Iron supplementation of breast-fed Honduran and Swedish infants from 4 to 9 months of age.

OBJECTIVE: The objective was to study the effects of iron supplementation on hemoglobin and iron status in 2 different populations. STUDY DESIGN: In a randomized, placebo-controlled, masked clinical trial, we assigned term Swedish (n = 101) and Honduran (n = 131) infants to 3 groups at 4 months of age: (1) iron supplements, 1 mg/kg/d, from 4 to 9 months, (2) placebo, 4 to 6 months and iron, 6 to 9 months, and (3) placebo, 4 to 9 months. All infants were breast-fed exclusively to 6 months and partially to 9 months. RESULTS: From 4 to 6 months, the effect of iron (group 1 vs 2 + 3) was significant and similar in both populations for hemoglobin, ferritin, and zinc protoporphyrin. From 6 to 9 months, the effect (group 2 vs group 3) was significant and similar at both sites for all iron status variables except hemoglobin, for which there was a significant effect only in Honduras. In Honduras, the prevalence of iron deficiency anemia at 9 months was 29% in the placebo group and 9% in the supplemented groups. In Sweden, iron supplements caused no reduction in the already low prevalence of iron deficiency anemia at 9 months (<3%). CONCLUSION: Iron supplementation from 4 to 9 months or 6 to 9 months significantly reduced iron deficiency anemia in Honduran breast-fed infants. The unexpected hemoglobin response at 4 to 6 months in both populations suggests that regulation of hemoglobin synthesis is immature at this age.

Effects of exclusive breastfeeding for four versus six months on maternal nutritional status and infant motor development: results of two randomized trials in Honduras.

To examine whether the duration of exclusive breastfeeding affects maternal nutrition or infant motor development, we examined data from two studies in Honduras: the first with 141 infants of low-income primiparous women and the second with 119 term, low birth weight infants. In both studies, infants were exclusively breastfed for 4 mo and then randomly assigned to continue exclusive breastfeeding (EBF) until 6 mo or to receive high-quality, hygienic solid foods (SF) in addition to breast milk between 4 and 6 mo. Maternal weight loss between 4 and 6 mo was significantly greater in the exclusive breastfeeding group (EBF) group than in the group(s) given solid foods (SF) in study 1 (-0.7 +/- 1.5 versus -0.1 +/- 1.7 kg, P < 0.05) but not in study 2. The estimated average additional nutritional burden of continuing to exclusively breastfeed until 6 mo was small, representing only 0.1-6.0% of the recommended dietary allowance for energy, vitamin A, calcium and iron. Women in the EBF group were more likely to be amenorrheic at 6 mo than women in the SF group, which conserves nutrients such as iron. In both studies, few women (10-11%) were thin (body mass index <19 kg/m(2)), so the additional weight loss in the EBF group in study 1 was unlikely to have been detrimental. Infants in the EBF group crawled sooner (both studies) and were more likely to be walking by 12 mo (study 1) than infants in the SF group. Taken together with our previous findings, these results indicate that the advantages of exclusive breastfeeding during this interval appear to outweigh any potential disadvantages in this setting.

Promoting exclusive breastfeeding for 4-6 months in Honduras: attitudes of mothers and barriers to compliance.

Prospective and retrospective data on maternal attitudes and obstacles to exclusive breastfeeding (EBF) were collected from Honduran mothers of low birthweight (1500-2500 g), term infants who were enrolled in an intervention study to compare infant outcomes in those who were randomly assigned to breastfeed exclusively for either 4 or 6 months. Perceived advantages of EBF were that it was easier, more practical and economical, and resulted in better infant health and growth. Disadvantages included the perceived time demand, concerns that the infant would accept solids less readily, and fears that breast milk alone was insufficient. The majority of study participants said that they would choose to exclusively breastfeed their next infant to 6 months. Although there were many obstacles to EBF, particularly in the first few weeks, women who persevered became enthusiastic proponents of EBF. Messages to promote EBF need to target the entire community, not just mothers, and should focus on addressing common misconceptions and alerting women to potential problems before they occur.

Precision, accuracy, and reliability of hemoglobin assessment with use of capillary blood.

BACKGROUND: Previous research has suggested that there may be significant within-subject variability, both site-to-site and over time, in hemoglobin concentrations in capillary blood. OBJECTIVE: This study examined the reliability of the portable hemoglobinometer (PHM) system with use of capillary blood and the implications of errors of the magnitude found for the classification of anemia status in individuals and population groups. The precision and accuracy of the method with use of venous blood were also tested. DESIGN: Three empirical data sets were used to measure reliability, precision, and accuracy of the PHM system [2 from Honduras (n = 87 and 141); 1 from Bangladesh (n = 73)]. Simulation data were used to assess the implications of errors for screening individuals for anemia and to estimate anemia prevalence. RESULTS: High within-subject variability (unreliability) was identified when capillary blood from the left hand was compared with that from the right hand (CV: 6.3%) and when measurements were taken on 4 consecutive days (CV: 7.0%). Reliability was only 69% and 50%, respectively. Precision and accuracy, however, were very high (concordance coefficients of 0.99 and 0.98 and CV < 1%). CONCLUSIONS: The simulation data showed that errors of the magnitude found due to unreliability can lead to misclassification of anemia status in individuals and small biases in anemia prevalence estimates. We recommend replicate sampling to reduce the influence of unreliability in the use of the PHM system with capillary blood.

Age of introduction of complementary foods and growth of term, low-birth-weight, breast-fed infants: a randomized intervention study in Honduras.

BACKGROUND: The optimal age at which to introduce complementary foods is a topic of considerable debate. OBJECTIVE: This study was designed to evaluate this issue in a nutritionally vulnerable population in Honduras. DESIGN: Mothers of low-birth-weight (1500-2500 g) term (ie, small-for-gestational-age) infants were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo. At 4 mo, mothers were randomly assigned to either continue exclusive breast-feeding to 6 mo (EBF; n = 59) or to feed complementary solid foods (jarred rice cereal, chicken, and fruit and vegetables) twice daily from 4 to 6 mo while continuing to breast-feed at their initial frequency (SF; n = 60). At 4 and 6 mo, breast milk and total energy intake were measured for a nonrandom subsample (those who could stay overnight in a central unit: 32 EBF and 31 SF). RESULTS: At 4 mo, breast milk intake in the subsample was not significantly different between groups (EBF: 729 +/- 135 g/d; SF: 683 +/- 151 g/d: P >0.2); from 4 to 6 mo it increased (by 28 g/d) in the EBF group but decreased (by 39 g/d) in the SF group (P < 0.005). Nonetheless, total energy intake (including solid foods) increased more from 4 to 6 mo in the SF than in the EBF group. However, there were no significant differences between groups in weight or length gain during the intervention or subsequently (6-12 mo). CONCLUSION: There was no growth advantage of complementary feeding of small-for-gestational-age, breast-fed infants between 4 and 6 mo of age.

Effects of discontinuing coffee intake on iron deficient Guatemalan toddlers' cognitive development and sleep.

Coffee is commonly given daily to toddlers in Guatemala. Possible negative effects of coffee ingestion on cognitive development and sleep patterns were assessed in 132 children 12-24 months of age who had received coffee for > 2 months and were iron deficient on at least one indicator. Children were stratified by initial hemoglobin (A= anemic, Hgb < 10.5 g/dl; NA = 'non-anemic', Hgb > or = 10.5 g/dl) and were randomly assigned to an experimental group (S = substitute consisting of sugar and coloring), and a control group (C = continuation of coffee) (42 C-NA; 53 S-NA; 18 C-A; and 19 S-A). Anemic children were provided Fe supplements for 2-3 months. Compliance was assessed every 2 weeks. After 5 months, testers masked to treatment group and anemia evaluated children with the Bayley Scales of Infant Development II in a central location. Scores were the Mental Development Index (MDI), the Psychomotor Development Index (PDI), and scales from the Behavior Rating Scale (BRS). The child's sleep in the previous 24 h was assessed with a set of standardized sleep questions to the care giver on the first visit and every 2 weeks thereafter. No significant effects of treatment on test scores or BRS ratings were found. In the 24 h period reported on at the final visit, children in the Substitute group slept more during the night and overall (night plus naps) than children in the Coffee group, a difference not found at the first visit. No differences were found in sleep difficulty or number of times waking at night. Women's reported coffee intake per day during pregnancy was associated with lower BRS ratings, even after controlling for SES and child age. The effects of postnatal coffee ingestion in Guatemala were seen for sleep duration, but not for cognitive development. Prenatal coffee ingestion was negatively associated with Behavior Rating Scales and should be investigated further.

Weight change during lactation does not alter the concentrations of chlorinated organic contaminants in breast milk of women with low exposure.

The purpose of this longitudinal study was to evaluate whether a loss of body fat during lactation between 4 and 20 wk postpartum increases the concentration of environmental contaminants in breast milk. We examined this relationship in two different cohorts of exclusively breastfeeding women: (1) California women with low exposure to contaminants (n = 10 whose weight was stable [mean change, 0.0 +/- 0.2 kg] and n = 11 who lost weight [mean loss, -4.1 +/- 0.4 kg]) and (2) Hispanic women (n = 30) who had recently immigrated to North Carolina, primarily from Mexico, and were presumed to have a higher prior exposure to contaminants. Breast milk samples were analyzed for hexachlorobenzene (HCB) and DDT and its related products. There was no significant relationship between change in body composition and change in milk contaminant concentrations in either California or North Carolina women. Concentrations of HCB were similar between the California and North Carolina women, but those of DDT and related products were higher in the North Carolina subjects. Results suggest that moderate weight loss in lactating women with low exposure to environmental contaminants does not increase contaminant concentration in breast milk.

Effects of age of introduction of complementary foods on iron status of breast-fed infants in Honduras.

To evaluate the effect of introducing complementary foods before 6 mo of age, we randomly assigned 164 infants who had been exclusively breast-fed for 4 mo to continue being exclusively breast-fed until 6 mo (EBF group) or to receive iron-fortified foods in addition to breast milk from 4 to 6 mo (BF+SF group). At 6 mo, the BF+SF group had higher mean iron intake (4 mg/d compared with 0.2 mg/d in EBF infants) and higher hemoglobin, hematocrit, and ferritin values than the EBF group (P < 0.05). The percentage with low hemoglobin (< 103 g/L) did not differ significantly between groups, but fewer infants in the BF+SF group had a low hematocrit (< 0.33; 21.4% compared with 32.0%, respectively; P < 0.05). The percentage of infants with ferritin concentrations < 12 microg/L at 6 mo was lower than the percentage with low hemoglobin or hematocrit, raising questions about the validity of the cutoffs at this age. Infants at greatest risk for anemia and low ferritin were those with birth weights < 2500 g; no infant with a birth weight > 3000 g had a low ferritin value at 6 mo. We conclude that the risk of iron deficiency is low among infants with birth weights > 3000 g who are exclusively breast-fed for 6 mo. Iron drops are recommended for low-birth-weight infants; for breast-fed infants with birth weights between 2500 and 3000 g, further research is needed to determine whether iron drops are more effective than complementary foods for preventing iron deficiency before 6 mo.

Cross-cultural patterns of growth and nutritional status of breast-fed infants.

Growth patterns and iron status of infants who were breast-fed throughout their first year of life were examined in four populations: 1) a group of high socioeconomic status in California (the DARLING Study), 2) infants of normal birth weight (NBW) but from low-income families in Honduras, 3) low-birth-weight (LBW), full-term infants in Honduras, and 4) infants in Ghana. z Scores were calculated by using both the current National Center for Health Statistics reference data and a pooled data set based on breast-fed infants in six industrialized countries. The NBW infants in Honduras showed rapid growth in the first few months and were similar in weight-for-age to the DARLING infants until approximately 9 mo. By contrast, the LBW infants remained far below the other cohorts throughout the first 12 mo, despite an initial period of catch-up growth. In the Ghanaian infants, weight-for-age faltered beginning at 3-4 mo, but length-for-age did not falter until after 9 mo. Weight-for-length was highest in the NBW Honduran infants and lowest in the Ghanaian infants. When z scores were adjusted for birth weight and maternal height, no significant faltering was evident in either weight or length in any of the cohorts during the first 12 mo. Thus, when breast-feeding is continued during the first year of life and efforts are made to ensure adequate complementary feeding after 6 mo, if growth faltering occurs it is probably attributable to prenatal factors and maternal stature. Population differences in iron status reflected variation in birth weight and in the use of iron-rich foods. Therefore, efforts to prevent child stunting and malnutrition must pay attention to prenatal as well as postnatal factors.

Effects of discontinuing coffee intake on iron status of iron-deficient Guatemalan toddlers: a randomized intervention study.

Coffee is one of the first liquids given to infants in Guatemala. To evaluate whether this practice has an adverse effect on iron status, 160 children 12-24 mo of age who had received coffee for > or = 2 mo and had at least one indicator of iron deficiency were stratified by initial hemoglobin concentration (anemic, or nonanemic, ie, hemoglobin > or = 105 g/L) and randomly assigned to a control (continuation of coffee; coffee) or intervention (provided with a substitute consisting of sugar and coloring; substitute) group for 5 mo. Anemic children were provided with iron supplements for 2-3 mo. Hematologic and anthropometric measurements were made before and after the intervention and dietary and morbidity data were collected every 2 wk. A total of 139 children completed the study: 45 coffee, nonanemic; 56 substitute, nonanemic; 19 coffee, anemic; and 19 substitute, anemic. Compliance with the procedures was good: median coffee intake was 891 mL/wk in the coffee group compared with 18 mL/wk in the substitute group (P = 0.0001). There was no significant effect of discontinuing coffee consumption on changes in hemoglobin, hematocrit, ratio of zinc protoporphyrin to heme or plasma iron, zinc or copper in either nonanemic or anemic children, or plasma ferritin in children who did not take iron supplements. In children who took iron supplements, change in plasma ferritin was significantly greater in the substitute group than in the coffee group (106% compared with 1%, P < 0.05). This implies that coffee interferes with the utilization of supplemental iron. It is likely that the amount and strength of coffee consumed by Guatemalan toddlers are too low to significantly affect the other indexes of iron status.

Effects of age at introduction of complementary foods to breast-fed infants on duration of lactational amenorrhea in Honduran women.

Lactational amenorrhea (LA) is associated with postpartum infertility and is known to be related to breast-feeding frequency and duration, but the exact role of complementary feeding of the infant has not been clearly defined. Data on LA were collected during and after a 2-mo intervention trial in which low-income Honduran women who had breast-fed fully for 4 mo were randomly assigned to one of three groups: continued full breast-feeding until 6 mo (FBF, n = 50), introduction of complementary foods at 4 mo with ad libitum breast-feeding from 4 to 6 mo (SF, n = 47), or introduction of complementary foods at 4 mo with maintenance of baseline breast-feeding frequency from 4 to 6 mo (SF-M, n = 44). Women were followed up until the infant was 12 mo of age, or later if menses had not occurred by then. All but six of the women continued to breast-feed for > or = 12 mo. With the exclusion of those whose menses returned before 18 wk postpartum (which could not have been due to the intervention), the proportion of women who were amenorrheic at 6 mo was 64.5% in the SF group, 80.0% in the FBF group, and 85.7% in the SF-M group (chi-square test = 4.13, P = 0.02; one-tailed test with the latter two groups combined). The total duration of LA did not differ significantly among groups. The most significant determinant of LA was time spent breast-feeding (min/d), which was in turn negatively associated (P = 0.06) with the infant's energy intake from complementary foods in regression analyses. These results indicate that there is a significant effect of introducing foods at 4 mo on the likelihood of amenorrhea at 6 mo postpartum, but not thereafter, and that this effect is not seen in mothers who maintain breast-feeding frequency.

A randomized intervention study of the effects of discontinuing coffee intake on growth and morbidity of iron-deficient Guatemalan toddlers.

Coffee is widely consumed by children in Guatemala. To evaluate whether coffee has an adverse effect on growth or morbidity, 160 children 12-24 mo of age who had received coffee for > or = 2 mo and had at least one indicator of iron deficiency were stratified by initial hemoglobin (Hb) (A = anemic vs. NA = "nonanemic", i.e., Hb > or = 105 g/L) and randomly assigned to a control (C = continuation of coffee) or intervention group (S = provided with a substitute consisting of sugar and coloring) for 5 mo. Anemic children were provided iron supplements for 2-3 mo. Hematological and anthropometric measurements were made before and after the intervention, and dietary and morbidity data were collected every 2 wk. A total of 139 children completed the intervention: 45 C-NA, 56 S-NA, 19 C-A and 19 S-A. Compliance with the intervention was good: median coffee intake was 127 mL/d in group C vs. 3 mL/d in group S (P = 0.0001). There were no significant differences between C vs. S groups in food intake before or after the intervention. In the total sample, there was no effect of the intervention on weight or length gain. However, in children initially consuming more than 100 mL/d of coffee (n = 96), length gain was 22% greater in the S vs. the C group (P = 0.07), and weight gain was 46% greater in the S-A vs. the C-A group (P < 0.05; NS in the NA groups). Total illness prevalence (particularly respiratory illness) was significantly lower in the S-NA vs. the C-NA group (P < 0.05), but somewhat higher in the S-A vs. the C-A group (P = 0.09). Morbidity differences did not explain the effect of the intervention on growth. These results indicate a modest increase in growth associated with discontinuation of coffee consumption by toddlers with initial intakes >100 mL/d.

PIP: Coffee intake has been associated with several adverse nutritional consequences in both animal models and human studies. Accordingly, in North America, coffee is not thought to be an appropriate beverage for children. In contrast, coffee is widely consumed among children in Guatemala and is even one of the first liquids given to infants, beginning as early as 2 months of age. A study investigated whether coffee has an adverse effect upon child growth or morbidity. 160 children of age 12-24 months who had received coffee for 2 or more months and had at least one indicator of iron deficiency were stratified by initial hemoglobin and randomly assigned to the control or intervention group for 5 months. Children in the control group continued to receive coffee, while children in the intervention group were instead given a substitute consisting of sugar and coloring. Anemic children were provided iron supplements for 2-3 months. Hematological and anthropometric measurements were made at baseline and after the intervention, while dietary and morbidity data were collected every 2 weeks. 139 children completed the intervention and compliance was high. No significant difference was found between the control and intervention groups in food intake before or after the intervention. Overall, the intervention had no effect upon weight or length gain. However, a modest increase in growth was associated with the discontinuation of coffee consumption by toddlers with initial intakes of more than 100 ml/day.

Delayed clamping of the umbilical cord improves hematologic status of Guatemalan infants at 2 mo of age.

Iron deficiency anemia is a serious health problem that affects the physical and cognitive development of children. Therefore, it is important to develop cost-effective interventions to improve the hematologic status of the millions of children affected by this condition worldwide. We studied 69 Guatemalan infants who had been randomly assigned to one of three groups at the time of delivery: 1) cord clamping immediately after delivery (n = 21); 2) clamping when the cord stopped pulsating, with the infant placed at the level of the placenta (n = 26); or 3) clamping when the cord stopped pulsating, with the newborn placed below the level of the placenta (n = 22). Maternal and infant hematologic assessments were performed at the time of delivery and 2 mo postpartum. At baseline the groups had similar socioeconomic, demographic, and biomedical characteristics and the newborns had similar hematocrit status. Two months after delivery, infants in the two groups with delayed cord clamping had significantly higher hematocrit values and hemoglobin concentrations than did those in the early-clamping group. The percentage with hematocrit values < 0.33 was 88% in the control group compared with 42% in group 2 and 55% in group 3 (P = 0.01). These results suggest that waiting until the umbilical cord stops pulsating (approximately 1 min after delivery) is a feasible low-cost intervention that can reduce anemia in infants in developing countries.

Validation of single daytime samples of human milk to estimate the 24-h concentration of lipids in urban Guatemalan mothers.

The large within- and between-sample variability in breast milk lipid content greatly complicates the collection of representative samples in field studies. The main purpose of this study was to validate the ability of individual daytime samples to predict the 24-h lipid concentration of breast milk. We also studied maternal, child, and other factors (time of day and interval between feeds) associated with the within- and between-mother variability in milk lipid content. Fifty-two primiparous urban Guatemalan women between 1 and 4 mo postpartum were studied. Milk samples were collected during six 2-h intervals from 0600 to 1800, and throughout the night when the child breast-fed. On average, the 24-h pooled milk samples contained 4.2 +/- 0.92% (mean +/- SD) lipids and the best concordance with this value was obtained with samples collected between 0600 and 0800 (concordance correlation coefficient = 0.60, P < 0.05). None of the regression equations to predict the 24-h lipid content of breast milk based on daytime samples reached a sufficiently high predictive power to be recommended for the estimation of individual child intake. Time of day and time elapsed since the last feeding were significant determinants of diurnal variations in milk lipid content, whereas between-mother variability was explained by maternal weight (P = 0.05) and body mass index (P < 0.05). For the collection of milk samples in surveys and pre-post studies, we recommend standardization of time of day and interval between feeds.

The association between cesarean delivery and breast-feeding outcomes among Mexican women.

OBJECTIVES: This study examined the impact of cesarean section delivery on the initiation and duration of breast-feeding in the 1987 Mexican Demographic and Health Survey. METHODS: The subsample (n = 2517) was restricted to women whose delivery of their last-born children (aged 5 years and younger) was attended by a physician. Multivariate logistic regression was used to examine the association between cesarean section and likelihood of either not initiating breast-feeding or doing so for less than 1 month. Among women who breast-fed for 1 month or more, multivariate survival analysis was used to examine the relationship between cesarean section and breast-feeding duration. RESULTS: Cesarean section was a risk factor for not initiating breast-feeding (odds ratio [OR] = 0.64, 95% confidence interval [CI] = 0.50, 0.82) and for breast feeding for less than 1 month (OR = 0.58, 95% CI = 0.37, 0.91) but was unrelated to breast-feeding duration among women who breast-fed for 1 month or more (OR = 0.97, 95% CI = 0.86, 1.11). CONCLUSIONS: It is desirable to provide additional breast-feeding support during the early postpartum period to women who deliver via cesarean sections.

Delaying the introduction of complementary food until 6 months does not affect appetite or mother's report of food acceptance of breast-fed infants from 6 to 12 months in a low income, Honduran population.

Low income, primiparous mothers who had exclusively breast-fed for 4 mo were randomly assigned to one of three groups: 1) continued exclusive breast-feeding to 6 mo (EBF), 2) introduction of complementary foods at 4 mo, with ad libitum nursing 4-6 mo (SF), and 3) introduction of complementary foods at 4 mo, with maintenance of base-line nursing frequency 4-6 mo (SF-M). After the intervention phase (4-6 mo; n= 141), home visits were conducted for a subsample at 9 (n = 60) and 12 (n = 123) mo. At each visit, an observer recorded infant food intake at the midday meal and interviewed the mother regarding usual feeding patterns and the infant's acceptance of 20 common food items. All but two infants (1.5%) were breast-fed to 9 mo and all but eight (6%) to 12 mo. There were no significant differences among groups in breast-feeding frequency, amount or number of foods consumed at the midday meal, percentage of food offered that was consumed, usual daily number of meals and snacks, number of food groups consumed, or overall food acceptance score. Frequency of consumption of foods from eight different food groups (dairy, meats, eggs, grains, beans, fruits, vegetables, tubers) was not significantly different among groups except that, at 9 mo only, the SF group (but not the SF-M group) consumed more vegetables than did the EBF group. These results indicate that delaying the introduction of complementary foods until 6 mo does not adversely affect appetite or food acceptance among breast-fed infants.

PIP: Low-income primiparous mothers who had breast fed exclusively for 4 months were randomly assigned to one of three groups: 1) continued exclusive breast feeding (EBF) to 6 months; 2) introduction of complementary foods at 4 months with ad libitum nursing 4-6 months (SF); and 3) introduction of complementary foods at 4 months with maintenance of baseline nursing frequency 4-6 months (SF-M). After the intervention phase (4-6 months; n = 141), home visits were conducted for a subsample at 9 (n = 60) and 12 (n = 123) months. At each visit, an observer recorded infant food intake at the midday meal and interviewed the mother regarding usual feeding patterns and the infant's acceptance of 20 common food items. All but two infants (1.5%) were breast fed to 9 months and all but eight (6%) to 12 months. There were no significant differences among groups in breast-feeding frequency, amount or number of foods consumed at the midday meal, percentage of food offered that was consumed, usual daily number of meals and snacks, number of food groups consumed, or overall food acceptance score. Frequency of consumption of foods from eight different food groups (dairy, meats, eggs, grains, beans, fruits, vegetables, tubers) was not significantly different among groups except that, at 9 months only, the SF group (but not the SF-M group) consumed more vegetables than did the EBF group. The SF groups initially accepted carrots more readily than did the other two groups (p .05), and the SF and SF-M groups initially accepted potato more readily than did the EBF group (p .05). The average number of food groups from which foods were consumed at least twice per week was significantly higher in the SF group (but not the Sf-M group) than in EBF group at 9 months, but not at 12 months. Delaying the introduction of complementary foods until 6 months does not adversely affect appetite or food acceptance among breast-fed infants.

Determinants of growth from birth to 12 months among breast-fed Honduran infants in relation to age of introduction of complementary foods.

OBJECTIVES: To evaluate the impact of introducing complementary foods to exclusively breast-fed infants at 4 vs 6 months on growth from 6 to 12 months, and to compare growth patterns of Honduran infants with those of breast-fed infants in the United States. DESIGN: Randomized intervention trial from 4 to 6 months and longitudinal study of infants from birth to 12 months. SETTING: Low-income communities in San Pedro Sula, Honduras. SUBJECTS: Primiparous, breast-feeding mothers and their infants (n = 141) recruited from public maternity hospitals. INTERVENTION: Infants were randomly assigned to exclusive breast-feeding to 6 months, or exclusive breast-feeding with addition of hygienically prepared, nutritionally adequate complementary foods at 4 months, with or without maintenance of baseline breast-feeding frequency. After 6 months, mothers continued to breast-feed and also fed their infants home-prepared foods after receiving instruction in appropriate feeding practices. OUTCOME MEASURES: Infant weight was measured monthly during the first year of life and infant length monthly from 4 to 12 months. STATISTICAL ANALYSIS: Growth parameters were compared between the Honduran and US cohorts using multiple-regression and repeated-measures analysis of variance. Stepwise multiple regression was used to identify determinants of infant growth. RESULTS: There were no differences in growth patterns by intervention group. Mean birth weight of the Honduran infants was significantly less than that of a cohort of breast-fed infants in an affluent US population (n = 46) (2889 +/- 482 vs 3611 +/- 509 g), but the Honduran infants exhibited rapid catch up in weight in the first few months of life, and the cohorts were similar in weight by 3 months. Mean weight and length gain were similar to those of the US cohort from 4 to 9 months but were lower from 9 to 12 months. Mean length for age was significantly less than that of the US cohort from 4 to 12 months; this was attributable to the difference in maternal height (12 cm shorter in Honduras on average). Within the Honduran cohort, growth velocity of low birth weight infants (< 2500 g; n = 28) was similar to that of their normal birth weight peers; thus, the former subgroup remained smaller than the latter throughout the first year of life. CONCLUSIONS: In poor populations, when breast-feeding is exclusive for the first 4 to 6 months, continues from 6 to 12 months, and is accompanied by generally adequate complementary foods, faltering in weight does not occur before 9 months among infants born with birth weights of more than 2500 g.

Maternal activity budgets: feasibility of exclusive breastfeeding for six months among urban women in Honduras.

Although exclusive breastfeeding for 6 months is likely to be beneficial for infant health, mothers often cite time pressures as a reason to introduce other foods. Using 12-hr in-home observations at 19 and 24 wk postpartum, we compared maternal activity budgets and time spent breastfeeding among low-income, urban mothers not employed outside the home who exclusively breastfed (EBF) or gave other foods in addition to breast milk (BF+SF). Breastfeeding time was similar between groups (averaging approx 75 min/12 hr) except that multiparous EBF mothers at 24 wk spent more time breastfeeding their infants than did BF+SF mothers. However, total time devoted to infant feeding (including preparation and feeding of solids in the BF+SF group) was significantly greater in the BF+SF group than in the EBF group (except among multiparous women at 24 wk). Feeding frequency per 12-hr averaged 6.7-8.9 in the EBF group and 5.4-8.1 BF + 1.8 meals in the BF+SF group. Both EBF and BF+SF mothers had considerable 'free' time; they spent, on average, 2-3 hr during each 12-hr period resting, chatting or watching TV. Primiparous women tended to spend less time at household chores and child care than multiparous women. Of the BF+SF mothers, 60% said that breastfeeding was 'somewhat' or 'very' time-demanding (vs 15% of EBF mothers), 49% said that it interfered with other activities (vs 6% of EBF mothers), and 26% said that they gave other foods to extend the time between breastfeeds. Although many of the BF+SF mothers knew that giving foods may increase infant illness, there were cultural pressures not to exclusively breastfeed. For example, many introduced solids to their infants prior to 6 months because they believed that infants should 'learn' how to eat other foods, to 'acclimate' the stomach and learn to differentiate flavors. We conclude that time constraints are not a barrier to exclusive breastfeeding in this population, although they may be perceived as a barrier.

Infant bottle propping among a low-income urban population in Mexico.

The prevalence of bottle propping (permitting an infant to drink from a bottle unattended) and the determinants of this practice at 1 week and 4 months of life were studied in a selected sample of urban women in Hermosillo, Mexico. The sample (n = 165) consisted of mothers planning to breast-feed who gave birth to healthy infants at one of two public hospitals. Data were obtained by interviewing women shortly before they were discharged from the hospital and at about 1 week and 4 months postpartum. Among those mothers giving liquid breast milk substitutes to their infants, the percentage practicing bottle propping increased from 27% at 1 week (n = 20/74) to 67% at 4 months (n = 87/130). Women who practiced bottle propping at 1 week were significantly more likely to continue this practice at 4 months. Bottle propping was significantly more common, both at 1 week and 4 months, among women who had completely weaned their infants than among those who were still combining breast and formula feeding. Multivariate logistic regression indicated that 1-week risk factors for bottle propping were low socioeconomic status, being a multiparous single mother, and being a young mother (< or = 18 years old) with a female infant, while 4-month risk factors were complete weaning, delivery in a "nursery" (versus a "rooming-in") hospital, and lack of support by the mother's partner for breast-feeding. While the possible health risks associated with early bottle propping have not been well defined, the extent of the practice observed in this study suggests that such risks deserve further investigation.

Differences in morbidity between breast-fed and formula-fed infants.

To determine whether breast-feeding is protective against infection in relatively affluent populations, morbidity data were collected by weekly monitoring during the first 2 years of life from matched cohorts of infants who were either breast fed (BF) (N = 46) or formula fed (FF) (N = 41) until at least 12 months of age. Cohorts were matched for characteristics such as birth weight and parental socioeconomic status, and we controlled for use of day care in data analysis. Mean maternal educational level was high (16 years) in both groups. In the first year of life the incidence of diarrheal illness among BF infants was half that of FF infants; the percentage with any otitis media was 19% lower and with prolonged episodes (> 10 days) was 80% lower in BF compared with FF infants. There were no significant differences in rates of respiratory illness; nearly all cases were mild upper respiratory infections. Morbidity rates did not differ significantly between groups in the second year of life, but the mean duration of episodes of otitis media was longer in FF than BF infants (8.8 +/- 5.3 vs 5.9 +/- 3.5 days, respectively; p = 0.01). These results indicate that the reduction in morbidity associated with breast-feeding is of sufficient magnitude to be of public health significance.