Suboptimal breastfeeding practices are associated with infant illness in Vietnam

The importance of breastfeeding to infant growth and development [1], as well as long-term health outcomes [2], are now well recognized. Apart from being a natural source of nourishment, human milk contains glycans and secretory immunoglobulin, which offer protection against infectious disease [3, 4]. During the first six months of life, when digestive systems are not yet mature, exclusive breastfeeding (EBF) offers additional protection from illness by limiting exposure to contaminated foods and liquids. Substantial evidence shows that EBF for six months is associated with decreased morbidity and mortality from gastrointestinal infections, namely diarrhea, compared to other breastfeeding practices [5–7]. Infants who are exclusively breastfed for only three to four months are more likely than those exclusively breastfed for six months to suffer from conditions such as respiratory and urinary tract infections [8–12], otitis media [8, 13, 14], and necrotizing enterocolitis [8, 15]. The protective effects of breastfeeding are more pronounced in settings with poor sanitation and hygiene, where contamination of foods and liquids is more likely [16–18].

Based on such evidence, the World Health Organization (WHO) currently recommends that infants be breastfed within one hour of birth, exclusively breastfed for the first six months, and then continue to be breastfed until they are two years or older along with appropriate complementary feeding initiated at the age of six months [19]. However, adoption of these recommendations remains low in developing countries where only 39% of infants are exclusively breastfed [20]. Vietnam is an example of a country where poor practice of EBF prevails [21].

Although breastfeeding is practiced by 98% of mothers in Vietnam [22], adherence to global recommendations on infant and young child feeding (IYCF) practices is poor. Evidence shows that EBF rates among infants aged less than six months are in the range of 8 to 17% [21, 22], with rapid declines in rates over time [23–25]. Premature introduction of solids and semi-solids during the first three months of life has also been documented [24, 26], while continued breastfeeding to 24 months of age remains low at 22% [27]. To our knowledge no studies to date, including the National Nutrition Survey and the Multiple Indicator-Cluster Survey, have explored the impact of such feeding practices on child illness in Vietnam. Country-specific data on the relationships between breastfeeding practices and infant infection are essential to advocate for policies supportive of early and EBF. The objective of this paper is to investigate the association of infant feeding practices with the prevalence of diarrhea and acute respiratory infection (ARI) among infants aged 0–5 months in Vietnam.

In line with previously reported evidence, we found that breastfeeding practices in Vietnam are still sub-optimal. While all infants were ever-breastfed, a mere 20.2% were exclusively breastfed with a decreasing trend in age-specific EBF over the six-month period. This confirms that in Vietnam, the percentage of infants exclusively breastfed for the first six months continues to be among the lowest of 14 countries in the Asia Pacific region, where only two other countries report percentages below 21% [22]. We also found that only half of all infants were breastfed within the first hour, similar to the range of 35 – 49% of infants reported in a recent study on breastfeeding practices in urban and rural areas in Vietnam [25].

An overwhelming majority of infants, 73.3%, were given prelacteal foods. Liquids, solids, and semi-solids were introduced as early as immediately after birth. This is of concern as evidence shows that premature initiation of semi-solid and solid foods is associated with increased risk of nutritional imbalances and infectious disease, which in turn impact on the physical growth of the infant [24, 36]. In the study on the association of complementary feeding with infant growth in Vietnam, Hop and colleagues found that infants who were partially breastfed or weaned during the first three months of life had lower weight and height gain compared to those who were exclusively breastfed [24]. Reasons cited for early introduction of complementary foods by Vietnamese mothers include concerns on the lack of sufficient breast milk production, the need to return to employment, and a lack of family support to care for the child [24, 26]. This highlights the need for strengthened programs to raise awareness on early and exclusive breastfeeding, as well as for more supportive policies and workplaces for mothers.

An important finding of this study is that breastfeeding helps prevent diarrhea in infancy. Vietnam has seen rapid increases in coverage of improved drinking water and sanitation between 1990 and 2010, from 57% to 95% and 37% to 76% respectively [37]. Evidence indicates that the protective effects of breastfeeding are stronger in settings without access to hygienic water and sanitation facilities, as a result of decreased likelihood of contaminated foods and liquids [16–18]. In our study, even after controlling for several confounding factors related to the child, mother and household, the odds of diarrhea were still significantly lower among infants who were breastfed in the first hour after birth compared to those who were not. In addition, these odds were higher among infants who were predominantly or partially breastfed compared to those who were exclusively breastfed. These results suggest that the association between breastfeeding and reduced risk of diarrhea persists even in contexts with improved water and sanitation facilities.

Unlike other studies, however, we did not find that predominant breastfeeding was as protective against diarrhea as EBF – a phenomenon that has been reported in settings with hygienic water and sanitation facilities [38, 39]. Rather, we found that the adjusted odds ratios for diarrhea were roughly equal for predominantly and partially breastfed infants. This suggests that during the first few months of life, providing water and water-based liquids to infants is just as detrimental as the introduction of solids and semi-solids for risk of diarrheal illness.

For ARI, we also found lower prevalence of illness among infants who were exclusively breastfed compared to those who were predominantly or partially breastfed. This difference, however, was only significant for partial breastfeeding (adjusted OR 1.24, 95% CI 1.03 – 1.48). Previous studies have documented lower prevalence of and mortality due to ARI among infants who are exclusively breastfed compared to those who are not [5, 40, 41]. In two Bangladeshi studies which used the same breastfeeding classifications as in this study, increased prevalence of and mortality due to ARI was also associated with partial breastfeeding only [39, 42]. As was the case for diarrhea, prelacteal feeding was also associated with higher prevalence of ARI (adjusted OR 1.16, 95% CI 1.01 – 1.33), warranting the need for interventions tackling prelacteal feeding to protect infant from illness.

The stronger protective effect of optimal breastfeeding for diarrhea than for ARI may be explained by the differences in pathophysiology – gastrointestinal (GI) tract pathogens for diarrhea versus airborne pathogens for ARI. There are three pathways through which EBF can potentially protect against diarrhea: 1) limit introduction of diarrhea-causing pathogens to the GI tract; 2) immunoglobulin A in breast milk strengthens the immune system; and 3) breast milk contains glycans which function as soluble receptors that inhibit pathogens from adhering to their target receptors on the mucosal surface of the host gastrointestinal tract [3, 4]. Whereas for ARI, EBF can only be protective through the boost it provides to an infant’s immune system, however, it does not reduce exposure to the types of pathogens that cause ARI.

A limitation was the study’s cross-sectional design as identification of causal relationships between breastfeeding and child illness was not possible. In addition, data on severity and duration of diarrhea and ARI were not collected. These data would have provided insights on the pathways by which protection is conferred. Use of maternal recall to measure outcomes of interest may have biased our estimates of odds ratios, but the recall period was kept to two weeks in order to limit the potential of such bias. Despite these limitations, this analysis provides important country-specific evidence for policy makers to protect, promote, and support breastfeeding. To our knowledge, this is the first analysis to examine the relationship between breastfeeding practices and child illness in Vietnam. It is based on a large sample of infants representative of several provinces in Vietnam.

In conclusion, early initiation and exclusive breastfeeding protect against diarrhea and ARI. Results confirm that interventions to increase timely and exclusive breastfeeding would contribute to improving child health and nutrition in Vietnam.