Adoption of safer infant feeding and postpartum sexual practices and their relationship to maternal HIV status and risk of acquiring HIV in Zimbabwe.

OBJECTIVE: To examine the relationships between maternal knowledge and concern about HIV status, adoption of preventive practices and risk of acquiring HIV in Zimbabwe. METHODS: Knowledge and behavioural data were collected via interview from 2595 mothers enrolled in ZVITAMBO, a randomized trial of postpartum vitamin A supplementation that also offered education on safer infant feeding and sexual practices. Mothers were tested for HIV at delivery; those uninfected at baseline were retested during study follow-up. Logistic regression methods were used to identify variables associated with adoption of preventive behaviours and, for HIV-negative mothers, their relationship to risk of acquiring HIV post-delivery. RESULTS: A total of 518 mothers (20%) reported practicing safer sex and 289 mothers (11%) reported modifying their feeding behaviour because of HIV. Fear of transmitting HIV (50.4%) and protecting the baby's health (30.9%) were the most frequently cited reasons for behaviour change. Forty-nine HIV-negative mothers acquired HIV during the first postpartum year. After taking into account other significant covariates, mothers who were concerned about their own HIV status were 1.9 times more likely (95% CI: 1.05-3.52; P = 0.03), and those reporting safer sex practices were 58% less likely to become infected (adjusted odds ratio: 0.42; 95% CI: 0.17-1.04; P = 0.06). Married women who reported practicing abstinence to prevent HIV were 3.2 times more likely to become infected than non-abstaining mothers (P = 0.01), while there were no new HIV infections among abstaining single mothers. CONCLUSIONS: Greater emphasis should be given to safer sex practices among women who test negative in mother-to-child HIV prevention programmes.

Feeding practices and growth among low-income Peruvian infants: a comparison of internationally-recommended definitions.

BACKGROUND: Data from a longitudinal study of 153 low-income Peruvian infants were used to assess the relationship between internationally-recommended definitions of feeding practices and infants' monthly weight gain and weight status at 12 months. METHODS: Infants were classified into feeding categories using monthly reported data. Analysis of variance was used to assess the relationship between reported usual feeding practices and growth. Reported breastfeeding practices were compared to observed breastfeeding practices and to weighted breast milk intakes to determine the validity of recommended breastfeeding definitions. RESULTS: Breastfed infants who consumed non-human milks during the first month of life gained less weight during that month (P < 0.002) than exclusively and predominantly breastfed infants. Reported daily nursing frequency was associated with observed nursing frequency and breast milk energy intake (P < 0.05) for infants < 9 months old. Patterns of growth varied according to early diets. Infants who consumed breast milk and non-human milks and those who were fully weaned by 4 months were more likely to be underweight at 12 months than other infants. Infants classified as token breastfeeders ( < or = 3 times/24 hours) from 0 to 120 days had monthly gains that were similar to those of fully weaned infants. CONCLUSIONS: Infants feeding definitions should 1) continue to differentiate exclusively breastfed infants from other infants who are almost exclusively or predominantly breastfed; 2) distinguish partially breastfed infants who consume only non-breastfeeding frequency or the % of their total daily energy that comes from breast milk.

Potential for misclassification of infants' usual feeding practices using 24-hour dietary assessment methods.

Feeding patterns of 131 low income Peruvian infants were assessed by 1574 single-day studies (12-h observations plus 12-h recall) of dietary intake and by mothers' monthly reports of usual feeding practices to determine whether feeding pattern classification depends on the assessment method used. Results suggest that single-day studies produce a different view of feeding practices than do mothers' reports of usual behavior. Exclusive breast-feeding in infants younger than 4 mo was observed 25% more often than reported. Non-human milk consumption was reported 30% more often than observed. Disagreement between reported and observed practices was related by logistic regression analyses to mother's age and education, number of children younger than 5 y in the home and infant age and illness on the observation day. Most disagreement between reported and observed behavior could have been due to daily variation in feeding practices. Consumption during the past 24 h should not be used alone as the basis for classifying infant feeding practices in survey research.

The relationship between infants' preceding appetite, illness, and growth performance and mothers' subsequent feeding practice decisions.

Data from a longitudinal study of 153 low-income Peruvian infants were used to examine (i) whether infant characteristics such as appetite, illness and past growth performance are related to subsequent changes in their feeding practices (e.g. addition of non-human milks, solid foods, weaning), and (ii) whether this relationship depends on maternal characteristics such as feeding exposure and experience (MFEE). With one exception, infants were breastfed from birth. Feeding practices during the first month of life were related to practices throughout infancy. Most mothers changed their practices once (61%) or twice (34%) from birth to 6 months. Low weight gains from 1 to 2 (P < 0.003) and 2 to 3 (P < 0.04) months were identified as significant predictors of feeding changes during the following months, using logistic regression models that also adjusted for MFEE, infant gender, previous practice, and previous practice change. The interaction between past weight gain and MFEE (objective ii) was not statistically significant in the logistic regression models. However, when analyzed separately, the relationships between low weight gains and subsequent feeding changes were observed for high but not low MFEE mothers. The prevalences of anorexia and infection (diarrhea, respiratory, and/or fever), and poor length gain during the previous month were not related to subsequent changes in feeding practices. These results suggest that poor growth influences feeding practices from 2 to 4 months, when exclusive breastfeeding is recommended.

Indicators for monitoring the growth of peruvian infants: weight and length gain vs attained weight and length.

OBJECTIVES: To determine appropriate indicators and age intervals for growth monitoring in this population, the relationship between monthly weight and length indicators and nutritional status at 12 months was evaluated among 102 low-income Peruvian infants. METHODS: Cutoffs for defining adequate vs slow growth were obtained from published reference data, and sensitivities and specificities of each indicator were calculated. RESULTS: Low weight gain in early infancy, especially from 1 to 2 months, is useful for predicting low weight at 1 year (sensitivity = 81%, specificity = 65%, 25th percentile cutoff). Use of actual weight at 2 months, however, produces comparable results (sensitivity = 86%, specificity = 57%, 50th percentile cutoff). Monthly length gains were weak predictors of low length for age. Neither weight nor length gains accurately predicted the opposite form of undernutrition. Nonhuman milk consumption before 4 months and poor appetite from 3 to 12 months were related to low early weight gain and subsequent undernutrition. CONCLUSIONS: Growth monitoring programs in this population should enroll infants at birth, monitor actual weight, promote exclusive breast-feeding and delayed introduction of nonhuman milk, and provide specific feeding advice to mothers of infants with frequently depressed appetite.

Within- and between-individual variation in energy intakes by low-income Peruvian infants.

OBJECTIVES: (i) To examine the components of variation in infant energy intake. (ii) To calculate the precision of estimates of energy intake from different sources. (iii) To estimate the number of dietary studies required to estimate true energy intake with varying degrees of precision. DESIGN: Energy intakes were determined from monthly 12-h observations with test-weighing of breastmilk and all foods consumed. Variance components were evaluated by pooling results of studies performed when infants were 1-4, 5-8 and 9-12 months old. SETTING: Pueblo Joven Huáscar, a low-income, peri-urban community in Lima, Peru. SUBJECTS: 124 infants who were enrolled at birth and followed monthly. RESULTS: Within-to-between infant variance ratios were > 1.0 for total energy and energy from solid foods, and < 1.0 for energy from breast- and non-human milks during the 4-month periods examined. Total energy and energy from breastmilk were estimated to within 13-24% of infants' true intake. Non-breastmilk energy was estimated to within 19-143% of true intake. Four dietary studies per age period are required to estimate total energy and breastmilk energy consumption with 20-30% precision. At least 16 studies are required to estimate infants' average energy intake from solid foods from 5-8 months with 30% precision. CONCLUSIONS: The degree of precision achieved during assessment of infants' usual energy intake changes with age and composition of the diet. Thus, the number of dietary studies required to obtain a fixed level of precision differs according to these characteristics.

PIP: Pueblo Joven Huascar, a low-income periurban community in Lima, Peru, was chosen 1) to examine the components of variation in infant energy intake, 2) to calculate the precision of estimates of energy intake from different sources, and 3) to estimate the number of dietary studies required to estimate true energy intake. The sample consisted of 1564 observations on 124 infants who were enrolled at birth and followed monthly. Total energy intake, and energy from breastmilk, nonhuman milk, or other liquids and solid food sources were calculated for each observation. Means, standard deviations and coefficients of variation for total energy and source-specific energy intakes were calculated for infancy (1-12 months), and for the successive 4-month periods. For months 1-12, the pooled ratio for total energy was 2.91. Pooled, age-specific coefficients of within-infant variation in total energy intake were 70% greater and between-infant coefficient of variation were 20-50% lower compared to a study of 48 breastfed British infants. For months 1-12, variance ratios for breastmilk and nonhuman milk were 0.75 and 1.15, compared to ratios of 3.72 and 3.69 for non-milk liquids and solid foods, respectively. For total energy, total energy per kg body weight, and breastmilk energy, the within-to-between infant variance ratios were larger during 1-4 months compared to later infancy. Ratios for energy from nonhuman milk, other liquids, and solid foods were somewhat greater from 9 to 12 months compared to 5-8 months. These data suggest that pooled monthly dietary studies will give estimates of infants' mean total and breastmilk energy intakes that are within 20-30% of their true mean intakes during each of the 4-month age periods examined. Monthly estimates of solid food energy intake by infants from 9-12 months will also be within 20% of the truth. At least 16 dietary studies are required, however, to estimate infants' average solid food energy intake when they are 5-8 month old, and be within 30% of their true intake for this period.

Potential for misclassification of infants' growth increments by using existing reference data.

The observed variances in monthly weight and length gains of 96 Peruvian infants were compared with predicted variances obtained by applying the reference curve-fitting methods to the same Peruvian data. Predicted variance estimates were significantly less (P less than 0.0001) than the observed variances from 2 to 12 mo of age. The extent of underestimation in total variance that occurred when 1-mo growth-increment reference data were generated by curve-fitting and interpolation was approximated. This underestimation, caused by not taking into account infants' random deviations from their own growth trajectories, ranged from 59% to 94% and resulted in misclassification of approximately 24-67% of infants as abnormal gainers (below the 5th percentile or above the 95th percentile with respect to existing reference data) in the intervals evaluated.