Respiratory tract and diarrheal infections of breast-fed infants from birth to 6 months of age in household contexts of an Egyptian village.

OBJECTIVE: To investigate the pattern of respiratory tract infections (RTI) and diarrhea among brest-fed infants and the impact of birth weight, maternal diet during lactation, and household socioenvironmental conditions on these illnesses. DESIGN: A longitudinal household-based study of infant morbidity from birth to 6 months of age. SETTING: Kalama village, Egypt. SUBJECTS: Morbidity information was obtained for 119 infants; 80 had longitudinal records over the first 6 months of age. RESULTS: Birth weights were normally distributed and the mean was comparable to the National Center for Health Statistics reference median. Most infants experienced growth faltering and increased illness episodes during 3 to 6 months of age. Infants with RTI during the first 3-month period were at a significantly higher risk of developing subsequent RTI compared with infants without earlier infections (OR = 5.0, chi-square 10.4, P < (0.0001). Similar associations were not observed for diarrhea. Controlling for earlier RTI, lower maternal intakes of vitamin A or C and animal source energy, protein, riboflavin, zinc or calcium were associated with more days sick with RTI in infants during 3-6 months whereas lower birth weight was associated with a longer duration. Among the variables examined poor household sanitation was the only significant predictor of diarrheal illnesses in this population. CONCLUSIONS: Infants living in unsanitary households were the main victims of diarrhea. Duration of RTI was shorter for infants of higher birth weight and sick days were fewer for infants whose mothers consumed more animal source foods, vitamin A or vitamin C.

PIP: In a longitudinal household-based study of infant morbidity from birth to 6 months of age in the village of Kalama, Egypt, morbidity information was obtained for 119 singleton infants from 131 mothers; 80 had longitudinal records and more than 120 days of morbidity recall during the first 6 months of age. Birth weights were normally distributed and the mean was comparable to the National Center for Health Statistics reference median. Most infants experienced growth faltering and increased illness episodes during 3-6 months of age. Infants with respiratory tract infections (RTI) during the first 3-month period were at a significantly higher risk of developing subsequent RTI compared with infants without earlier infections (OR = 5.0, chi-square 10.4, p 0.0001). Similar associations were not observed for diarrhea. A combination of household and maternal variables were tested by multiple regression analysis in 2 samples of 74 and 65 infants, respectively. Poor household sanitation was the only significant predictor of diarrheal illnesses. Controlling for earlier RTI, lower maternal intakes of vitamin A or C and animal source energy, protein, riboflavin, zinc or calcium were associated with more days sick with RTI in infants during 3-6 months, whereas lower birth weight was associated with a longer duration. Among all the illness during the first 6 months of age the most frequent episodes of illness were RTI (39%) and diarrhea (31%), followed by eye infections (18%) and skin conditions (6%). Among the 80 infants 27 (34%) experienced diarrhea during 0-3 months of age and the mean percentage time of being sick was 9.2%; during the second 3 months, 40 infants (50%) were sick 121% of the time. Infants were sick more often with RTI than with diarrhea during both of these periods. RTI episodes were longer during the first 3 months than during the second 3 months.

The significance of children's age in estimating the effect of maternal time use on children's well-being.

The women's initiative launched by the United Nations Decade for Women has sparked unresolved controversy over the consequences of mothers' increased participation in economically productive activities on children's well-being. Clearly, in many developing countries, poor mothers face stringent time constraints requiring trade-offs in time allocated to various activities, including child caregiving. However, the impact of these trade-offs on children's well-being remains unclear. The effect of maternal time use on children's nutrition and health status requires more rigorous examination. In particular, the role of children's age in this relationship is critical. Although children's requirement for maternal care varies with factors such as their age (a proxy for stage of psychobiological and sociocultural development), season of year and family size and structure, children's age has not been highlighted in the debate or in the relevant research. This paper documents children's age as a critical factor in the relationship between maternal patterns of time use and the well-being of children 18-30 months of age in peri-urban Egypt. It describes differences in maternal patterns of daily time use according to children's age and illustrates the differential associations between maternal daily activity patterns and children's well-being by children's age. Quantitative data collected on 161 mother-toddler pairs included information on maternal daily time allocation, children's dietary energy intake and diarrheal morbidity, maternal hemoglobin, and household and individual sociodemographics. Data were stratified by children's age at 24 months and were analyzed cross-sectionally using multiple linear and logistic regression. Results indicated that the age of two is critical in Kalama. At this age, toddlers begin to receive less time-intensive care freeing mothers for economic and self production. With respect to children's well-being prior to age two, frequency of feeding was positively related to their energy intake and more time spent in household sanitation activities reduced children's risk of diarrhea (during the diarrhea season). After two years of age, the maternal behaviors measured did not affect children's energy intake; however, children's diarrheal risk was reduced (during the diarrhea season) when mothers held them more and allocated more time to household sanitation year-round. We recommend that other investigators carefully examine the relationships between children's well-being according to developmentally-defined child age intervals and maternal patterns of time use. Results will help to resolve concern over the effect of maternal participation in economically productive activities on children's well-being.

Vitamin B-6 adequacy in neonatal nutrition: associations with preterm delivery, type of feeding, and vitamin B-6 supplementation.

Concerns about vitamin B-6 adequacy in neonatal nutrition relate to critical functions of the vitamin in development. Vitamin B-6 status was assessed in six groups of neonates: two groups each of breast-fed term and preterm infants whose mothers were supplemented with 2 or 27 mg pyridoxine-hydrochloride (PN-HCl); a subgroup of term infants (2-mg maternal group) supplemented with 0.4 mg PN-HCl/d; and a formula-fed preterm group. During the 28-d experimental period, weekly assessments showed lower concentrations of total vitamin B-6 and percentages of pyridoxal in milk from mothers of preterm infants than in milk from mothers of term infants, even when maternal PN-HCl supplementation was 27 mg/d. The vitamin B-6 concentration of milk and estimated intakes of the vitamin by breast-fed infants paralleled maternal supplements (ie, 2 and 27 mg). Plasma and erythrocyte measurements of infants correlated with their vitamin B-6 intakes; values were highest for infants given vitamin B-6 supplements and those that wee formula-fed. Vitamin B-6 adequacy was questionable for unsupplemented breast-fed infants of mothers in the 2-mg supplemented groups.

Relation of maternal zinc nutriture to pregnancy outcome and infant development in an Egyptian village.

Zinc nutriture of women living in a periurban Egyptian village was examined over the last 6 mo of pregnancy and the first 6 mo of lactation as one of several potential determinants of pregnancy outcome and infant development. Estimated bioavailable zinc intake was approximately 2 mg/d from diets high in phytate and fiber. Among numerous variables analyzed by multiple regression, early pregnancy weight (3 mo) and plasma zinc concentrations in the second trimester formed the best predictor model of birth weight, accounting for 39% of the variance. Bioavailable zinc intake during pregnancy was part of a profile of micronutrient intakes related to neonatal habituation behavior, a measure of early information processing. Performance on the Bayley motor test at 6 mo of age was negatively related to maternal intakes of plant zinc, phytate, and fiber, suggesting that zinc bioavailability was involved. Maternal dietary intake explained most of the variance observed in infant motor performance; however, predictive variance was amplified by the psychosocial context.

Maternal body mass index and pregnancy outcome in the Nutrition Collaborative Research Support Program.

This paper uses data from the Nutrition CRSP in Egypt, Mexico and Kenya to examine relationships between maternal BMI and pregnancy outcome. Women were studied from the periconceptional period up to 6 months of lactation. No women in Egypt or Mexico, and only two in Kenya where periods of food shortage occurred, had a BMI < 18 at conception. Women with a lower BMI in Mexico and Kenya gained more weight and fat in pregnancy and lost more weight and fat during lactation. These counter-intuitive relationships affect the interpretation of weight and body composition measures used to assess energy adequacy during pregnancy and lactation. Lower pre-pregnancy BMI predicted lower infant weights at birth and was a risk factor for low birthweight in Kenya. At 3-6 months post partum, maternal BMI was less strongly related to infant size, and the lean body mass component of BMI appeared to be a more important predictor than fatness.

Relations between nutrition and cognitive performance in Egyptian toddlers.

PIP: Two relatively unexplored questions--which specific components of chronic mild child malnutrition are associated with specific behavioral and cognitive deficits and do psychosocial child rearing factors moderate the nutrition-development relationship?--were investigated in a longitudinal study involving 153 toddlers from the Egyptian village of Kalama. Beginning at study entry at age 18 months and continuing until 30 months, food intake information was obtained for 2 consecutive days each month. During the same period, researchers visited the homes twice a month to observe both toddler behavior and caregiver styles. Finally, standardized infant development tests were administered at 24 months and 30 minutes and the capacity for exploratory, symbolic play was assessed. Specific components of nutritional intake at 18-23 months of age were confirmed to be uniquely related to specific developmental outcomes at 24 months of age. Changes in toddler intake from 18-30 months also predicted 30-month cognitive performance. At 24 months, general mental competence was associated positively with fat intake, total kilocalories, and total protein intake while symbolic play capacity was related only to total protein intake. Significant increases in predictive variance occurred when the model was expanded to encompass caregiver behaviors as well as nutritional factors. For example, when nonverbal response to child vocalizations was used as the environmental measure, there was evidence of both coactive and synergistic interactions for comparisons involving cognitive development indicators. For symbolic play, an increase in predictive variance was found when the model included the multiplicative interaction of animal kilocalories by nonverbal response to vocalizations. Also observed was a buffering effect against poor psychosocial rearing conditions given the presence of adequate nutritional intake. These findings suggest the feasibility of multidimensional risk profiles, the provision of specific nutrients targeted at specific deficits, and multidisciplinary interventions.^ieng

Diet during lactation associated with infant behavior and caregiver-infant interaction in a semirural Egyptian village.

Potential processes through which nutritional and non-nutritional factors can relate to infant state and behavior and mother-infant interactions were examined in 41 mother-infant pairs from semirural Egyptian households. All infants were breast-fed, and breast milk was the main source of their nutrient intake. Median birth weight was close to reference median; however, most infants showed growth faltering when they were 3-6 mo of age. Among the infant behavioral and state variables, only drowsiness (a proxy for activity and alertness) was significantly associated with the nutritional and non-nutritional factors examined. Among these factors, mothers' intakes of animal source foods and certain B vitamins were the strongest predictors of drowsiness. The nature of the association between maternal diet and drowsiness, examined by multiple regression analysis, showed clearly that inadequate diet of the mother was the major risk factor. Alertness of infants was further compromised when there were several children in the households. The small, less vocal and less alert infants received less vocalization from their mothers. In this environment, infants of undernourished mothers may not receive the extra care and stimulation needed and are at risk for subsequent developmental disabilities.

PIP: Each week physicians visited the households of 41 mother-infant pairs living in Kalama, Egypt, to examine infant behavior and caregiver-infant interactions from 3 to 6 months of age, as they relate to various factors, e.g., maternal nutrition and health and socioeconomic status. All the mothers breast fed their infants. Liquids which are inferior sources of energy and nutrients were the most customary food supplements during the first 6 months. Even though the median birth weight tended to equal that of the WHO international reference, most infants experienced faltering growth by 3 months. At 6 months, 75% were below the 25th percentile and 20% were in the 5th percentile. Growth faltering was linked with increased diarrhea (p .05). Even though the mothers' diets contained sufficient niacin, thiamin, folate, and vitamin C, the diets did not supply mothers enough riboflavin, vitamin B-6, vitamin A, calcium, and zinc. Breast milk did not have adequate amounts of vitamin B-6 and, perhaps, not even enough riboflavin and vitamin A. It did contain adequate amounts of calcium, however. Drowsiness was significantly related to maternal diet during lactation but not during pregnancy (especially energy intake from animal sources, p = .0001; energy intake from plant sources, p = .03); number of siblings (p = .009); crowding (p = .06); vocalization from mothers (p = .08); and low socioeconomic status (p = .07). Maternal diet was the best predictor of drowsiness followed by number of siblings. Without remediation in maternal nutrition, infants of undernourished mothers appeared not to receive appropriate care and stimulation, therefore placing them at risk of subsequent development disabilities. Intervention studies should be done to examine this main effect of maternal undernutrition and the importance of covarying environmental risk factors, e.g., crowding.

Vitamin B-6 status of breast-fed neonates: influence of pyridoxine supplementation on mothers and neonates.

Vitamin B-6 concentrations in human milk are known to respond rapidly to changes in maternal vitamin B-6 intake. In this study, mothers were supplemented during the first 28 d of lactation with 2 or 27 mg pyridoxine (PN)-HCl/d and a subgroup of breast-fed infants of the 2-mg/d-supplemented mothers were supplemented with 0.4 mg PN-HCl/d. Vitamin B-6 intakes of breast-fed infants reflected the amount of their mother's supplement; intakes were highest for the vitamin-supplemented infants. Vitamin B-6 intake of mothers was a strong indicator of infant vitamin B-6 status. Vitamin intake of infants correlated significantly with five measures of vitamin B-6 status. Plasma pyridoxal-5'-phosphate (PLP) concentrations and birth weight were the strongest predictors of infant growth that were examined. Alkaline phosphatase activity in the mother's milk and infant plasma reflected pyridoxal-PLP ratios in these fluids, suggesting that the enzyme acts in regulating circulating vitamer concentrations.

Relation of short-term pyridoxine-HCl supplementation to plasma vitamin B-6 vitamers and amino acid concentrations in young women.

Pyridoxal 5'-phosphate (PLP) is a coenzyme in many metabolic transformations of amino acids and may play a role in their absorption and transport. This investigation analyzed the effects of large oral doses (27 mg/d) of pyridoxine (PN)-HCl over 2 wk on plasma PLP and amino acid concentrations in 10 young women. Plasma PLP was 45 +/- 2 nmol/L (means +/- SE) initially and reached 377 +/- 12 nmol/L after 7 d of supplementation. A steady-state PLP concentration remained as long as daily PN-HCl supplementation was continued. Plasma glutamic acid concentration was significantly lower after 7 and 14 d of supplementation whereas alpha-amino-N-butyric acid, alanine, cysteine, arginine, phosphoserine, and urea concentrations were significantly higher, particularly alpha-amino-N-butyric acid and cysteine. Altered plasma amino acid profiles and increased plasma urea concentrations in response to supplementation suggested accelerated protein and/or amino acid metabolism.

Determinants of pregnancy outcome and newborn behavior of a semirural Egyptian population.

Several potential determinants of birth weight and neonatal behavioral organization, ie, maternal anthropometry, food intake (energy, protein, and plant- and animal-source foods), morbidity, and household socioeconomic status, were followed systematically in a semirural Egyptian population during greater than or equal to 6 mo of pregnancy. In early pregnancy mothers were generally normal weight to moderately overweight. Their mean energy intake, largely from plant sources, was approximately 8.37 MJ/d (2000 kcal/d) during trimesters 2 and 3. Early (3 mo) pregnancy weight and weight gain during trimesters 2 and 3 were significantly positively related to birth weight Z scores. The best predictor model examined for birth weight included early pregnancy weight, weight gain, and length of gestation (R2 = 0.45). Early pregnancy weight and maternal intake of animal-source foods were significant positive predictors of the newborn's orientation and habituation behavior, respectively. Habituation and orientation measures assess the infant's early ability to process information.

Distribution of B-6 vitamers in human milk during a 24-h period after oral supplementation with different amounts of pyridoxine.

The relative distribution of B-6 vitamers, separated by reverse-phase liquid chromatography, was examined in human milk during a 24-h period after supplementation with 2.5 or 15 mg pyridoxine hydrochloride. Consistently, pyridoxal (PL) was the predominate vitamer and the most responsive to vitamin B-6 intake. During 3-8 h after supplement ingestion, PL, pyridoxal phosphate, and pyridoxamine concentrations were significantly higher than at other times examined. In the first two periods after supplementation, PL as a percentage of total vitamin B-6 was slightly but significantly higher in milk from the group supplemented with 15 mg than from the group supplemented with 2.5 mg. With the exception of PL, the distribution of B-6 vitamers, expressed as percent of total vitamin B-6, was similar for the two supplemented groups at all times examined. Percentage PL of total vitamin B-6 in milk was approximately 25% lower in unsupplemented than in supplemented women.

Vitamin B-6 status of Egyptian mothers: relation to infant behavior and maternal-infant interactions.

Functional consequences of marginal maternal vitamin B-6 status for behavior of the neonate and for mother-infant interactions at age 3-6 mo were assessed by a double-blind procedure. In 27 of 70 Egyptian village women studied, vitamin B-6 concentration of their milk was considered indicative of poor maternal vitamin B-6 nutriture. Neonatal behavior, quantified by the Brazelton Neonatal Behavioral Assessment Scale, showed that consolability, appropriate build-up to a crying state, and response to aversive stimuli were significantly correlated with maternal vitamin B-6 nutriture. Naturalistic observational procedures, used twice monthly with infants aged 3-6 mo, indicated that mothers assessed as having marginal vitamin B-6 status were less responsive to their infants' vocalizations, showed less effective intervention to infant distress, and were more likely to use older siblings as care-givers than were mothers of better vitamin status. We conclude that vitamin B-6 was a factor influencing both the behavior of the mother and her infant.

Pyridoxine supplementation of lactating mothers: relation to maternal nutrition status and vitamin B-6 concentrations in milk.

Vitamin B-6 status, assessed by plasma pyridoxal phosphate (PLP) concentrations, and vitamin B-6 concentrations in breast milk were examined in 47 lactating mothers supplemented with different amounts of pyridoxine.HCl (PN.HCl) during pregnancy and the first 6 mo of lactation. PLP concentrations in cord blood and maternal plasma at 2 d postpartum and vitamin B-6 concentration in colostrum were positively correlated with the amount of PN.HCl supplementation prenatally (r = 0.71, p less than 0.001; r = 0.74, p less than 0.001; and r = 0.78, p less than 0.001, respectively). Correlations between the amounts of PN.HCl supplementation postnatally and plasma PLP concentrations increased with the length of supplementation. Plasma PLP concentrations were also correlated with vitamin B-6 concentrations of milk samples, which were obtained on the same day as plasma. PN.HCl supplements between 2.5 and 4.0 mg/d (2.1-3.4 mg PN equivalents) ensured vitamin B-6 adequacy of the mother and maintained relatively saturated concentrations of vitamin B-6 in breast milk.

Effects of maternal restriction in vitamin B-6 on neocortex development in rats: neuron differentiation and synaptogenesis.

Effects of maternal restrictions in vitamin B-6 on neuron differentiation and synaptogenesis in developing neocortex were examined. Rats were fed ad libitum a vitamin B-6-free diet supplemented with 0.0 or 0.6 mg pyridoxine hydrochloride (PN.HCl)/kg diet during gestation followed by a control level of 7.0 mg/kg diet during lactation, or they were fed the vitamin B-6-free diet supplemented with 0.6 or 7.0 mg PN.HCl/kg diet throughout gestation and lactation. Neocortices of the offspring were examined at 30 d of age by light and electron microscopy. All maternal restrictions in vitamin B-6 reduced the number of higher order dendrites on stellate neurons in layer II and on pyramidal neurons in layer V of the neocortex and decreased synaptic density in the neuropil of the neocortex. The findings indicated that vitamin B-6 restriction during gestation, either marginal or severe, was the critical treatment factor that adversely affected synaptogenesis and at least one event in neuron differentiation in the neocortex, the arborization of dendrites.

Neuronal development in vitamin B6 deficiency.

The morphological changes observed in developing brain regions associated with maternal vitamin B6 deficits are summarized in Table 4. Brain development is a complex and orderly process consisting of cell division, proliferation, migration, and maturation. In the rat, vitamin B6 deficits imposed in utero and up to 30 days postnatal interfere with this orderly process. Deficits of the vitamin imposed in utero have been associated with reduced numbers of total and normal neurons in neocortex and with increased shrunken neurons (700-1500% of controls) in this region. These changes reflect the critical role of vitamin B6 in both neurogenesis and neuron longevity in neocortex. Postnatal cellular events in the neocortex, that is, neuron differentiation and synaptogenesis, were also altered by vitamin B6 deficits; higher order dendrites were reduced on stellate neurons in Layer II and on pyramidal neurons in Layer V. Synaptic density was less in the neutrophil of neocortex and in caudate/putamen, but structural integrity of the synapse was maintained. In cerebellum, both the molecular and granular areas were reduced, the monolayer organization of Purkinje cells was disrupted, and dendritic arborization of the cells was decreased. The number of myelinated axons, as determined by electron microscopy, was decreased in the mediodorsal portion of the pyramidal tract in the medulla oblongata as well as the specific activity of myelination of the total brain. Thus the functional consequences of vitamin B6 deficits during neuronal development may be through reduced connections among neurons and decreased myelination, which alter the rate and magnitude of transmission of nerve impulses.

Zinc, calcium, and magnesium concentrations in milk from American and Egyptian women throughout the first 6 months of lactation.

Effects of stage of lactation, nutrient intake, and cultural differences on the composition of human milk were examined during the first 6 mo of lactation in American and Egyptian women. In both population groups zinc levels in milk decreased from 1 to 6 months of lactation. American women supplemented with Zn had higher levels of Zn in their milk than did unsupplemented American or Egyptian women. Concentrations of calcium and magnesium were not significantly different in milk of American and Egyptian women except at month 6 of lactation. Ca levels in milk of both population groups increased from 1 to 2-3 mo of lactation and then decreased at 6 mo; Mg concentrations increased from 1 to 3 mo and then reached a plateau. Similarities in the longitudinal decrease observed in Zn levels of milk in Zn supplemented and unsupplemented subjects suggested physiological regulation.