A Fortified Food Can Be Replaced by Micronutrient Supplements for Distribution in a Mexican Social Protection Program Based on Results of a Cluster-Randomized Trial and Costing Analysis

BACKGROUND

Despite positive nutrition impacts, the prevalence of malnutrition among beneficiaries of Mexico's conditional cash transfer (CCT) program remains high. Greater nutrition impact may have been constrained by the type of nutritional supplements provided.

OBJECTIVE

The objective of this study was to inform a potential modification to the supplements distributed to pregnant and lactating women and children.

METHODS

Impact was assessed using 2 cluster-randomized trials (pregnant women, children) run simultaneously. Communities (n = 54) were randomly assigned to the fortified foods provided by the program (Nutrivida women, Nutrisano children) or alternatives: tablets (women), syrup (children), or micronutrient powders for women (MNP-W) and children (MNP-C). Each supplement for women/children contained the same micronutrients based on the formulations of Nutrivida and Nutrisano, respectively. Pregnant women (aged >18 y) were recruited before 25 weeks of gestation and followed to 3 mo postpartum. Children aged 6-12 mo were recruited and followed to age 24 mo. Primary outcomes were anemia for women and length growth for children. Statistical analyses appropriate for cluster-randomized designs were used, and structural equation modeling to estimate dose-response effects. Supplement costs per beneficiary (daily dose for 18 mo) were estimated for production and distribution.

RESULTS

There was no significant difference in change of anemia prevalence between supplement groups in women, or in length growth between groups in children. One daily dose of any supplement was associated with 0.8 cm greater length growth. From baseline to age 24 mo, the prevalence of anemia in the Nutrisano, syrup, and MNP-C groups decreased by 36.7, 40.8, and 37.9 percentage points, respectively (within-group, P < 0.05; between groups, P > 0.05). Costs per beneficiary ranged from $12.1 (MNP-C) to $94.8 (Nutrivida).

CONCLUSIONS

The CCT program could distribute alternative supplements at lower cost per beneficiary without compromising potential for impact. Acceptance among beneficiaries should also be considered in choice of alternatives. This trial was registered at www.clinicaltrials.gov as NCT00531674.

Maternal knowledge and use of a micronutrient supplement was improved with a programmatically feasible intervention in Mexico

In Mexico, the potential impact on child malnutrition from a nutritional supplement (papilla) delivered through a conditional transfer program (Oportunidades) was attenuated by problems of household utilization. A behavioral change through communication intervention was developed to improve supplement utilization. Our study assessed the efficacy of this intervention through the results of a randomized trial. In 2 states (Veracruz and Chiapas) 2 clusters of communities were randomly assigned to intervention or control groups. Data were obtained from 176-198 mothers in intervention and control communities using a survey questionnaire at preintervention baseline and at a 5-mo follow-up. Concordance between reported and observed behaviors was examined through an observational substudy. The 4 behavioral recommendations were: 1) prepare papilla as a pap; 2) administer the preparation every day; 3) administer it between breakfast and dinner; and 4) administer it only to target children. The intervention resulted in a significant increase (P<0.05) in the prevalence of reported correct behaviors in the intervention group compared with the control for 3 of the behaviors: a mean increase of 42.5% for preparing papilla as pap, 64.4% for daily administration, and 61.5% for giving papilla between breakfast and dinner. Administering to a target child increased significantly in Veracruz (from 51.5% to 90.6%), but not in Chiapas (20.6% to 33.3%). Reported behaviors agreed with observed behaviors in the substudy. With the exception of the target-child administration in Chiapas, adopting the recommendations was culturally acceptable and feasible. The results indicate that improvements in household utilization of the supplement can be achieved with a communication intervention that is potentially feasible for implementation on a large scale within the Oportunidades Program.

Maternal energy depletion is buffered among malnourished women in Punjab, Pakistan

Women's nutritional status is believed to deteriorate with increasing reproductive stress (so-called maternal depletion). To evaluate this phenomenon, a new theoretical framework has been suggested that incorporates the concepts of a full reproductive cycle, relative lengths of potential depletion and repletion phases, and initial plane of nutrition. We developed the corresponding statistical model and tested predictions provided by the framework about the effect of reproductive pattern on maternal overall weight change (deltaW) during one reproductive cycle. Seventy-six Pakistani women were classified as well-nourished, marginally nourished or malnourished. The relationship between deltaW and length of all phases of the reproductive cycle, each of which is characterized by varying degrees of reproductive stress, was evaluated with multiple regression analysis. Across the reproductive cycle, well-nourished women had a slight weight increase. Surprisingly, malnourished women gained weight in contrast to marginally nourished women. Also surprisingly, for the latter two groups, periods of moderate reproductive stress were associated with weight loss but periods of high reproductive stress were associated with weight gain. Mechanisms such as efficiency and nutrient partitioning are discussed.

The association between prolonged breastfeeding and poor growth--what are the implications?

The smaller size of breast fed children in infancy and thereafter in malnourished and well-nourished populations has resulted in rushes to judgement that have been shown to be ill-advised. The reasons for the smaller size in malnourished populations is due to retaining the small and sickly child at the breast (reverse causality) and the consequent continuing sickliness of this breast fed child (negative confounding). Once the reverse causality and negative confounding have been taken into account breast feeding improves growth, at least through the second year of life. Thus prolonged breastfeeding should always be fostered, especially in malnourished populations. An exception remains when breast milk may transmit disease to the suckling child. In well-nourished populations the magnitude of the difference between breast fed and weaned children is much less than in malnourished populations, is observed to increase over the first year of life, but to have disappeared by the end of the second year. One may never-the-less be concerned that complimentary feeding practices are not adequate for these children.

Evaluation designs for adequacy, plausibility and probability of public health programme performance and impact

The question of why to evaluate a programme is seldom discussed in the literature. The present paper argues that the answer to this question is essential for choosing an appropriate evaluation design. The discussion is centered on summative evaluations of large-scale programme effectiveness, drawing upon examples from the fields of health and nutrition but the findings may be applicable to other subject areas. The main objective of an evaluation is to influence decisions. How complex and precise the evaluation must be depends on who the decision maker is and on what types of decisions will be taken as a consequence of the findings. Different decision makers demand not only different types of information but also vary in their requirements of how informative and precise the findings must be. Both complex and simple evaluations, however, should be equally rigorous in relating the design to the decisions. Based on the types of decisions that may be taken, a framework is proposed for deciding upon appropriate evaluation designs. Its first axis concerns the indicators of interest, whether these refer to provision or utilization of services, coverage or impact measures. The second axis refers to the type of inference to be made, whether this is a statement of adequacy, plausibility or probability. In addition to the above framework, other factors affect the choice of an evaluation design, including the efficacy of the intervention, the field of knowledge, timing and costs. Regarding the latter, decision makers should be made aware that evaluation costs increase rapidly with complexity so that often a compromise must be reached. Examples are given of how to use the two classification axes, as well as these additional factors, for helping decision makers and evaluators translate the need for evaluation--the why--into the appropriate design--the how.

Food insecurity: consequences for the household and broader social implications

A conceptual framework showing the household and social implications of food insecurity was elicited from a qualitative and quantitative study of 98 households from a heterogeneous low income population of Quebec city and rural surroundings; the study was designed to increase understanding of the experience of food insecurity in order to contribute to its prevention. According to the respondents' description, the experience of food insecurity is characterized by two categories of manifestations, i.e., the core characteristics of the phenomenon and a related set of actions and reactions by the household. This second category of manifestations is considered here as a first level of consequences of food insecurity. These consequences at the household level often interact with the larger environment to which the household belongs. On a chronic basis, the resulting interactions have certain implications that are tentatively labeled "social implications" in this paper. Their examination suggests that important aspects of human development depend on food security. It also raises questions concerning the nature of socially acceptable practices of food acquisition and food management, and how such acceptability can be assessed. Guidelines to that effect are proposed. Findings underline the relevance and urgency of working toward the realization of the right to food.

Impact of food supplementation during lactation on infant breast-milk intake and on the proportion of infants exclusively breast-fed

To evaluate whether milk production can be improved by increasing food intake, a randomized, double-blind, supplementation trial was completed among 102 lactating Guatemalan women. The subjects were undernourished, as indicated by their low values for calf circumference (CC) and the small size of their infants at birth. A high-energy (2.14 MJ/d, HES) and a low-energy (0.50 MJ/d, LES) supplement were distributed 6 d/wk from wk 5 to 25 of lactation. Data were evaluated using repeated-measures analysis of variance on the increments from initial values for each outcome variable with one-tailed tests of statistical significance. The maternal energy intake increased 1.18 MJ/d (P < 0.01) more among the HES than the LES women. Benefit from supplementation was more evident among the more undernourished (CC </= median value, 29.5 cm) women. Among these 53 lower-CC women, infant milk and milk energy intakes were 10% higher (64 g/d and 14 MJ/d, respectively, at wk 25) in the HES than the LES group. After controlling for other determinants of infant milk and energy intakes in regression analyses, the significance of these differences increased to P < 0.04. However, there was no detectable effect on infant growth. Logistic regression analysis was used to show that HES women were significantly (P < 0.05) more likely than LES women to be exclusively breast-feeding their infants at wk 20, the time when the effect of supplementation was most evident. These findings establish that milk production and the duration of exclusive breast-feeding of undernourished women can be improved with the provision of supplemental food.

Serum retinol concentrations in children are affected by food sources of beta-carotene, fat intake, and anthelmintic drug treatment

The provision of vitamin A in food sources of beta-carotene is an alternative to the distribution of high-dose capsules. To examine factors that may influence the success of food-based programs, a study was carried out in Sumatra, Indonesia, of the effect of food sources of beta-carotene, extra dietary fat, and Ascaris lumbricoides infection on serum retinol concentrations in children. Meals and snacks with various amounts of beta-carotene and fat were fed at midday to children 3-6 y of age for 3 wk. Some groups of children were dewormed with the anthelmintic levamisole before the feeding period, whereas others remained infected. Results showed that the incorporation of beta-carotene sources (mainly in the form of red sweet potatoes) into the meal significantly increased serum retinol concentrations. The greatest rise in serum retinol occurred when meals contained added beta-carotene sources and added fat and the children were dewormed. Adding more fat to the meal and deworming the children caused a rise in serum retinol similar to that seen when feeding additional beta-carotene sources. Moreover, the effects of fat and deworming together were additive to the effects of additional beta-carotene sources. When the meal contained additional beta-carotene sources, added fat caused a further improvement in serum retinol concentrations but only if A. lumbricoides infection was low. These studies indicated that food-based interventions in vitamin A-deficient areas might be successful and that other interventions such as increasing dietary fat concentrations and anthelmintic treatment should be considered along with increasing consumption of beta-carotene-rich food.

Linking maternal and infant benefits of a nutritional supplement during pregnancy and lactation

To evaluate the effect of a nutritional supplement on change in women's weight during a reproductive cycle and on the difference in birth weight between one infant and the previous one, we analyzed data on 176 complete reproductive cycles from an experiment that was conducted in rural Guatemala. Women with an initial weight <50 kg were classified as marginally nourished or malnourished. Women whose intake of the supplement was in the top 2 tertiles were distinguished from those whose intake was in the lowest tertile. Linear regression modeling was used to estimate the effect of supplementation on these outcomes and to control for confounding factors. Malnourished women gained weight during the reproductive cycle, but their second (study) infant tended to weigh less at birth than their prior-born infant. Higher intakes of supplement were associated with a less negative difference in birth weight. Marginally nourished women lost weight during the reproductive cycle and their second (study) infant tended to weigh more at birth than their prior-born infant. Higher intakes of supplement were associated with a less negative weight [corrected] trend for the women themselves. Well-nourished women and their infants did not show any of these benefits from supplementation. These findings help explain past contradictory findings on maternal depletion as well as on the benefits of nutritional supplementation for mothers and their infants.

Household participation in the Food Stamp and WIC programs increases the nutrient intakes of preschool children

We examined the effects of household participation in the Food Stamp and WIC Nutrition Programs on the nutrient intakes of preschoolers using data from the 1989-1991 Continuing Survey of Food Intake by Individuals. Nonbreastfeeding children, 1-4 y of age, with 3 d of dietary data and whose households had incomes < 130% of the poverty level were included in the study sample (n = 499). Nutrient adequacy ratios for each of 15 nutrients were the dependent variables in multiple regression models that controlled for the following: age, sex and ethnicity of the individual; income, size and location of the household; schooling of the household head; home ownership; school lunch and breakfast participation; and season in which the interview was conducted. WIC benefits positively influenced (P < 0. 05) the intakes of 10 nutrients. For iron and zinc, the average increase due to WIC represented 16.6 and 10.6%, respectively, of the preschooler recommended dietary allowance (RDA) for these nutrients. The same analyses of the Food Stamp Program revealed increases in five nutrients. For iron and zinc, the average increase due to Food Stamps represented 12.3 and 9.2%, respectively, of the preschooler RDA. The effects of the WIC Program on the intakes of iron and zinc were greater than that of cash income, and neither program affected the intakes of fat, saturated fat or cholesterol.

Sales of food aid as sign of distress, not excess

In 1996 the sale and export of food aid from refugee camps near Uvira, Zaire, prompted a reduction in donated rations. However, research has revealed that the sales did not reflect an excess of food in the camps. They were provoked by the absence of important components of the food basket, by cultural aversion to the staple (maize) and oil provided, by difficulties in food preparation, and by the refugees' limited ability to diversify their diet and cover pressing non-food needs. Food sales improved the micronutrient content of diets but at the expense of energy lost from an already energy-deficient diet. At most 23% of the refugee households were eating sufficient and adequate diets; the poorest one-fifth of households were twice as likely to sell or exchange food as were other households and their diets were the worst. These findings demonstrate the perils of the gap between policy and practice in food-aid distribution.

Research steps in the development and evaluation of public health interventions

Presented is a conceptual framework for planning intervention-related research. Altogether, nine steps in the process of developing and evaluating public health interventions are specified. This process is dynamic and iterative, and all steps are not always required, or need follow in sequence. The framework can be used to set research priorities by verifying where there is sufficient knowledge to move forward and by identifying critical information gaps. It can also help select appropriate research designs, as each step is characterized by certain types of studies. Greater effort is required to move beyond descriptive epidemiological and behavioural studies, to intervention studies. Field trials of public health interventions require particular attention as they are often neglected, despite their significance for public health policy and practice.

Time for a new growth reference

The National Center for Health Statistics growth reference, recommended by the World Health Organization for international use since the late 1970s, has served many useful purposes. Among the most important are the provision of a single set of growth references for the assessment of the general nutritional status of populations of children in diverse settings, as an ancillary tool to screen children for health and nutrition disorders, and as a basis for educational materials that promote improved child care by families. However, because of serious drawbacks due to the origin and type of data used for their construction and the analytical methods applied in their derivation, the suitability of these curves for international purposes has been challenged recently.

Breast milk or animal-product foods improve linear growth of Peruvian toddlers consuming marginal diets

Although breast-feeding is widely accepted as important for infant health, its benefits during the second year of life have been questioned. We analyzed data from 107 breast-fed and weaned Peruvian children living in a periurban community to determine whether breast milk contributed to improved linear growth between 12 and 15 mo of age. Breast-feeding frequency was self-reported; intakes of complementary foods and animal products were estimated from a food-frequency survey. Multivariate-linear-regression analysis was used to predict the length of the children at 15 mo of age. Determinants of length included length and weight-for-length at 12 mo of age (US National Center for Health Statistics standards), interval between 12- and 15-mo measurements, breast-feeding frequency, incidence of diarrhea, and intakes of complementary and animal-product foods. Complementary foods, animal-product foods, and breast milk all promoted toddlers' linear growth. In subjects with low intakes of animal-product foods, breast-feeding was positively associated (P < 0.05) with linear growth. There was a 0.5-cm/3 mo difference in linear growth between weaned toddlers and children who consumed the average number of feedings of breast milk. Linear growth was also positively associated with intake of animal-product foods in children with low intakes of complementary foods. The negative association between diarrhea and linear growth did not occur in subjects with high complementary-food intakes. When the family's diet is low in quality, breast milk is an especially important source of energy, protein, and accompanying micronutrients in young children. Thus, continued breast-feeding after 1 y of age, in conjunction with feeding of complementary foods, should be encouraged in toddlers living in poor circumstances.

Investigating the weanling's dilemma: lessons from Honduras

When complementary foods should be introduced in the diets of infants in poor environments remains controversial. Resolution has been hampered by inadequate study designs. A study in Honduras has demonstrated an experimental design assessing multiple infant and maternal outcomes and provides information for planning sample size and accounting for dropouts in future studies. Further research to understand the cultural, social, and biologic aspects of complementary feeding is needed.

The deterioration in children's nutritional status in rural Chad: the effect of mothers' influence on feeding

OBJECTIVES

This study examined how maternal influence on child feeding modified the deterioration of child nutritional status in Chad.

METHODS

The pattern of height with age was examined in 98 rural Chadian children aged 12 through 71 months from 64 households randomly chosen.

RESULTS

Younger children were more stunted than older ones, probably reflecting secular deterioration in weanlings' nutritional status from 1982 to 1987. Children of mothers with influence over child feeding were taller than children of mothers with less influence, but this held only for the youngest children.

CONCLUSIONS

Height-for-age can be a useful indicator of recent changes in social and environmental effects on child health. The mother's influence may have buffered the negative impact of socioeconomic conditions on child growth.

Association of breastfeeding and stunting in Peruvian toddlers: an example of reverse causality

BACKGROUND

Child feeding recommendations include breastfeeding beyond 12 months, however, some researchers have reported increased rates of malnutrition in breastfed toddlers. A negative association between growth and breast-feeding may reflect reverse causality; that is, the outcome (growth) is a determinant of the predictor (breastfeeding), and not vice versa. We examined this question with data from 134 Peruvian toddlers.

METHODS

A linear regression analysis predicted length at the age of 15 months by length at 12 months, study interval, and 12-14.9-month breastfeeding, complementary food intake, and diarrhoeal incidence. This analysis defined the association between breastfeeding and linear growth. To elucidate the direction of the effect between breastfeeding and linear growth, logistic regression was used to predict the probability of weaning by the end of 14 months. Determinants included weight-for-age (W/A) at 12 months, complementary food intake at 9-11.9 months, and change in diarrhoeal incidence between 9 and 14.9 months.

RESULTS

There was a significant (P < 0.01) interaction of breastfeeding, diarrhoeal incidence, and complementary food intake on length at 15 months. Increased breastfeeding was associated with a 1.0 cm decrease in length gain when dietary intake was low and diarrhoeal morbidity was high, implying that breastfeeding is harmful. The logistic analysis, however, demonstrated that the risk of weaning decreased only when W/A and dietary intake were low and diarrhoeal morbidity was high.

CONCLUSIONS

The negative association between breastfeeding and linear growth reflected reverse causality. Increased breastfeeding did not lead to poor growth; children's poor growth and health led to increased breastfeeding. Children's health must be considered when evaluating the association of breastfeeding with anthropometric outcomes.

The recovery of Guatemalan children with mild to moderate wasting: factors enhancing the impact of supplementary feeding

OBJECTIVES

The purpose of this study was to identify factors that enhance the recovery due to supplementary feeding in wasted children.

METHODS

Recovery rates were obtained in mild to moderately wasted 6- to 48-month-old rural Guatemalan children living in four villages. Children in two villages received a high protein-energy supplement (supplemented children), while children in the other villages received a low protein-energy supplement (nonsupplemented children). The difference in recovery rates between the groups was the attributable benefit. The net supplementation amounted to 11% of the recommended energy intake and its associated nutrients.

RESULTS

Attributable supplement benefits were achieved in younger children (6 to 24 months old) and increased with decreasing weight for length, longer duration of supplementation, and duration of diarrhea, but not with chronicity of wasting.

CONCLUSIONS

Supplementation's effectiveness can be improved in similar populations by programs targeted according to these findings.

Anthropometric reference data for international use: recommendations from a World Health Organization Expert Committee

The World Health Organization (WHO) convened an Expert Committee to reevaluate the use of anthropometry at different ages for assessing health, nutrition, and social wellbeing. The Committee's task included identifying reference data for anthropometric indexes when appropriate, and providing guidelines on how the data should be used. For fetal growth, the Committee recommended an existing sex-specific multiracial reference. In view of the significant technical drawbacks of the current National Center for Health Statistics (NCHS)/WHO reference and its inadequacy for assessing the growth of breast-fed infants, the Committee recommended the development of a new reference concerning weight and length/height for infants and children, which will be a complex and costly undertaking. Proper interpretation of midupper arm circumference for preschoolers requires age-specific reference data. To evaluate adolescent height-for-age, the Committee recommended the current NCHS/WHO reference. Use of the NCHS body mass index (BMI) data, with their upper percentile elevations and skewness, is undesirable for setting health goals; however, these data were provisionally recommended for defining obesity based on a combination of elevated BMI and high subcutaneous fat. The NCHS values were provisionally recommended as reference data for subscapular and triceps skinfold thicknesses. Guidelines were also provided for adjusting adolescent anthropometric comparisons for maturational status. Currently, there is no need for adult reference data for BMI; interpretation should be based on pragmatic BMI cutoffs. Finally, the Committee noted that few normative anthropometric data exist for the elderly, especially for those > 80 y of age. Proper definitions of health status, function, and biologic age remain to be developed for this group.

Adherence to iron supplementation during pregnancy in Tanzania: determinants and hematologic consequences

Limited adherence to iron supplementation is thought to be a major reason for the low effectiveness of anemia-prevention programs. In rural Tanzania, women at 21-26 wk of gestation were randomly given either 120 mg of a conventional (Con) iron supplement or 50 mg of a gastric-delivery-system (GDS) iron supplement for 12 wk. Adherence was assessed by using a pill bottle equipped with an electronic counting device. Adherence in the GDS group was 61% compared with 42% for the Con group. In both groups, women experiencing side effects had about one-third lower adherence. Fewer side effects were observed in the GDS group. In a subgroup of women with a low initial hemoglobin concentration (< or = 120 g/L), the response to the iron supplements suggested that both of the applied doses were unnecessarily high for adequate hematologic response in a population with a marginal hemoglobin concentration. The GDS group appeared to require a dose one-fourth as high as that of the Con group for an equal effect on improving hemoglobin to normal concentrations.

Effect of economic reforms on child growth in urban and rural areas of China

BACKGROUND

Beginning in 1978, China implemented economic reforms to transform the economy to a free-market system. We compared the effect of the reforms on the growth of children in urban and rural areas.

METHODS

Using data from five large cross-sectional surveys conducted between 1975 and 1992, we examined the trends in height for age of children two to five years of age in urban and rural areas. Mean height for age was expressed as the height in centimeters adjusted to a reference value of 99.1 cm for a 42-month-old boy.

RESULTS

Height increased before and during the economic reforms. In 1975, the average height of children in periurban rural areas was about 3.5 cm less than that of children in urban areas. Between 1975 and 1985, the average height of children in periurban rural areas increased by 2.0 cm, as compared with 1.3 cm in urban children. Between 1987 and 1992, the average height of both urban and rural children increased, but the net increase for rural children was only one fifth that for urban children (0.5 vs. 2.5 cm). In a 1990 survey of seven provinces, the rural mean height was 92.5 cm, as compared with the urban mean of 96.9 cm and the reference value of 99.1 cm; 38 percent of rural children had moderate stunting of growth and 15 percent had severe stunting, as compared with 10 percent and 3 percent of urban children, respectively. Differences in height between rural and urban children were greater in provinces in which the average height of children was lower.

CONCLUSIONS

Despite an overall improvement in child growth during the economic reforms in China, the improvement has not been equitable, as judged by increased differences in height between rural and urban children and increased disparities within rural area.

The effects of maternal education on child nutritional status depend on socio-environmental conditions

BACKGROUND

Previous studies have shown an inconsistency in the association between maternal education and child nutritional status across socioeconomic levels. This may be because the beneficial effects of education are only significant when resources are sufficient but not abundant.

METHODS

Associations were examined for differences across socioeconomic levels using data collected from 41 rural communities of Benin for 435 children aged 13-36 months. Village level indicators of household wealth were used together with child z-scores to partition the sample into three levels of socio-environment relative to conditions more or less conducive to child growth.

RESULTS

Using an interactive linear regression model it was shown that for the population of children of women who had no more than 4 years of formal schooling, the association of maternal education and child weight differed significantly across the socio-environment. The relationship was flat and non-significant in the lowest socio-environment, positive and significant (P < 0.05) in intermediate conditions, and weakly positive under the best socio-environment conditions. Among children of mothers attaining higher levels of education, an unexpected negative association was found. It could be that maternal education had enabled women to participate in activities outside the home without simultaneously ensuring adequate child care.

Screening for nutrition interventions: the risk or the differential-benefit approach?

The risk approach has been promoted to improve screening for nutrition interventions on the premise that indicators of risk also predict greater response to interventions. This study tested whether the determinants of the risk of poor growth (eg, low length-for-age) at 36 mo of age were the same as the determinants of differential benefit from food supplementation. The sample included 460 Guatemalan children who were exposed to either a high-energy, high-protein drink (atole) or a low-energy, no-protein drink (fresco) during their first 36 mo of life [INCAP (Institute of Nutrition of Central America and Panama) supplementation trial]. Low maternal stature, poor socioeconomic status, inadequate home diet, high diarrhea rates, and low anthropometry scores at 3 or 6 mo were all determinants of the risk of poor growth. Only indicators of child's thinness at 3 or 6 mo of age (low weight-for-age, weight-for-length, or midupper arm circumference) were determinants of differential benefit from supplementation. Thus, the development of screening indicators should be based on analyses of the predictors of differential benefit, not on conventional risk-factor analysis.

Length screens better than weight in stunted populations

Stunting (low length-for-age) is the most widespread manifestation of growth retardation worldwide. Yet, most nutrition programs use weight-for-age for screening of at-risk children. This study tested whether weight-for-age was an effective screening tool in a severely stunted rural Guatemalan population, using data from the INCAP longitudinal supplementation trial (n = 400). Stunting was defined as length-for-age < -2 SD of the National Center for Health Statistics standards at 3 y of age. Sensitivity and specificity analyses and receiver operating characteristics curves were used to compare weight indicators (weight-for-age, weight velocity and weight-for-length) with length (length-for-age and length velocity) and arm and head circumferences measured during early infancy. Length indicators were clearly superior to weight in predicting stunting (Zda test), and velocities were consistently worse than attained growth. Length-for-age at 6 mo had the best performance, followed by length-for-age at 3 mo, and weight-for-age at 6 and at 3 mo. Velocities, weight-for-length and circumferences were all poor predictors of stunting. Using the cutoff of < -1 SD, length-for-age at 3 mo was the best screening indicator for the early detection of growth faltering. Thus, the current use of weight-for-age, which results in large proportions of at-risk children being missed by screening, greatly limits the potential for impact of nutrition interventions.

Age differences in the impact of nutritional supplementation on growth

Supplementary feeding programs are common in developing countries. These programs often cannot demonstrate an impact on child growth, however, possibly because they tend to reach older children. This study examines the impact of nutritional supplementation on annual growth rates in length and weight from birth to 7 y of age in 1208 rural Guatemalan children. A series of multiple linear regression models is used to control for initial body size, diarrheal disease, home diet, socioeconomic status and gender. During the first year of life, each 100 kcal/d (418 kJ) of supplement was associated with approximately 9 mm in additional length gain and 350 g in additional weight gain; the benefit decreased to approximately 5 mm in length gain and 250 g in weight gain during the 2nd y of life. Between 24 and 36 mo of age, supplement only had a significant impact on length. There was no impact of nutritional supplementation on growth between 3 and 7 y of age. Patterns were the same if supplement intakes were expressed as a percent of recommended allowances or growth was expressed as a percent of the expected rate. These impacts of nutritional supplementation on growth coincide with the ages when growth velocities, as well as growth deficits, are greatest in this population.

Nutritional impact of supplementation in the INCAP longitudinal study: analytic strategies and inferences

From 1969 to 1977 a supplementation trial was conducted in Guatemala to ascertain the effects on physical and behavioral outcomes of improved nutrition in pregnant women and in preschool children. This paper reviews different strategies to analyze the effect of the intervention on physical growth. One strategy compares outcomes in two villages that were randomly allocated to receive Atole, a supplement containing high amounts of protein and energy, with values in two other villages that received Fresco, a beverage containing no protein and little energy. Both supplements contained micronutrients. This comparison of village means gives a probability significance statement (P < 0.005) that the difference in growth was because of the supplement intervention, although it does not specify the aspect of the intervention that caused the effect. Complementary strategies increase the credibility that the effect of the supplement was nutritional. Thus, analysis of the dose response with increasing supplement intake within the villages excludes the possibility that the above findings were the result of knowing which villages received which supplement (i.e., measuring biases). A greater effect in those most likely to respond nutritionally also increases the credibility that the mechanism was nutritional. In studying other behavioral and biomedical impacts of this supplementation intervention, analyses for credibility should always be included.

Differential response to early nutrition supplementation: long-term effects on height at adolescence

BACKGROUND

The classical risk approach to predicting who benefits from an intervention is unsound because it relies on the theoretical assumption that those at risk will necessarily benefit. A better approach to systematically test who benefits from nutrition supplementation is proposed using interactive models.

METHODS

Differential effects of nutrition supplementation during early childhood on stature at adolescence were studied in 245 males and 215 females to identify determinants of long-term benefit from food supplementation. Factors studied included family socioeconomic status (SES) and children's home diet and diarrhoea during the first 3 years of life. To determine whether a factor conferred benefit, the statistical significance of the interaction between this factor and the intervention was tested. Data from the INCAP supplementation trial in Guatemala and from the follow-up of the same subjects at adolescence were used.

RESULTS

Ordinary least squares (OLS) showed that high rates of diarrhoea in males and poor SES in females were significant determinants of benefit from supplementation at adolescence, and that the effects were mediated by length at 3 years old. Results of two-stage least squares (2SLS) analysis showed that length at 36 months, maturation and maternal height were significant determinants of height at adolescence but SES was not.

CONCLUSIONS

Nutrition supplementation in early childhood has long-lasting effects on body size and the larger benefits acquired by some groups of children remain throughout early adulthood. The relevance of these findings for screening and targeting of nutritional interventions is discussed.

Nutritional supplementation during the preschool years influences body size and composition of Guatemalan adolescents

Effects of supplementary feeding during early childhood on body size and composition at adolescence are examined in a population with marked growth failure in the first 3 y of life. The data came from a supplementation trial conducted in rural Guatemala from 1969 to 1977 and a 1988-89 follow-up study of the same subjects at adolescence. Two pairs of villages participated in the trial. One village from each pair received a high protein-energy supplement (Atole), which significantly improved dietary intakes, whereas the other village of the pair received a low-energy, no-protein supplement (Fresco), which did not impact appreciably on dietary intakes. Children from Atole villages grew better during the preschool period than children from Fresco villages. At adolescence, subjects from Atole villages were taller, weighed more and had greater fat-free masses than subjects from Fresco villages. Differences in height at adolescence were slightly reduced in magnitude relative to differences at 3 y of age. However, differences in weight were increased in adolescence relative to 3 y of age.

The effects of malnutrition on child mortality in developing countries

Conventional methods of classifying causes of death suggest that about 70% of the deaths of children (aged 0-4 years) worldwide are due to diarrhoeal illness, acute respiratory infection, malaria, and immunizable diseases. The role of malnutrition in child mortality is not revealed by these conventional methods, despite the long-standing recognition of the synergism between malnutrition and infectious diseases. This paper describes a recently-developed epidemiological method to estimate the percentage of child deaths (aged 6-59 months) which could be attributed to the potentiating effects of malnutrition in infectious disease. The results from 53 developing countries with nationally representative data on child weight-for-age indicate that 56% of child deaths were attributable to malnutrition's potentiating effects, and 83% of these were attributable to mild-to-moderate as opposed to severe malnutrition. For individual countries, malnutrition's total potentiating effects on mortality ranged from 13% to 66%, with at least three-quarters of this arising from mild-to-moderate malnutrition in each case. These results show that malnutrition has a far more powerful impact on child mortality than is generally appreciated, and suggest that strategies involving only the screening and treatment of the severely malnourished will do little to address this impact. The methodology provided in this paper makes it possible to estimate the effects of malnutrition on child mortality in any population for which prevalence data exist.

A methodology for estimating the contribution of malnutrition to child mortality in developing countries

According to conventional methods of classifying cause of death, approximately 70% of child deaths (0-4 y) worldwide are due to a small number of priority infectious diseases which, in turn, receive the vast majority of donor and national resources in the health sector. Despite the long-recognized synergism between malnutrition and infection in the causation of child mortality, malnutrition does not appear as a major cause of death in health statistics from developing countries. Part of the reason for this has been the difficulty of estimating the percent of deaths due to malnutrition, because the conventional methods of classifying cause of death do not recognize the potentiating effect of malnutrition on the disease. The purpose of this paper is to develop and test a simple methodology to estimate the percent of child deaths in a given country or community that is due to malnutrition's potentiating effects on prevailing infectious diseases. The cornerstone of the methodology is knowledge of the strength of the association between malnutrition and mortality in developing countries, as measured in eight prospective studies. These studies reveal remarkable consistency in relative risk across different grades of malnutrition. The mean and SE of relative risk for severe malnutrition is 8.4 +/- 2.1, for moderate malnutrition it is 4.6 +/- 0.9, and for mild malnutrition it is 2.5 +/- 0.3. When applied to survey data from Ethiopia, Malawi, Guatemala and India for illustrative purposes, this methodology indicates that 42-57% of all child deaths in these samples (6-59 mo) are due to malnutrition's potentiating effects on infectious disease, of which 76-89% is attributable to mild-to-moderate malnutrition. This methodology is recommended for use in a variety of policy and planning applications.

Continuing needs for food consumption data for public health policy

There are five broad categories of food-related public health problems in the U.S. for which survey data on food consumption are needed. These relate to reproduction, growth and development, chronic disease, food safety, food insecurity and problems specific to the elderly. The collection and analysis of food consumption data has become increasingly difficult for three major reasons. First, broad societal trends (e.g., ethnicity and use of food away from home) and changes in the food production, processing and marketing sectors have complicated the task. Second, the traditional concerns of monitoring (tracking population means and prevalences) are no longer the only objectives; there is a growing demand for data on habitual intake of individuals and variability in habitual intakes (e.g., to estimate the frequency of acute exposures). Third, data are required at several levels of aggregation (e.g., nutrients, food categories, commodities and name-brand foods) and a high frequency of non-consumption at lower levels of aggregation places high demands on sample size. It is suggested that the current large national surveys be supplemented with special purpose surveys that meet individual agency needs, and that principles and methods of state and local monitoring be further developed and implemented.

Weaning in southern Brazil: is there a "weanling's dilemma"?

In Pelotas, Brazil, 400 newborns from low income families were followed-up until 26 wk of life to study the relationship between their feeding patterns and growth as modified by access to water and by diarrhea. Effects of access to water were the strongest among non-breastfed infants. In houses without indoor water taps, the weight gain of non-breastfed infants during the first 3 mo was approximately half that of partially or predominantly breastfed infants (P < 0.001). In houses with indoor water taps, non-breastfed infants' growth was similar to or exceeded that of predominantly breastfed infants from 2 mo. Predominantly breastfed infants' growth was similar in houses with and without water taps. Breastfed infants had less weight loss per day of diarrhea than non-breastfed infants during the first 4 mo and less diarrhea through 6 mo of life, particularly in houses without taps, in which diarrhea was most prevalent. The existence of a "weanling's dilemma" was approached by comparing the duration of the detrimental effects of not breastfeeding (i.e., 0-3 mo in this study) with the age at which breast milk alone becomes less than optimal for growth (i.e., at 5 mo). Because these two points did not coincide, we conclude that there is no "weaning's dilemma" in this population.

Evaluation of indicators for use in vitamin A intervention trials targeted at women

This paper examines the ability of three indicators to detect changes in women's vitamin A status. Serum retinol concentration, milk vitamin A concentration, and milk vitamin A per gram milk fat were used to assess the vitamin A status of mildly deficient Indonesian women before and after supplementation in a randomized intervention trial. Choice of indicator made a fourfold difference in the sample size required to measure a statistically significant change in vitamin A status. Milk vitamin A per gram milk fat was the best indicator of response, milk vitamin A concentration was intermediate, and serum retinol concentration performed most poorly. Serum retinol concentration was equally responsive across the range of vitamin A status in this population. The milk indicators were more responsive among women of lower status than women of higher status. Milk vitamin A is an efficient indicator for monitoring the effects of vitamin A interventions in women.

Effects of maternal nutritional status and maternal energy supplementation on length of postpartum amenorrhea among Guatemalan women

To investigate the extent to which better maternal nutrition leads to reduction in length of postpartum amenorrhea, multivariate-logistic and linear-regression analyses were applied to data on 339 mother-infant pairs from the longitudinal Guatemalan Four Village Study, 1969-1977. Maternal triceps skinfold thickness was negatively associated with length of amenorrhea when infant supplementation (a proxy for reduced suckling) was accounted for. However, its effect was small: amenorrhea was only 0.5 mo shorter among women at the 75th percentile than among those at the 25th, equivalent to less than even one additional child during the women's reproductive years. Maternal supplementation was not associated with length of amenorrhea when infant supplementation was controlled. This is in contrast to previous studies in which breast-feeding or infant supplementation was not controlled. These results suggest that infant, not maternal, supplementation influences length of postpartum amenorrhea, and that maternal nutritional status has minimal influence.

Epidemiologic evidence for a potentiating effect of malnutrition on child mortality

OBJECTIVES

Despite broad agreement that severe malnutrition contributes to child mortality in developing countries and that malnutrition has a physiologically synergistic relationship with morbidity, evidence of an epidemiologic synergism has been lacking. Also, the literature provides conflicting evidence concerning the existence of elevated mortality among children with mild to moderate malnutrition. A review of published population-based studies of anthropometry-mortality relationships was undertaken to clarify these relationships.

METHODS

Six studies with the relevant data were reanalyzed to test for synergism and elevated mortality in mild to moderate malnutrition.

RESULTS

The results demonstrate that mortality increases exponentially with declining weight for age. This effect is consistent across studies and there is no apparent threshold effect on mortality. The primary difference across studies is in baseline levels of mortality, which determine the quantitative impact of malnutrition on mortality in a population.

CONCLUSIONS

These results indicate that mild to moderate malnutrition is associated with elevated mortality and that there is an epidemiologic synergism between malnutrition and morbidity. This previously undemonstrated finding has significant implications for child survival policies and research.

High dose vitamin A supplementation of breast-feeding Indonesian mothers: effects on the vitamin A status of mother and infant

For regions where vitamin A deficiency is common, high dose vitamin A supplementation of lactating mothers is currently recommended, but the effects of this intervention have not been carefully evaluated. We conducted a randomized, double-blind trial in which 153 Indonesian mothers 1-3 wk postpartum received either a capsule containing 312 mumol of vitamin A as retinyl palmitate or a placebo. Mothers' serum retinol concentrations in the vitamin A group tended to be lower than in the placebo group at baseline but higher at 3 mo postpartum (1.39 vs. 1.24 mumol/L, P = 0.03) and 6 mo postpartum (1.23 vs. 1.08 mumol/L, P < 0.01). The milk retinol concentrations of the vitamin A group were higher than those of the placebo group by 0.48 to 1.18 mumol/L at 1-8 mo postpartum (P < 0.05). Among the infants at 6 mo of age, the prevalences of low serum retinol concentration (< 0.52 mumol/L) were 36 and 15% in the placebo and vitamin A groups, respectively (P < 0.005), and the prevalences of low vitamin A stores (assessed by relative dose response) were 23 and 10%, respectively (P < 0.03). High dose vitamin A supplementation of lactating mothers is an efficacious way to improve the vitamin A status of both mother and breast-fed infant.

Testing the effects of nutrient deficiencies on behavioral performance

The association between specific nutrient deficiencies and poor performance on behavioral tests has been documented for several nutrients. The determination of causality, however, remains elusive. This paper presents the essential criteria for a valid test of causality. Findings from experimental studies in which a nutritional treatment was randomly allocated can be summarized in a statistical statement about the probability that the nutrient treatment caused the behavioral response. Criteria for assessing the internal validity of these studies are examined in terms of whether alleviation of a nutrient deficiency did or did not produce a detectable behavioral response. The plausibility of such a causal inference is dependent on its congruency with known or theorized biological and behavioral mechanisms. External validity describes the extent to which inferences from internally valid studies may be applicable to other populations or circumstances. In addition to these scientific considerations, some of the ethical issues of nutrient-treatment trials are also discussed. All of these considerations provide a better basis for judging whether public health action would be worthwhile than do observed associations that could actually be due to other causes.

Growth charts only marginally improved maternal learning from nutrition education and growth monitoring in Lesotho

A study done in Lesotho in 1985-1986 assessed whether growth charts increased the impact of nutrition education and growth monitoring on maternal learning about weaning practices and diarrhea. Seven hundred and seventy six mothers were given three monthly sessions of group nutrition education along with growth monitoring of children and individual counseling. Growth charts, which were taught to one of two groups, fostered learning but only on issues related to diarrhea and only among new clinic attendants, mothers with less than secondary schooling and mothers of malnourished children. These benefits, however, were small (differences less than 10%) compared with the overall impact of the nutrition education and growth monitoring intervention (increases between baseline and post-intervention were greater than 50% for some questions). Our findings suggest that well-designed clinic-based nutrition education and growth monitoring can have a significant impact on maternal nutrition knowledge. Teaching growth charts to mothers may not be necessary for obtaining such results in programs conducted under ideal conditions. More research is needed to determine under what circumstances, for what purposes and for whom growth charts may be beneficial.

Use of positive-negative deviant analyses to improve programme targeting and services: example from the TamilNadu Integrated Nutrition Project

This paper describes the characteristics of southern rural Indian children who grow best (positive deviants) and worst (negative deviants) as compared to median growers. A 100 each of positive and negative deviants and 120 median growers were selected after analysing the 12-month growth patterns (weight-for-age) of 2954 children enrolled in the TamilNadu Integrated Nutrition Project (TINP), a major health and nutrition intervention project covering nearly one million children in rural south India. The determinants of poor growth that have been left unaddressed by 6 years of TINP exposure are delineated to address the question of what more needs to be done. Further, the rationale for differential targeting of services to negative deviants and to median growers is discussed, as are the implications for programme evaluation. Data indicate that the next generation of projects targeted at the most needy (negative deviants) should address the issues of gender discrimination in childcare, of breastfeeding, of diarrhoeal disease, and of maternal empowerment. Such interventions will, however, not improve the growth of median growers in the direction of positive deviance. Instead, programmes targeted at the median growers need to support the hygienic use of nonbreast milk supplements. Improving family wealth will also improve the nutritional status of the median growers, but less so than for the negative deviants.

A new definition of maternal depletion syndrome

BACKGROUND

Although the term "maternal depletion syndrome" has been commonly used to explain poor maternal and infant health, whether such a syndrome actually exists remains unclear. This uncertainty may be due to the lack of a clear definition of the syndrome and the absence of theoretical frameworks that account for the many factors related to reproductive nutrition.

METHODS

We propose a new definition of maternal depletion syndrome within a framework that accounts for potential confounding factors.

RESULTS

Our conceptual framework distinguishes between childbearing pattern and inadequate diet as causes of poor maternal health; hence, our definition of maternal depletion syndrome has both biological and practical meaning. The new definition is based on overall change in maternal nutritional status over one reproductive cycle in relation to possible depletion and repletion phases and in relation to initial nutritional status.

CONCLUSIONS

The empirical application of this approach should permit the testing of the existence of maternal depletion syndrome in the developing world, and the distinction between populations where family planning will alleviate maternal depletion and those in which an improved diet is also necessary.

The mediating effect of maternal nutrition knowledge on the association between maternal schooling and child nutritional status in Lesotho

The present study tested whether maternal nutrition knowledge was a mediating factor in the association between maternal schooling and child nutritional status, and whether the mechanism involved differed according to socioeconomic status. The data were collected in Lesotho on 921 mother-child pairs and included scores from a nutrition knowledge test, socioeconomic and demographic information, and the child's anthropometric data. A wealth factor derived from a factor analysis was used to stratify the sample into two socioeconomic groups. Two-stage least-squares estimation was used to test the mediating role of nutrition knowledge between maternal schooling and child weight-for-age. Results showed that both the importance of maternal schooling and the mechanism by which it affects the child's weight-for-age are contingent upon the family's socioeconomic status. While maternal schooling was positively associated with weight-for-age for both wealthier and poorer households, the size of the effect was much larger for the latter group. The effect of maternal schooling on weight-for-age was mediated by the mother's nutrition knowledge only among wealthier households. These results imply that, in Lesotho, nutrition education for mothers could contribute to improving children's growth, but only in households that have access to a minimum level of resources. For poorer households, nutrition education would not be sufficient.

The complementary effect of latrines and increased water usage on the growth of infants in rural Lesotho

The effects of water quantity and sanitation, alone and in combination with each other, on infant weight gain and length gain were examined. Data on 119 infants were collected from 20 villages in rural Lesotho between July 1984 and January 1985. The interactions between sanitation and increased water usage for weight gain (p = 0.007) and length gain (p = 0.006) were significant after potential confounding was controlled. The biggest growth effects were dependent on families possessing a latrine and increasing their use of water during the warm, wet season. Infants gained 1.031 kg (95% confidence interval (CI) 0.420 to 1.642) and 2.028 cm (95% CI 0.523 to 3.533) more when both positive factors were present, as compared with only having a latrine. Increasing water usage compared with not increasing water usage resulted in only 0.105 kg (95% CI -0.175 to 0.385) more weight gain and -0.309 cm (95% CI -1.005 to 0.387) more length in the absence of a latrine. Similarly, infants gained 1.106 kg (95% CI 0.484 to 1.728) and 2.076 cm (95% CI 0.559 to 3.593) more if both factors were operating than did infants whose families only increased their water usage. In the nonincreased water group, the difference in growth between having and not having a latrine was 0.180 kg (95% CI -0.093 to 0.453) and -0.261 cm (95% CI -0.951 to 0.429). Water supply programs should emphasize use of more water for personal hygiene, and sanitation programs should install toilet facilities where water usage is high or has been increased because of an educational program.