SAHEL NUTRITION SURVEY 1974 Theodore I. Kloth, M.D. Medical Epidemiologist Bureau of Smallpox Eradication Center for Disease Control Atlanta, Georgia 30333 Field Investigators Winthrop A. Burr, M.D. Jeffrey P. Davis, M.D. C Gary Epler, M.D. , Cornelius A. Kolff, M.D. Robert L. Rosenberg, M.D. -' C. C. ifs rr~k n r4V Algiers TUNISIA SPANISHEALGERIA Cairo SAHARA CAPE VERDE IS. ENEG. Khartoum Dakar THE GAMBIA SUDAN F.T.A. Banjul anjul GUNADiot GUINEA*I1SSALBrssau" Conakry DAHOMEYPorto Nov•M o ETHOPIA Freetor IVORY NIGERIA SIERRALEONE COAST GHANA Lagos Mono a Abidjan Acca CENTRALAFRICAN TOGOCMEC REPUBC RaoundI QUATORIALGUINA Maab eBAND Kishs Bu.m =. :r • t' MBA TAAI ZANOB Lome~ig Maqe e rea• Dares~aa ANGOLAAN 04MLAA" Maseru As a result of severe drought and resultant crop failures for the past several years, superimposed on demographic and agricultural changes in the area, inhabitants of the West African Sahel* have been subjected to food shortages which-have resulted in increased malnutrition. During times of food scarcity, certain customs of West African culture may dictate that children receive less than their proportionate share of food. Young children, as a result of their rapid growth rate and their increased susceptibility to infection, are at a greater risk than adults to the effects of nutritional depiivation. Body measurements of children are con­ sidered a sensitive index of nutritional status and growth patterns are likely to be significantly different from normals if undernutrition is present; anthropometrics of children are accordingly central to this survey. Height and weight are the two most commonly used measures of physical growth, and with sufficient care and adequate instruments, accurate measure­ ments can be made on many children in a relatively short time. Observed height and weight are commonly compared with expected age specific values. Height for age is observed height in relation to expected height of a reference child of the same sex and age. Chronic undernutrition results in linear growth retardation ("stunting" - a deficit in height for age) often .accompanied by a proportionate failure to gain weight. Weight for age is observed weight in relation to expected weight of a reference child of the *The Sahel is both a climatic region and a vegetation zone which lies immediately south of the Sahara, from the Atlantic Ocean on the west to the Red Sea on the east. It begins at approximately 15 degrees north and extends northward in most areas for about 300 miles to 20 degrees north latitude. 2 same sex and age. This index, weight for age, consists of two separate nutritional states - chronic undernutrition (as described above) and acute undernutrition. Acute undernutrition results in a loss of body weight which is disproportionate to body length ("wasting" - a deficit in weight for height). Therefore, in order to identify more clearly the effects of acute undernutrition (wasting of body mass) that may be superimposed upon a population suffering from chronic undernutrition (stunting of body length), it is more useful to emrloy weight for height determinations, i.e. observed weight in relation to expected weight of a reference child of the same sex and height.* The advantages of this last anthronometric index, weight for height, are multifold. First, it is nearly impossible in rural West Africa to ascertain exact ages of children (which are obviously necessary in the determination of weight or height for age.) Secondly, weight for height has been found to be relatively independent of sex, race, and age (up to about age 10). Repeated observations have shown that well-nourished African children do follow the western standards of weight for height reference data. In other words, in young children, weight for height remains quite constant under most conditions except acute undernutrition (and overnutrition) and is thus a most useful anthropometric index in disasters in which food scarcity and famine are prominent. *The weight for height reference values used here are the age specific median values for weight and height of the Stuart-Meredith reference population. 3 The criterion in this study for the "acute malnutrition threshold" (AMT), below which a child can clearly be considered to be undernourished, has been designated as 80% of the median weight for height values derived from the Stuart-Meredith reference population. Because this value closely approximates the third percentile of the Stuart-Meredith reference population within this age range, about 3% of a normal population would be expected to fall below this level. Any appreciable excess over 3% below the AMT (80%) is therefore indicative of a population which has recently been subjected to food shortage. In this study, the nutritional status of a population group will also be characterized by calculating the mean of all of the individual percent of median weight for height values. For convenience, this "mean percent of median" weight for height will be designated the MPM. The following report represents the latest information on the current nutritional status of inhabitants of certain defined regions in five Sahelian countries - Chad, Niger, Mali, Mauritania, and Upper Volta. It is the first nutrition related study that examines certain regions of these countries suspected to be affected by the drought by a systematic probability random sampling method, and as such contains information which may validly be extrapolated to that part of the country from which the sample was chosen. Methods The problems of obtaining adequate population data for establishing a statistically sound sampling base are particularly difficult in the 4 West African Sahel, where census data and registration systems are inadequate at best. Nevertheless, attempts were made to obtain the most up-to-date census information available so that a systematic probability sample could be drawn. The initial step was to specify and limit the universe from which the sample was to be drawn, with the understanding that all extrapo­ lations and conclusions from the data would be applicable only to that universe. The sampling methodology was geared to producing estimates for the aggregate drought affected area sampled within each country. Estimates for subsets of these areas, therefore, cannot be statistically reliable due to an insufficient number of clusters within these subsets. Furthermore, the group of children drawn from an individual village are not necessarily representative of that village but are simply a geographic clustir which when taken collectively with all clusters, are representative of the sample area. In some cases the report touches on large differences between regions within a country. Although not statistically valid, they suggest hypotheses which could be tested with more extensive sampling. The inability to reach all of the selected villages within the sample represents potential bias in the estimates made for the universe. Population estimates for the total area and for the divisions within this area were obtained, although it was recognized that within some areas only the crudest population estimates would be available. The number of sampling units per major division was computed based on population proportions in each division. This division was then visited 5 and individual village population data, again based on best available population estimates, was cumulated and the sampling unit selection made by systematic interval selection. Once within the village, the in­ vestigator selected a random starting point. He then went house to house, in an orderly fashion, and measured all children 65 centimeters to 115 centimeters, (about 6 months through 6 years of age). Twenty-five children were examined in each cluster. If less than 25 children were found in the village, the investigator moved to the geogranhically nearest village and continued the process until 25 children were measured. In addition to gathering the heights, weights, and ages (when known) of the 25 children in each village, certain additional information was recorded. General information about the village was usually obtained from the chief in collaboration with the elders. More specific information was gathered from individual households. Anecdotal information sought included the number of children examined who had evidence of avitaminoses, the number of individuals in the sample households and the village, the number of cases of measles and deaths in the sample households and the village, the amount and type of food available, the presence or absence of relief supplies, the frequency of relief operations, and the nresence of any other serious infectious disease currently present in-the village. This information-was obtained without random samnling methods and without specific judgemental criteria. Therefore, while it contains useful in­ formation, broad inferences based on this material should be avoided. 6 The areas designated for study in this survey are noted in Figure I. They include: Chad, the prefectures of Kanem and Lac; Mali, the cercles of Keyes, Yellimane, Nioro in the Kayes Region, Nara in the Bamako Region, and Gourma Rharous, Gao and Ansongo in the Gao Region; Mauritania, specific areas within Regions I through VII; Niger, the Departments of Niamey, Dosso, Tahoua, Maradi, Zinder, and a portion of Agadez; and Upper Volta, the cercles of Djibo, Barsologho, Kongoussi, Dori, and Ouadalan. Results - General Within the sampled portions of the Sahellan countries, a total of 3,928 children between