Nutritional Diseases

Protein-energy malnutrition

PEM can refer to either acute or chronic undernutrition. Because children less than 5 years of age are among the most acutely affected by undernutrition, assessment of this age group by anthropometry is usually done to determine PEM prevalence in a population (see "Indicators of Acute Undernutrition"). In general, acute undernutrition results in wasting and is assessed by an index of weight-for-height (WFH); however, edema of the extremities may be associated with acute undernutrition in which case, a clinical assessment is necessary. Chronic undernutrition produces stunting and typically results in a diminished height-for-age index.

The prevalence of moderate to severe acute undernutrition in a random sample of children less than 5 years of age is generally a reliable indicator of this condition in a population. Since weight is more sensitive to sudden changes in food availability than height, nutritional assessments during emergencies focus on measuring WFH. Also, WFH is a more appropriate measurement for ongoing monitoring of the effectiveness of feeding programs. As a screening measurement, the mid-upper arm circumference (MUAC) may also be used to assess acute undernutrition, although there is not complete agreement on which cutoff values should be used as indicators. Nutritional assessment methods are fully described in the Rapid Nutrition Assessment Manual. *

* Available from the International Health Program Office (IHPO), CDC, 1600 Clifton Road, MS F-03, Atlanta, GA 30333, 404-639-0308.

Anthropometric indices such as WFH and height-for-age are interpreted by comparison with a "reference population". Index values are assigned a "Z-score" based on the number of standard deviations above or below the median value in the reference population. Currently, the World Health Organization (WHO) recommends the use of the CDC/NCHS reference population for nutritional assessments in all countries (22). Before the mid-1980's, anthropometric data was reported as a percentage of the median of the reference population value. Current international guidelines, however, recommend the use of Z-scores to report nutritional assessment data. Tables in this report define acute undernutrition on the basis of percentage median in order to allow comparisons of recent data with data from surveys performed before the mid-1980s.

In a well-nourished population in which WFH values are distributed normally (i.e., the reference population), approximately 3% of children less than 5 years of age will have WFH Z-scores of less than -2. For less developed countries with lower "normal" nutritional intake levels, 5% of the children may have a Z-score less than -2 when compared with the reference population median, particularly at certain times of the year. Relief organizations agree that a nutritional emergency exists if greater than 8% of the children sampled have a Z-score less than -2. An excess of even 1% of children with Z-scores less than -3 indicates a need for immediate action. Acute PEM prevalence rates have been high in recent famine-affected populations, especially in Africa (Table 6).

In addition, acute undernutrition prevalence rates have been elevated in many displaced and refugee populations during the past 12 years, ranging as high as 50% in eastern Sudan in 1985 (Table 5) and (Table 7). PEM rates have decreased rapidly in situations where effective emergency relief operations have been mounted promptly, i.e., Thailand (1979) and Pakistan (1980). However, in other emergencies, such as in Somalia (1980) and Sudan (1985), PEM rates have remained high (greater than 20%) for 6-8 months. Of even greater concern is the observation that acute undernutrition rates among Somali refugees in Ethiopia (1988-1989) actually increased 6 months after a relief program was launched. Although most high acute undernutrition prevalence has been associated with inadequate food rations, it appears that malnutrition developed among Kurdish children 1-2 years of age in Turkey within a period of 1-2 months, primarily because of the high incidence of diarrheal diseases in the camps (10). Among internally displaced civilian populations, high PEM prevalence has been associated with the intentional use of food as a weapon by competing military forces (30).

The use of serial anthropometry surveys as monitoring tools has certain limitations when mortality rates are high. For example, an analysis of anthropometric data from two cross-sectional surveys in a refugee camp in Sudan in 1985 initially implied a relatively stable nutritional situation. In January, the prevalence of acute malnutrition in children less than 5 years of age was 26.3%; in March, the rate was 28.4%. During these two months, almost 13% of the children in the camp died, mainly from measles and diarrheal diseases. In this instance, the elevated child mortality rate masked diminished nutritional status in the population. Many malnourished children in the first survey, who had died, were "replaced" in the second survey sample by surviving children whose nutritional status had meanwhile deteriorated (31). Thus, anthropometry data need to be interpreted in the context of concurrent mortality rates.

Micronutrient deficiency diseases

In addition to PEM, micronutrient deficiencies play a key role in nutrition-related morbidity and mortality. The importance of micronutrient deficiencies in famine-affected and displaced populations has recently been extensively documented. In addition to deficiencies of vitamin A and iron, conditions widely recognized as important childhood problems in developing countries (i.e., epidemics of scurvy and pellagra) have also been reported in refugee populations during the past decade (Table 8).

Vitamin A deficiency

The most common deficiency syndrome in emergency affected populations is caused by lack of vitamin A. Ocular signs of vitamin A deficiency -- known as xerophthalmia -- include night blindness and Bitot's spots in the earlier stages. Xerophthalmia progresses to corneal xerosis, ulceration and scarring, and eventually blindness. Signs of xerophthalmia were detected in 7% of children surveyed in one region of Somalia during the drought of 1986-1987 (27); 2.1% in drought-affected Niger in 1985 (24); 4.3% among Kampuchean refugees in Thailand (36); and 2.7% in a region of Mauritania in 1984 (23). Recent data suggest that vitamin A deficiency is linked with high childhood mortality (37-38).

Famine-affected and displaced populations often have low levels of dietary vitamin A intake before experiencing famine or displacement, and therefore, may have very low vitamin A reserves. Furthermore, the typical rations provided in large-scale relief operations lack vitamin A, putting these populations at high risk. In addition, some communicable diseases that are highly incident in refugee camps -- measles and diarrheal diseases -- rapidly deplete vitamin A stores. Depleted vitamin A stores need to be adequately replenished during recovery from these diseases to prevent the deficiency from becoming clinically important.

Vitamin C deficiency (scurvy)

Although scurvy has been reported rarely in stable populations in developing countries, many outbreaks have occurred in displaced and famine-affected populations in recent years, primarily because of inadequate vitamin C in rations. In 1981-1982, an outbreak of more than 2,000 cases of scurvy occurred in the refugee camps of the Gedo region of Somalia. These Ethiopian refugees had traditionally obtained sufficient dietary vitamin C from camel's milk. Once in refugee camps they subsisted on a ration devoid of vitamin C. The outbreak was precipitated when local markets, where refugees had exchanged rations for fresh fruit and vegetables, were suddenly closed (39).

Active surveillance for scurvy among Ethiopian refugees in Somalia and Sudan in 1987 revealed cumulative incidence rates of up to 19.8% in some camps, with initial onset reported between 3-10 months after the arrival of the refugees (32). Cross-sectional surveys performed in 1986-1987 reported point prevalence rates as high as 45% among females and 36% among males; prevalence increased with age. The prevalence of scurvy was associated with the period of residence in camps, and the time exposed to rations lacking in vitamin C. In 1989, a population survey of children less than 5 years of age in Hartisheik camp in eastern Ethiopia in 1989 found the prevalence of clinical scurvy to be 2% (19). The international community has not developed an adequate strategy to prevent scurvy in refugee camps at the Horn of Africa, as demonstrated by an outbreak that took place among adult males (former Ethiopian soldiers) in a camp in eastern Sudan during 1991 (Bhatia R, personal communication, October 1991).

Niacin deficiency

Pellagra is the condition resulting from a severe deficiency of biologically available niacin in the diet. Once common in the southeastern United States, Italy, and Spain, pellagra now occurs mainly in maize- or sorghum-consuming populations in southern Africa, North Africa, and India. An outbreak of pellagra occurred in Malawi among Mozambican refugees between July and October 1989. Eleven camps reported a total of 1,169 patients; 20% of the patients were children less than 5 years of age (40). The French agency Medecins Sans Frontieres (MSF) instituted active surveillance at the time. Another outbreak occurred between February and October 1990 with 17,878 cases reported among 285,942 refugees in the same 11 sites (attack rate of 6.3%). More than 18,000 cases of deficiency were reported from all districts hosting approximately 900,000 refugees in southern Malawi, for an overall attack rate of 2.0% (35). Food rations contained an average of 4.9 mg of available niacin/person/day; the Food and Agriculture Organization (FAO)/WHO recommendations for daily niacin intake range from 5.4 mg for infants to 20.3 mg for adults. This outbreak occurred when relief efforts failed to include an adequate supply of groundnuts (peanuts), the major source of niacin in refugee rations. The lack of variety in basic relief rations is a major risk factor for pellagra and other micronutrient deficiency syndromes. Treatment of maize flour with lime (which converts niacin to a biologically available form of niacin) and the inclusion of beans, groundnuts, or fortified cereals in daily rations increase the total intake of available niacin and will prevent the development of pellagra (35).

Anemia

The high prevalence of anemia in refugee and displaced populations has been noted in few publications to date, but unpublished data from CDC assessments suggest that it may be a serious problem in some areas. In 1990, a survey of Palestinian refugees in Syria, Jordan, and the West Bank revealed that the prevalence of anemia among infants and young children was between 50% and 70%. Anemia among both nonpregnant and pregnant women was shown to be 25%-50%, whereas a low anemia prevalence rate was found among the male population. (In this study anemia was defined as a hemoglobin concentration of less than 11 g/dL among children and less than 12 g/dL among nonpregnant women. Pregnant women were considered to be anemic if their hemoglobin concentration was less than 11.5 g/dL during either the first or third trimester, or less than 11.0 g/dL during the second trimester.) These findings suggest that iron deficiency, which preferentially affects women and children, was the primary cause of anemia in this population.

A 1987 study among refugees in Somalia demonstrated an anemia prevalence rate of 44%-71% among pregnant women, with that proportion being even greater if only women in the third trimester of pregnancy were considered. The cutoff point for hemoglobin concentration in this study was 10 g/dL; with the WHO cutoff of 11 g/dL, the prevalence would have been greater. Among children 9-36 months of age, 59%-90% were below the 10 g/dL cutoff. The inadequacy of the general ration was identified as the major factor causing iron deficiency anemia in this population. In a 1990 study, the prevalence rate of anemia was 13% among children less than 5 years of age in an Ethiopian camp for Somali refugees (Save the Children Fund UK, unpublished data). In addition to dietary iron deficiency, the high incidence of malaria in many refugee populations probably contributes to the high prevalence of anemia in children. This high prevalence of anemia found in some refugee populations may not be significantly greater than that found in local, non-refugee populations, since the latter group has been poorly documented. Nevertheless, anemia may be an additional important preventable risk factor for high mortality in refugee populations. The high prevalence of anemia is often correlated with a subset of the population with severe anemia (hemoglobin (Hb) less than 5 g). Severe anemia in itself can be a major cause of mortality for young children and pregnant women during the peripartum period.

Other micronutrient deficiencies

Beriberi (thiamine deficiency) has been reported from several refugee populations that subsist on rice-based food rations (Thailand, 1980; Guinea, 1990). Data regarding iodine deficiency in displaced populations are difficult to find, anecdotal evidence suggests that iodine deficiency, as evidenced by the presence of goiter, has been a problem in at least some camps in Pakistan and Ethiopia (CDC. Toole M, trip report, 1991).


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