years of age (Bolivia, Burundi, Guatemala, Mali, Morocco, Myanmar, Sri Lanka, Thailand, Togo, Trinidad and Tobago, and Tunisia). (c) 0-72 months (Bhutan, Chile, and Uruguay). (d) 12-59 months (Cuba and Oman). (e) less than 3rd centile (Cuba). (f) 6-59 months (Ethiopia and Senegal). (g) National rural survey covering over 80% of the total under-5-year-old population (Ethiopia, Kenya, Papua New Guinea, Rwanda, and Swaziland).(h) Conducted in the five most populous of the nine departments (Haiti).(i) Survey of rural population of eight states (India).(j) National surveillance system (Lesotho and Uruguay(k) 0-23 months (Madagascar).(l) 0-48 months (Mongolia).(m) Northern Sudan (Sudan).In Africa, a greater variation seems to occur among regions. The situation in northern Africa (represented in the database by Algeria, Egypt, Morocco, and Tunisia) is similar to that in Latin America, with a low or moderate prevalence of underweight. In western Africa, countries are mostly affected by high and very high prevalences, as is the case in eastern Africa. The only three surveys available for middle Africa make it difficult to generalize about the frequency of underweight there (the prevalence is moderate in Cameroon and S o Tome and Principe, and high in Congo). In southern Africa, the lack of national data for the two most populous countries, Botswana and South Africa, makes it difficult to define the pattern of underweight prevalences in the region (the prevalence is high in Namibia, moderate in Lesotho, and low in Swaziland).
In all the countries surveyed in southern Asia (Bangladesh, Bhutan, India, Pakistan, and Sri Lanka) the prevalence of underweight is very high. With the exception of Thailand, this applies also to all the countries surveyed in south-eastern Asia (Indonesia, Laos, Myanmar, Philippines, and Vietnam). In Eastern Asia, China has a high prevalence of underweight and Mongolia a moderate prevalence. Paucity of surveys and contrasting results (low prevalence in Jordan and Kuwait, moderate in Iraq, high in Oman, and very high in Yemen) make it difficult to discern a prevalence pattern in western Asia.
The worldwide distribution of stunting and wasting. Fig. 2 and 3 show the distribution of developing countries according to their prevalence of stunted and wasted children (respectively, height-for-age and weight-for-height below -2 SD of the values for the reference median). As in the case of underweight, the prevalences of stunting are grouped into four categories corresponding to the quartiles of observed values in the 79 countries surveyed: under 20%, 20-29%, 30-39%, and 40% and over (referred to here as low, moderate, high, and very high prevalences of stunting, resp.). The prevalences of wasting were originally grouped according to quartiles, producing four categories: under 2%, 2-3%, 4-7%, and 8% and over; however, since both the two first categories are similar to expected values for the reference population (2.3%), they were pooled under one category (under 4%), referred to as low prevalence of wasting. The two remaining categories (4-7% and 8% and over) are referred to as high and very high prevalences of wasting.
In broad terms, the differences between geographical areas as regards stunting and wasting resemble the situation for the distribution of underweight: high prevalences in Asia, low prevalences in Latin America, and a combination of both in Africa. On closer inspection, however, the situation in Latin America for stunting tends towards that in Africa, while for wasting the prevalences in Africa tend towards those in Asia.
The most favourable situation a low/moderate prevalence of stunting and a low prevalence of wasting is commonly found in countries in Latin America, while the opposite high/very high prevalence of both stunting and wasting is commonly found in countries in Asia. A combination of high/very high prevalence of wasting and a low/moderate prevalence of stunting indicating a predominance of acute over chronic malnutrition though relatively rare in Latin America (Guyana, Mexico, and Panama) and Asia (Sri Lanka and Thailand), is quite common in Africa (10 countries, five of them in western Africa). The opposite pattern high or very high prevalence of stunting combined with a low prevalence of wasting which suggests a predominance of chronic over acute under nutrition, occurs in some countries in Latin America (Bolivia, Ecuador, Guatemala, Honduras, and Peru), in some countries in Africa (Egypt, Swaziland, and Uganda), and in the largest country in Asia (China).
Global and regional estimates
Table 3 shows the global estimates for the prevalences of underweight, stunting, and wasting in developing countries, as well as the estimated absolute number of children affected by growth retardation. Available data for these prevalences are based on surveys covering 94% of the total population of under-5-year-olds in Latin America, 90% in Asia, 77% in Africa, and 66% in Oceania (see Table 1).
Table 3: Global estimates for the prevalence(a) and number of underweight,stunted, and wasted children in developing countries % underweight % stunted % wastedAfrica 27.4 (31.6)(b) 38.6 (44.6) 7.2 (8.3)Asia 42.0 (154.1) 47.1 (172.8) 10.8 (39.6)Latin America 11.9 (6.5) 22.2 (12.1) 2.7 (1.5)Oceania 29.1 (0.3) 41.9 (0.4) 5.6 (0.1)All developing countries 35.8 (192.5) 42.7 (229.9) 9.2 (49.5)(a) % Below -2 SD of WHO/NCHS reference value.(b) Figures in parentheses are millions of children.According to the estimates shown in Table 3, the risk of being underweight is 1.5 times higher in Asia than in Africa, and 2.3 times higher in Africa than in Latin America. Similar differences exist for stunting and wasting, although again it should be noted that the levels of stunting in Latin America tend towards those in Africa, while those for wasting in Africa tend towards the levels in Asia. The number of under-5-year-olds in each geographical area 54 million in Latin America, 115 million in Africa, and 366 million in Asia has the effect of making the regional distribution even more unequal. Irrespective of the indicator used, nearly 80% of affected children live in Asia, 15% in Africa, and only about 5% in Latin America. Oceania, despite its high prevalences of all three indicators, contribut, es very little to the absolute number of undernourished children, since there are fewer than 1 million under-5-year-olds in developing countries in this region.
Estimates of underweight, stunting, and wasting have also been obtained for the 10 regions that are reasonable well covered by national surveys. Except for estimates of stunting and wasting in south-eastern Asia, which are based on national surveys covering 53.3% of the total under-5-year-old population, all others are based on surveys covering at least 70% of the total population of under-5-year-olds. Based on these estimates, regions have been ranked in descending order according to both the prevalence (Table 4) and the absolute number of affected children (Table 5).
Table 4: Regional estimates for the prevalence(a) of underweight, stunted,and wasted children in developing countries, ranked in descending order % underweight % stunted % wastedSouthern Asia 60.5 Southern Asia 60.3 Southern Asia 17.3South-eastern Asia 37.8 Eastern Africa 47.0 Western Africa 9.5Western Africa 32.8 South-eastern Asia 43.2 South-eastern Asia 7.6Eastern Africa 31.0 Melanesia 42.2 Eastern Africa 6.0Melanesia 29.5 Western Africa 37.9 Northern Africa 5.8Eastern Asia 21.3 Eastern Asia 32.1 Melanesia 5.5Caribbean 19.4 Central America 29.8 Central America 4.6Central America 17.7 Caribbean 25.9 Eastern Asia 3.6Northern Africa 11.3 Northern Africa 25.4 Caribbean 2.2Southern America 8.4 Southern America 18.1 Southern America 1.9(a) % Below -2 SD of the WHO/NCHS reference value.The prevalences of underweight, stunted, and wasted children are far higher in southern Asia than in any other region. South-eastern Asia ranks second in the descending order of prevalences of underweight and third for wasting and stunting. Western Africa ranks second for wasting, third for underweight, and fifth for stunting. Eastern Africa ranks second for stunting and fourth for wasting and underweight. Melanesia ranks fourth for stunting, fifth for underweight, and sixth for wasting.
Eastern Asia (China and Mongolia) comes next in the descending order of prevalence of underweight and stunting, but ranks closer to the less-affected (Latin American) regions as far as wasting is concerned.
The lowest estimates for the prevalence of underweight, stunted, and wasted children are found in northern Africa and in the three regions of Latin America. The lowest prevalences of all three indicators occur in South America.
The ranking of regions according to the numbers of affected children reinforces the leading position of southern Asia half of all underweight, stunted, and wasted children in developing countries are located here. Eastern Asia ranks above African regions for these three indicators, and before south-eastern Asia where stunting and underweight are concerned. The Caribbean and Melanesia contribute the least in terms of absolute numbers of the world鈥檚 undernourished children.
Table 5: Regional estimates for the number of underweight, stunted and wasted children in developing countries, ranked by descending orderNo. underweight (millions) No. stunted (millions) No. wasted (millions)Southern Asia 101.2 Southern Asia 100.9 Southern Asia 28.9Eastern Asia 26.0 Eastern Asia 39.2 South-eastern Asia 4.4South-eastern Asia 21.8 South-eastern Asia 24.9 Eastern Asia 4.4Western Africa 12.2 Eastern Africa 17.5 Western Africa 3.5Eastern Africa 11.5 Western Africa 14.1 Eastern Africa 2.2Southern America 2.9 Southern America 6.4 Northern Africa 1.2Central America 2.8 Northern Africa 5.5 Central America 0.7Northern Africa 2.4 Central America 4.8 Southern America 0.7Caribbean 0.6 Caribbean 0.9 Caribbean 0.1Melanesia 0.2 Melanesia 0.3 Melanesia 0.0Discussion
The data we have presented here document a disturbing picture of undernutrition among preschool-age children in underprivileged populations. Our findings confirm the great magnitude of undernutrition which, more than any other disability, continues to hamper the physical growth and mental development of more than a third of the world鈥檚 children. Indeed, it is a major threat to their very survival.
The accumulated evidence in the WHO Global Database on Child Growth permits an accurate description of the magnitude and geographical distribution of protein-energy malnutrition. At present, the database covers 87% of the total population of under-5-year-olds (about 468 million children) living in developing countries in 1990, and thus allows calculation of reliable estimates on a regional basis. This global overview is a major improvement over WHO鈥檚 previous attempt, made a decade ago, which was based on heterogeneous data sets using different reference populations and cut-off points (2); also far fewer countries and nationally representative surveys on which to base conclusions were included.
Our review of 79 national surveys carried out between 1980 and 1992 in developing countries demonstrates that undernutrition is still very common among preschool-age children, resulting in small (stunted) rather than thin (wasted) children. Most countries in Asia have high or very high prevalences of underweight children, while in Latin America, most countries have low or moderate prevalences of such children. In Africa, there appears to be a greater variation among regions than in either Asia or Latin America. Thus, the situation in northern Africa is similar to that in Latin America, while in western and eastern Africa countries are mostly affected by high and very high prevalences of underweight.
The differences between regions in terms of stunting and wasting duplicate those observed for the distribution of underweight . The most favourable situation a low prevalence of both stunting and wasting is commonly found in Latin America, whereas the opposite is true in Asia. A combination of high wasting with low stunting, which indicates a predominance of acute over chronic malnutrition, is rare in Latin America and Asia but quite common in Africa, particularly western Africa. The opposite pattern, which suggests a predominance of chronic over acute malnutrition, occurs in China and in some countries in Latin America and Africa.
Our estimate for the global prevalence of underweight preschool-age children in developing countries (35.8%) is consistent with a recent value obtained using the same data but a different methodology (5). However, there have been no previous estimates of the prevalence and absolute numbers of stunted and wasted preschool-age children. Broadly speaking, the risk of being underweight is 1.5 times higher in Asia than in Africa, and 2.3 times higher in Africa than in Latin America. Similar differences exist for stunting and wasting. Differences in population size make the regional distribution even more unequal, with 80% of the affected children living in Asia mainly in southern Asia 15% in Africa, and only 5% in Latin America.
We estimate that 43% of under-5-year-olds in developing countries have low heights-for-age. Several studies have shown that stunting is associated with poor developmental attainment in young children (6, 7) and poor school achievement or intelligence levels in older children (8, 9). Furthermore, Matorell et al. recently provided the clearest demonstration that growth retardation in early childhood is associated with significant functional impairment in adult life (10). Children affected by marked growth retardation become adults with limited biological and intellectual abilities that diminish their working capacity. In women, stunting is a matter of great concern in terms of increased obstetric risks. Finally, stunted children frequently experience social disadvantages, which themselves may detrimentally affect their development (11).
Social equity, as reflected in international human rights law (12) [Convention on the Rights of the Child. New York, United Nations General assembly document A/RES/44/25, 5 December 1989], affirms the right of every child to adequate nutrition to ensure proper physical growth and mental development. In a world where there is enough food for everyone, but where inequitable access to it is the main problem, [Food and Agriculture Organization of the United Nations/World Health Organization. International Conference on Nutrition, World Declaration and Plan of Action for Nutrition, Rome, December 1992. Unpublished WHO/FAO document ICN/92/2]. [WHO Commission on Health and Environment: report of the Panel on Food and Agriculture. Unpublished document WHO/EHE/92.2.] it is intolerable that more than 200 million preschool-age children continue to suffer the consequences of undernutrition.
The causes of growth retardation are deeply rooted in poverty and lack of education. To continue to allow underprivileged environments to affect children鈥檚 development not only perpetuates the vicious cycle of poverty but also leads to an enormous waste of human potential. If the nutritional well-being of people is a precondition for the development of societies, it is all the more so where their most vulnerable members children are concerned. Governments will be unsuccessful in their efforts to accelerate economic development in any significant long-term sense until optimal child growth and development are ensured for the majority.