Suboptimal breastfeeding practices are associated with infant illness in Vietnam

This study used data from a baseline survey undertaken as part of an evaluation of Alive & Thrive (A&T), an initiative that aims to improve child nutrition by addressing suboptimal IYCF practices in Vietnam [28, 29]. The survey was conducted in 2011 in 340 communes of 11 provinces where the A&T program is implemented. A two-stage cluster sampling technique was used to obtain a representative sample of 10,834 pairs of mothers and children under the age of 24 months. For each province, this involved: 1) selecting communes using population proportional to size and 2) selecting mother–child pairs using systematic random sampling. Given the focus on early and exclusive breastfeeding practices, analysis in this study was restricted to a sample of 6,068 pairs of mothers and infants under the age of six months.

Ethical approval for the survey was provided by the Institutional Review Board (IRB) of the Institute of Social and Medicine Studies in Vietnam (IORG number: 000663, FWA number: 00016762). Written informed consent was obtained from all mothers participating in the study.

Data for this study were drawn from a baseline household survey within the context of the larger evaluation of A&T’s interventions in Vietnam. This cross-sectional survey conducted in July and August 2011 was carried out in 11 provinces of 15 provinces where A&T operates. Data were collected by face-to-face interviews using a structured questionnaire. The outcomes of interest in this study were diarrhea and ARI, which were collected through maternal recall of symptoms in the two weeks prior to the survey. Diarrhea was defined as 3 or more loose stools in a 24-hour period [30], and ARI was defined as the presence of cough/cold with fever [31].

The main predictor was breastfeeding practices, which were classified and defined as per WHO indicators [32]: 1) early initiation of breastfeeding (defined as the proportion of children born in the last 24 months who were put to the breast within one hour of birth); 2) prelacteal feeding (defined as the proportion of children born in the last 24 months who were given any food or liquid other than breast milk during the first three days after birth); and 3) exclusive breastfeeding (defined as the proportion of infants 0–5 months of age who were fed exclusively with breast milk in the previous 24 hours - no foods, no liquids with the exception of medications such as drops, syrups). Two optional breastfeeding indicators were also considered in the analysis: 1) predominant breastfeeding (when the infant is given water, water-based drinks, fruit juice, ritual fluids, in addition to breast milk); and 2) partial breastfeeding (when the infant is given liquids and non-liquids such as milk, non-milk based products and other foods in addition to breast milk, non-breastfed infants were also included in this group).

Covariate variables were considered at the child, maternal, and household levels. At the child level, we adjusted for child age and gender. At the maternal level, we controlled for mother’s age, occupation, and highest level of education (primary, secondary, high school, and college or higher). At the household level, we adjusted for the household’s location, socioeconomic status (SES), and hygiene condition. Household location – urban or rural – was identified based on current administrative classifications in Vietnam [33]. SES index was calculated by principal components analysis [34], using several factors, such as ownership of property and land, household assets, housing conditions, and access to utilities. The SES index was then categorized into quintiles with the lowest quintile representing the ‘poorest’ in the population and the highest quintile representing the ‘richest’. For hygiene, we used two variables: type of toilet and sources of drinking water.

Descriptive statistics were used to report the background characteristics and breastfeeding patterns of the study sample; percentage, mean and standard deviation (SD) are presented. Bivariate and multivariate logistic regressions were used to examine the associations between different breastfeeding practices and the prevalence of diarrhea and ARI. Practices for which associations were significant (p < 0.05) in bivariate analysis were included in the final model which controlled for confounding factors related to the child, mother, and household. All statistical analyses were carried out using the Stata 11.0 statistical package (Stata Inc., TX, USA) [35]. The cluster command in Stata was used to adjust for clustering effects at the commune level.

Table 1 outlines the baseline sociodemographic characteristics of the study sample. The mean age of children was 3.3 months (SD 1.6, range 0.03-5.98), and there were around the same number of boys (52%) and girls (48%). The mean age of mothers was 27.3 years (SD 5.5, range: 16.5 - 47.3), and nearly half of them (48.2%) achieved secondary school as the highest level of education. The majority of mother-child pairs (83.3%) resided in rural areas. Over 60% of study households had toilets with septic or semi-septic tanks, and nearly half relied on open well, rain or pool/lake water as their main source of drinking water.

All children surveyed were ever breastfed. While half breastfed within one hour of birth, the majority of infants (73.3%) were also given prelacteal foods in the first three days after birth – namely infant formula, plain water, or honey. On average, only 20.2% of children 0–5 months old were exclusively breastfed, as opposed to 32.4% who were predominantly breastfed and 47.4% who were partially breastfed.Figure 1 provides a breakdown of breastfeeding patterns by child’s age in months. In the first month of life, 41.4% of infants were exclusively breastfed, and a similar percentage, 38.9%, predominantly breastfed. Prevalence of EBF, subsequently, declined over each consecutive month, primarily displaced by feeding of plain water, breast milk substitutes, and solid to semi-solid foods, to 6.2% by the age of 5 – 5.9 months. Around 20% of infants were introduced to solid and semi-solid foods in the first month after birth, a practice which becomes more prevalent after the age of three months: 80.5% of infants were partially breastfed at 5 months as opposed to 31.8% at 2 – 2.9 months.

During the two weeks prior to the survey, 5.3% and 24.5% of all children had diarrhea and ARI respectively. The prevalence of ARI increased from 11% in the first 30 days to 33% in month five. Similarly, the prevalence of diarrhea increased from about 2% to 8% during the same period (Figure 2). Prevalence of illness varied depending on the type of breastfeeding practice (Figure 3). Table 2 presents the unadjusted and adjusted odds ratios for having diarrhea and ARI in the two previous weeks, by type of feeding practice. In bivariate analysis, early initiation and EBF were associated with lower odds of diarrhea, while the opposite was true for prelacteal feeding, predominant and partial breastfeeding. Similar results to bivariate analysis were confirmed in multivariate analysis after controlling for child, maternal, and household related factors. Adjusted odds ratios of diarrhea were 0.74 (95% CI 0.58, 0.93) for early initiation and 1.53 (95% CI 1.15, 2.03) for prelacteal feeding. Compared to exclusively breastfed infants, adjusted odds ratios of diarrhea were 1.52 (95% CI 1.05, 2.21) for predominantly and 1.55 (95% CI 1.07, 2.24) for partially breastfed children.

Breastfeeding practice was also significantly associated with ARI. Compared to exclusively breastfed infants, the odds ratio for ARI among those who were partially breastfed was 1.71 (95% CI 1.46, 2.02). This association remained significant after adjusting for confounders [AOR: 1.24 (95% CI 1.03, 1.48)]. In addition, infants with prelacteal feeding were more likely to experience ARI compared to non-prelacteal feeding counterparts (AOR 1.16, 95% CI 1.01, 1.33). While the protective effects of exclusive breastfeeding for diarrhea declined with child age, this effect for ARI appears to have remained constant (Figure 4).