Full breastfeeding protection against common enteric bacteria and viruses: results from the MAL-ED cohort study

Abstract

Background: Breastfeeding is known to reduce the risk of enteropathogen infections, but protection from specific enteropathogens is not well characterized.

Objective: The aim was to estimate the association between full breastfeeding (days fed breast milk exclusively or with nonnutritive liquids) and enteropathogen detection.

Methods: A total of 2145 newborns were enrolled at 8 sites, of whom 1712 had breastfeeding and key enteropathogen data through 6 mo. We focused on 11 enteropathogens: adenovirus 40/41, norovirus, sapovirus, astrovirus, and rotavirus, enterotoxigenic Escherichia coli (ETEC), Campylobacter spp., and typical enteropathogenic E. coli as well as entero-aggregative E. coli, Shigella and Cryptosporidium. Logistic regression was used to estimate the risk of enteropathogen detection in stools and survival analysis was used to estimate the timing of first detection of an enteropathogen.

Results: Infants with 10% more days of full breastfeeding within the preceding 30 d of a stool sample were less likely to have the 3 E. coli and Campylobacter spp. detected in their stool (mean odds: 0.92-0.99) but equally likely (0.99-1.02) to have the viral pathogens detected in their stool. A 10% longer period of full breastfeeding from birth was associated with later first detection of the 3 E. coli, Campylobacter, adenovirus, astrovirus, and rotavirus (mean HRs of 0.52-0.75). The hazards declined and point estimates were not statistically significant at 3 mo.

Conclusions: In this large multicenter cohort study, full breastfeeding was associated with lower likelihood of detecting 4 important enteric pathogens in the first 6 mo of life. These results also show that full breastfeeding is related to delays in the first detection of some bacterial and viral pathogens in the stool. As several of these pathogens are risk factors for poor growth during childhood, this work underscores the importance of exclusive or full breastfeeding during the first 6 mo of life to optimize early health.

Keywords: MAL-ED; breastfeeding; enteropathogens; enteropathy; infant feeding.

FIGURE 1

Proportion of visits recording full breastfeeding for infants in each of the first 6 mo of life by site (n = 1712 children). BGD, Dhaka, Bangladesh; BRF, Fortaleza, Brazil; INV, Vellore, India; NEB, Bhaktapur, Nepal; PEL, Loreto, Peru; PKN, Naushehro Feroze, Pakistan; SAV, Venda, South Africa; TZH, Haydom, Tanzania.

FIGURE 2

Kaplan-Meier plots of the time until selected enteropathogens were first detected at each of the 8 MAL-ED sites (n = 1712 children). BGD, Dhaka, Bangladesh; BRF, Fortaleza, Brazil; EAEC, entero-aggregative Escherichia coli; ETEC, enterotoxigenic Escherichia coli; INV, Vellore, India; NEB, Bhaktapur, Nepal; PEL, Loreto, Peru; PKN, Naushehro Feroze, Pakistan; SAV, Venda, South Africa; tEPEC, typical enteropathogenic Escherichia coli; TZH, Haydom, Tanzania.

FIGURE 3

ORs (mean and 95% credibility interval) of detecting enteropathogens in stools as a function of the proportion of visits reporting full BF in 30-d periods preceding stool collection. Showing viral (left) and bacterial (right) pathogens. Logistic regression models also controlled for site as a random effect. n = 1712 children, except for the rotavirus model that excludes the 3 sites with routine vaccination (BRF, PEL, SAV), n = 1118. The intercept and age coefficients are not shown. BF, breastfeeding; BF initiated, whether or not breastfeeding was initiated within the first hour after birth; BRF, Fortaleza, Brazil; EAEC, entero-aggregative Escherichia coli; ETEC, enterotoxigenic Escherichia coli; Full BF prop., the proportion of visits reporting full breastfeeding from enrollment to each stool sample is considered as both a main effect and time varying term (multiplied by the log[age]); Other pathogens, a count of pathogen detected in the stool (excluding the pathogen of the response variable); PEL, Loreto, Peru; SAV, Venda, South Africa; SES, socioeconomic status index (per 10% increase, an index including water, sanitation, education, and wealth); tEPEC, typical enteropathogenic Escherichia coli; WAZ, weight-for-age z score assessed at enrollment.

FIGURE 4

Marginal HRs for the first detection of enteropathogens as a function of the proportion of time from birth to stool sampling when the child received full breastfeeding. The survival models also adjusted for socioeconomic status (including water, sanitation, education, and wealth), weight-for-age assessed at enrollment, breastfeeding initiation, sex, and the count of coincident enteropathogens. Full breastfeeding was included as both a main effect and time-varying term (multiplied by the log[age]). Models also controlled for site using a frailty term. n = 1712 children except for the rotavirus model that excludes the 3 sites with routine vaccination (BRF, PEL, SAV), n = 1118. BF, breastfeeding; BRF, Fortaleza, Brazil; EAEC, entero-aggregative Escherichia coli; ETEC, enterotoxigenic Escherichia coli; PEL, Loreto, Peru; SAV, Venda, South Africa; tEPEC, typical enteropathogenic Escherichia coli.