The worldwide magnitude of protein-energy malnutrition: an overview from the WHO Global Database on Child Growth.

Research I Recherche The worldwide magnitude of protein-energy malnutrition: an overview from the WHO Global Database on Child Growth M. de Onfs,1 C. Monteiro,2 J. Akre,3 & G. Clugston4 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 devel- oping countries in Africa, Asia, Latin America, and Oceania. The findings confirm that more than a third of the world's 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. Introduction Growth assessment is the single measurement that best defines the health and nutritional status of chil- dren, because disturbances in health and nutrition, regardless of their etiology, invariably affect child growth. Health and nutrition problems during child- hood are the result of a wide range of factors, most of which - particularly in underprivileged popula- tions - 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 I Scientist, Nutrition unit, World Health Organization, 1211 Geneva 27, Switzerland. Requests 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 Organ- ization, Geneva, Switzerland. 3 Technical Officer, Nutrition unit, World Health Organization, Geneva, Switzerland. 4 Chief, Nutrition unit, World Health Organization, Geneva, Swit- zerland. Reprint No. 5432 of children, just as it also provides an indirect measurement of the quality of life of an entire popu- lation. 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 repre- sents a convenient synthesis of both linear growth and body proportion (1). WHO's previous attempt to provide a global overview of the magnitude of protein-energy malnu- trition 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,a to the availability of rel- a 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. Bulletin of the World Health Organization, 71 (6): 703-712 (1993) © World Health Organization 1993 703 M. de Onis et al. evant and accurate information that can be helpful in monitoring trends, determining priorities, and evalu- ating 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 there- fore to increase awareness of the magnitude of all forms of malnutrition as a critical first step to mobi- lizing the human and financial resources required to overcome the problem. Methods 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,b which was initiated in 1986 to compile, systematize, and disseminate widely the results of anthropometric surveys performed in both develop- ing and developed countries. The specific objectives of the database are to describe the worldwide distri- bution 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 up- dating 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 intemational 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. b WHO Global Database on Child Growth. Updates are avail- able on request from: Nutrition unit, World Health Organization, 1211 Geneva 27, Switzerland. * 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 <5% at a confi- dence level of 95%). * Use of appropriate equipment and standard meas- urement 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 classifica- tion (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 concemed were obtained from the United Nations Population Division (4). Regional prevalences for the indices were esti- mated for each geographical area by weighting the available national prevalences according to the popu- lation 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 develop- ing 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. Esti- mates concemed with underweight, stunting, and wasting were obtained only for those regions where the proportion of children covered by national sur- veys was >70%, and in most cases >80%. Results 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 sur- veys carried 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). 704 WHO Bulletin OMS. Vol 71 1993 WHO Global Database on Child Growth Coverage in Asia. Developing countries in Asia are also scarcely represented in the child-growth data- base 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, Tur- key, 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 coun- tries 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, Brit- ish 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 coun- tries 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 sur- veys). The following countries are still not included in the database: Fiji and New Caledonia (in Melane- sia); 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 sur- veys 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 nation- al 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. 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 Table 1: Population coverage in the WHO Global Data- base on Child Growth, with respect to national surveys, 198092a Total Population Cover- population surveyed age (xl 06) (Xl 06) (%) Africa Northern Africa Eastern Africa Western Africa Middle Africa Southern Africa No. of countries surveyed/total 115.52 89.44 77.4 (34/52) 21.58 37.19 37.24 13.28 6.23 Asia 366.86 Eastern Asia 122.27 Western Asia 19.62 South-eastern Asia 57.66 Southern Asia 167.31 20.75 32.84 32.79 2.41 0.65 326.81 116.14 6.80 53.45 150.42 96.2 88.3 88.0 18.1 10.4 89.1 95.0 34.6 92.7 89.9 (5/6) (13/16) (10/16) (3/9) (3/5) (19/37) (2/5) (5/13) (6/10) (6/9) Latin America 54.63 51.20 93.7 (23/36) Caribbean Central America South America Oceania Melanesia Micronesia Polynesia All developing countries 3.39 16.07 35.17 3.31 97.6 (6/16) 16.07 100.0 (7/8) 31.82 90.5 (10/12) 0.86 0.57 66.3 (3/13) 0.73 0.05 0.08 537.87 0.56 0.01 0.00 468.02 76.7 20.0 0.0 87.0 (2/5) (1/4) (0/4) (79/138) a Under-5-year-old population estimates refer to 1990 according to United Nations Population Division. See ref. (4). and in Fig. 1-3. Most surveys refer to a national ran- dom 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 (<10%, 10-19%, 20-29%, and >30%), corresponding approximately to the quartile distribu- tion 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 preva- lence) and Guatemala (very high) in Central Ameri- ca; Guyana (high), in South America; and Haiti (very high), in the Caribbean. WHO Bulletin OMS. Vol 71 1993 705 M. de Onis et al. Table 2: Prevalencea of underweight, stunting and wast- ing among under-5-year-olds in 79 developing coun- tries, based on national surveys, 1980-92 Survey Sample % under- % % performed size weight stunting wasting Algeria 1992 Bangladesh 1989-90 1914 Barbados 1981 533 Bhutanc 1986-88 3273 Boliviab 1989 2537 Brazil 1989 7314 Burundib 1987 1930 Cameroon 1991 2357 Cape Verde 1983 14 767 Chilec 1986 - China 1987 76 130 Colombia 1986-89 1973 Congo 1987 2429 Costa Rica 1982 1870 C6te d'lvoire 1986 1947 Cubad e 1987 - Djibouti 1989 3750 Dominican 1991 2884 Republic Ecuador 1986 7798 Egypt 1990 - El Salvador 1988 2039 Ethiopia' 9 1992 20 230 Ghana 1987-88 2494 Guatemalab 1987 2230 Guyana 1981 532 Haitih 1990 967 Honduras 1987 3338 Indiai 1988-90 13 548 Indonesia 1987 28 169 Iraq 1991 2565 Jamaica 1989 860 Jordan 1990 6601 Kenya9 1987 - Kiribati 1985 2941 Kuwait 1983-84 2272 Laos 1984 6055 Lesotho' 1981 5467 Madagascark 1983-84 1762 Malawi 1992 3236 Maldives 1983 1485 Malib 1987 925 Mauritania 1990-91 4807 Mauritius 1985 2430 Mexico 1988 7426 Moroccob 1987 3292 Mongolia' 1992 1679 Myanmarb 1983-85 6255 Namibia 1992 2430 Nicaragua 1980-82 1611 Niger 1992 3848 Nigeria 1990 5565 (continued on next column) 9.2 18.1 65.8 64.6 5.3 7.4 37.9 56.1 13.3 38.3 7.0 15.4 38.3 48.1 13.6 24.4 19.0 14.9 2.5 9.6 21.3 32.1 10.1 16.6 23.5 27.1 6.0 7.8 12.4 17.2 22.9 22.2 10.4 19.4 16.5 34.0 10.4 30.0 15.2 29.9 47.7 64.2 27.1 30.5 33.5 57.9 22.1 20.7 33.9 40.6 20.6 33.9 63.9 62.1 39.9 - 11.9 21.8 7.2 8.7 6.4 19.3 14.3 32.2 12.9 28.3 6.4 11.3 36.7 40.1 15.6 26.1 32.8 33.5 27.2 48.6 31.0 24.4 47.6 56.9 23.9 21.5 16.3 27.0 15.7 25.5 12.3 26.4 38.0 49.7 26.2 28.4 10.5 21.8 36.2 32.3 35.7 43.1 5.5 15.5 3.8 4.1 1.6 2.0 5.6 3.0 4.8 0.5 3.6 2.9 5.4 2.0 8.6 0.5 10.7 1.1 1.7 3.5 8.0 7.3 1.4 8.5 4.2 1.9 19.2 3.4 3.4 2.8 4.5 10.8 2.7 10.5 4.5 11.8 5.4 6.3 11.0 15.8 16.2 5.5 3.7 1.7 11.0 8.6 0.6 15.8 9.1 (continued) Omand 1991 764 24.3 Pakistan 1990-91 4037 40.4 Panama 1980 3314 15.7 Papua New 1982-83 27 464 29.9 Guinea9 Paraguay 1990 3389 3.7 Peru 1991-92 7035 10.8 Philippines 1987 2250 32.9 Rwanda9 1991-92 1939 28.6 Sao Tome 1986 2155 17.0 and Principe Senegal' 1991-92 - 21.6 Seychelles 1987-88 836 5.7 Sierra Leone 1990 4595 28.7 Sri Lankab 1987 1994 38.1 Sudanm 1987 15 534 - Swaziland9 1983-84 4133 9.7 Tanzania 1991-92 6097 28.8 Thailandb 1987 1856 25.8 Togob 1988 1396 24.4 Trinidad and 1987 842 6.9 Tobagob Tunisiab 1988 2023 10.4 Uganda 1988-89 3789 23.3 Uruguayc.J 1987 3471 7.4 Vanuatu 1983 1194 19.7 Venezuela 1981-82 6745 10.2 Viet Nam 1987-89 7044 45.0 Yemen 1991-92 - 30.0 Zambia 1992 4899 25.1 Zimbabwe 1988 2485 11.5 20.7 50.0 22.0 43.2 16.6 36.5 38.6 52.2 26.0 29.1 5.1 34.7 27.5 30.3 42.6 22.4 29.6 5.0 18.2 44.5 15.9 19.1 6.4 56.5 44.1 39.6 29.0 7.3 9.2 6.4 5.5 0.3 1.4 4.5 5.2 5.0 5.5 2.0 8.5 12.9 12.5 0.9 6.0 5.7 5.3 3.8 3.1 1.9 1.3 9.4 12.7 5.1 1.3 a % Below -2 SD of the WHO/NCHS reference population. Source WHO Global Child Growth Database (see footnote b, p. 704). b <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 <3rd centile (Cuba). ' 6-59 months (Ethiopia and Senegal). 9 National rural survey covering >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). Survey of rural population of eight states (India). i National surveillance system (Lesotho and Uruguay). k 0-23 months (Madagascar). 0-48 months (Mongolia). m Northern Sudan (Sudan). In Africa, a greater variation seems to occur among regions. The situation in northern Africa (rep- resented 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 WHO Bulletin OMS. Vol 71 1993706 WHO Global Database on Child Growth Fig. 1. Prevalence of underweight children in various developing countries, 1980-92. (Dotted lines represent approxi- mate border lines for which there may not be full agreement). Source: WHO Global Database on Child Growth, 1993. [J <10.0% U 10.0- 19.9% E 20.0- 29.9% E 30.0% + C: date not available WHO 91W5 Africa make it difficult to generalize about the fre- quency of underweight there (the prevalence is mod- erate in Cameroon and Sao 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 sur- veys and contrasting results (low prevalence in Jor- dan 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 cat- egories corresponding to the quartiles of observed values in the 79 countries surveyed: <20%, 20-29%, 30-39%, and .40% (referred to here as low, moder- ate, high, and very high prevalences of stunting, resp.). The prevalences of wasting were originally grouped according to quartiles, producing four cate- gories: <2%, 2-3%, 4-7%, and >8%; however, since both the two first categories are similar to expected values for the reference population (2.3%), they were pooled under one category (<4%), referred to as low prevalence of wasting. The two remaining categories (4-7% and .8%) are referred to as high and very high prevalences of wasting. In broad terms, the differences between geo- graphical areas as regards stunting and wasting resemble the situation for the distribution of under- weight: 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/moder- ate prevalence of stunting and a low prevalence of wasting - is commonly found in countries in Latin America, while the opposite - high/very high preva- lence of both stunting and wasting - is commonly WHO Bulletin OMS. Vol 71 1993 4. '. 'Ai 1-1 707 M. de Onis et al. Fig. 2. Prevalence of stunted children in various developing countries, 1980-92. (Dotted lines represent approximate border lines for which there may not be full agreement). Source: WHO Global Database on Child Growth, 1993. 20.0% U 20.0- 29.9% 0 30.0-30.9% El data not available 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 Thai- land), 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 undernutrition, 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 preva- lences of underweight, stunting, and wasting in devel- oping 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). 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, contributes very little to the absolute number of undernourished children, since there are fewer that 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 reasonably 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 WHO Bulletin OMS. Vol 71 1993708 WHO Global Database on Child Growth Fig. 3. Prevalence of wasted children in various developing countries, 1980-92. (Dotted lines represent approximate border lines for which there may not be full agreement). Source: WHO Global Database on Child Growth, 1993. t%S, XS44ioft _w <.=_knr^t~~~~~~~~~~~~~~~~~~~~~~~~~A : < 4.0% * 4.0 -7.9% [ 8.0% + F] da not available WHOM" 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 chil- dren (Table 5). 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 under- weight and third for wasting and stunting. Western Table 3: Global estimates for the prevalencea and num- ber of underweight, stunted, and wasted children in developing countries % underweight % stunted % wasted Africa Asia Latin America Oceania All developing countries 27.4 (31.6)b 42.0 (154.1) 11.9 (6.5) 29.1 (0.3) 38.6 (44.6) 47.1 (172.8) 22.2 (12.1) 41.9 (0.4) 7.2 (8.3) 10.8 (39.6) 2.7 (1.5) 5.6 (0.1) 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. Africa ranks second for wasting, third for under- weight, 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 con- cerned. 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 indica- tors 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's undernour- ished children. WHO Bulletin OMS. Vol 71 1993 709 M. de Onis et al. Table 4: Regional estimates for the prevalencea of underweight, stunted, and wasted children in developing countries, ranked In descending order % underweight Southern Asia South-eastern Asia Western Africa Eastern Africa Melanesia Eastern Asia Caribbean Central America Northern Africa Southern America 60.5 37.8 32.8 31.0 29.5 21.3 19.4 17.7 11.3 % stunted Southern Asia Eastern Africa South-eastern Asia Melanesia Western Africa Eastern Asia Central America Caribbean Northern Africa 8.4 Southern America 60.3 47.0 43.2 42.2 37.9 32.1 29.8 25.9 25.4 18.1 % wasted Southern Asia Western Africa South-eastern Asia Eastern Africa Northern Africa Melanesia Central America Eastern Asia Caribbean Southern America a % Below -2 SD of the WHO/NCHS reference value. Discussion The data we have presented here document a disturb- ing 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's 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 distri- bution 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 cal- culation of reliable estimates on a regional basis. This global overview is a major improvement over WHO's 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 com- mon among preschool-age children, resulting in small (stunted) rather than thin (wasted) children. Most countries in Asia have high or very high preva- lences of underweight children, while in Latin Ameri- ca, most countries have low or moderate prevalen- ces 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 under- weight. 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, Table 5: Regional estimates for the number of underweight, stunted and wasted children in developing countries, ranked by descending order No. underweight (x106) Southern Asia Eastern Asia South-eastern Asia Western Africa Eastern Africa Southern America Central America Northern Africa Caribbean Melanesia No. stunted (x106) 101.2 Southern Asia 26.0 Eastern Asia 21.8 South-eastern Asia 12.2 Eastern Africa 11.5 Western Africa 2.9 2.8 2.4 0.6 0.2 Southern America Northern Africa Central America Caribbean Melanesia 100.9 39.2 24.9 17.5 14.1 6.4 5.5 4.8 0.9 0.3 No. wasted (xl 06) Southern Asia South-eastern Asia Eastern Asia Western Africa Eastern Africa Northern Africa Central America Southern America Caribbean Melanesia WHO Bulletin OMS. Vol 71 1993 17.3 9.5 7.6 6.0 5.8 5.5 4.6 3.6 2.2 1.9 28.9 4.4 4.4 3.5 2.2 1.2 0.7 0.7 0.1 0 710 WHO Global Database on Child Growth 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 pat- tern, 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 under- weight preschool-age children in developing coun- tries (35.8%) is consistent with a recent value obtained using the same data but a different method- ology (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 popula- tion 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. Sev- eral studies have shown that stunting is associated with poor developmental attainment in young chil- dren (6, 7) and poor school achievement or intelli- gence levels in older children (8, 9). Furthermore, Martorell et al. recently provided the clearest demon- stration 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 con- cern in terms of increased obstetric risks. Finally, stunted children frequently experience social disad- vantages, which themselves may detrimentally affect their development (11). Social equity, as reflected in international human rights law (12),c 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 inequi- table access to it is the main problem,d e it is intolerable that more than 200 million preschool-age c Convention on the Rights of the Child. New York, United Nations General Assembly document AIRES/44/25, 5 December 1989. d See footnote a, p. 703. e WHO Commission on Health and Environment: report of the Panel on Food and Agriculture. Unpublished document WHO/EHE/92.2. children continue to suffer the consequences of undemutrition. The causes of growth retardation are deeply rooted in poverty and lack of education. To continue to allow underprivileged environments to affect children's development not only perpetuates the vicious cycle of poverty but also leads to an enor- mous waste of human potential. If the nutritional well-being of people is a precondition for the devel- opment of societies, it is all the more so where their most vulnerable members - children - are con- cemed. Govemments 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. Acknowledgements We are grateful to Ms J. Evans and Ms M. Blossner for their assistance in preparing this article. Resume L'ampleur mondiale de la malnutrition prot6ino-6nerg6tique d'aprbs la base de donnees de l'OMS sur la croissance des enfants La surveillance de la croissance des enfants est la meilleure faqon d'6valuer leur sant6 et leur etat nutritionnel. Nous avons utilise la base de don- n6es mondiale de l'OMS sur la croissance des enfants, qui couvre 87% des enfants de moins de cinq ans vivant dans les pays en d6veloppement, pour evaluer la pr6valence de la malnutrition pro- teino-energetique dans les differentes r6gions du monde; cette 6tude se fonde sur les r6sultats d'enquetes transversales repr6sentatives menees entre 1980 et 1992 dans 79 pays en developpe- ment d'Afrique, d'Asie, d'Amerique latine et d'Oc6anie. Les resultats confirment l'ampleur du probleme, qui touche plus d'un tiers des enfants du monde. Pour tous les indicateurs (emaciation, retard de croissance et insuffisance pond6rale), la situation la plus favorable, c'est-a-dire des pr6va- lences faibles ou moderees, se rencontre en Amerique latine; dans la plupart des pays d'Asie, les pr6valences sont fortes ou tres fortes, tandis qu'en Afrique, on observe les deux types de situa- tion. Au total, 80% des enfants victimes de malnu- trition vivent en Asie-principalement dans le sud du continent, 15% en Afrique et 5% en Amerique latine. Nous estimons que 43% des 230 millions d'enfants vivant dans les pays en developpement WHO Bulletin OMS. Vol 71 1993 711 M. de Onis et al. presentent un retard de croissance. Celui-ci s'accompagne d'un retard de developpement pen- dant l'enfance et de deficiences fonctionnelles a I'age adulte. Accepter qu'un environnement defa- vorable compromette le developpement des enfants conduit a un enorme gaspillage du poten- tiel humain qui perpetue le cercle vicieux de la pauvrete. Les efforts visant a acc6l6rer le d6ve- loppement economique ne pourront aboutir tant que la croissance et le d6veloppement des enfants ne seront pas assures. References 1. WHO Working Group. Use and interpretation of anthropometric indicators of nutritional status. Bul- letin of the World Health Organization, 64: 924-941 (1986). 2. Keller, W. & Fillmore, C.M. Prevalence of pro- tein-energy malnutrition. World health statistics quarterly, 36: 129-167 (1983). 3. Measuring change in nutritional status. Geneva, World Health Organization, 1983. 4. World population prospects 1992. New York, United Nations, 1993. 5. Second report on the world nutrition situation. Gen- eva, United Nations Administrative Committee on Coordination/Subcommittee on Nutrition, (ACC/SCN), 1992. 6. Lasky, R.E. et al. The relationship between physi- cal growth and infant behavioural development in rural Guatemala. Child development, 52: 219-226 (1981). 7. Powell, C.A. & Grantham-McGregor, S.M. The ecology of nutritional status and development in young children in Kingston, Jamaica. American jour- nal of clinical nutrition, 41: 1322-1331 (1985). 8. Jamison, D.T. Child malnutrition and school perfor- mance in China. Journal of development economics, 20: 299-309 (1977). 9. Moock, P. R. & Leslie, J. Childhood malnutrition and schooling in the Teri region of Nepal. Journal of development economics, 20: 33-52 (1986). 10. Matorell, R. et al. Long-term consequences of growth retardation during early childhood. In: Her- nandez, M. & Argente, J., ed. Human growth: basic and clinical aspects. Amsterdam, Elsevier, 1992, pp. 143-149. 11. Underwood, L.E. The social cost of being short: societal perceptions and biases. Acta paediatrica Scandinavica (suppl.), 377: 3-8 (1991). 12. Universal Declaration of Human Rights. New York, United Nations, 1948. 712 WHO Bulletin OMS. Vol 71 1993