LETTERS

Exclusive and predominant breastfeeding — a letter of reply

Betty Kirkwood^I,1; Rajiv Bahl^II; Jose Martines^III

^IDepartment of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, England (email: betty.kirkwood@lshtm.ac.uk)
^IIDepartment of Child and Adolescent Health and Development, World Health Organization, Geneva, Switzerland
^IIINewborn and Infant Health, Department of Child and Adolescent Health and Development, World Health Organization, Geneva, Switzerland

Editor – We are pleased by the interest generated by our paper (1). Important issues have been raised in the above comments by Ross & Piwoz, Kent, and Dadhich.

We agree with Kent and Dadhich that the findings of our study can only be generalized to resource-poor settings. We also agree with Ross & Piwoz that the results cannot be generalized to infants less than six weeks of age. Indeed we point out in the paper that our results are likely to be an underestimate of the overall protective effect of exclusive or predominant breastfeeding, since we only studied infants aged six weeks to six months, and since the analysis by the WHO Collaborative Study Team reported a higher protective effect for any breastfeeding during the first 2 months of life when compared with the effect among older infants (2).

The issue of the comparison of exclusive and predominant breastfeeding needs further clarification. As stated in our paper, the survival advantages of exclusive over predominant breastfeeding have not been well-studied. Even the studies of diarrhoeal morbidity referred to by Ross & Piwoz do not all include a comparison of exclusive and predominant breastfeeding (3–6).

Exclusive and predominant breastfeeding were both associated with substantially lower risk of mortality than partial or no breastfeeding in our study. Partially breastfed infants were 2.46 times (95% CI = 1.44–4.18) and non-breastfed infants 10.5 times (95% CI = 5.0–22.0) more likely to die than predominantly breastfed infants (our largest group). When exclusive breastfeeding was compared with predominant breastfeeding, the point estimate for the risk of mortality was 1.46 in favour of predominant breastfeeding but the confidence interval was wide (0.75–2.86) because of the relatively small number of exclusively breastfed infants. We therefore concluded that, in terms of survival, the benefits of shifting infants six weeks to six months of age from predominant to exclusive breastfeeding were likely to be smaller than those that could be achieved by shifting the non-breastfed or partially breastfed infants to exclusive or predominant breastfeeding.

The programmatic implications of our findings merit consideration. Efforts to promote exclusive breastfeeding need to be accelerated for several reasons. First, we see this as the only way to achieve high rates of predominant or exclusive breastfeeding. Second, the benefits of exclusive breastfeeding may go beyond survival, including long-term effects on non-communicable disease morbidity. We do not therefore feel that the findings of our study suggest a need for change in current policy. However, although promoting exclusive breastfeeding, we feel that substantial benefits in infant survival can be expected even if only high rates of predominant breastfeeding are achieved. In addition, we recommend that when promoting exclusive breastfeeding for the general population of infants, much greater attention be paid to reducing the prevalence of infants who are not breastfed or are partially breastfed than focussing on excluding the occasional use of water or infusions that are associated with predominant breastfeeding.

Competing interests: none declared.

References

1. Bahl R, Frost C, Kirkwood BR, Edmond K, Martines J, Bhandari N, et al. Infant feeding patterns and risks of death and hospitalization in the first half of infancy: multicentre cohort study. Bull World Health Organ 2005;83:418-26.

2. WHO Collaborative Study Team on the Role of Breastfeeding on the Prevention of Infant Mortality. Effect of breastfeeding on infant and child mortality due to infectious diseases in less developed countries: a pooled analysis. Lancet 2000;355:451-5.

3. Brown KH, Black RE, de Romana GL, Creed de Kanashiro HC. Infant-feeding practices and their relationship with diarrheal and other diseases in Huascar (Lima), Peru. Pediatrics 1989; 83:31-40.

4. Morrow AL, Reves RR, West MS, Guerrero ML, Ruiz-Palacios GM, Pickering LK. Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants. J Pediatr 1992;121:363-70.

5. Perera BJC, Ganesan S, Jayarasa J, Ranaweera S. The impact of breastfeeding practices on respiratory and diarrhoeal disease in infancy: A study from Sri Lanka. J Trop Pediatr 1999; 45:115-8.

6. Popkin BM, Adair L, Akin JS, Black R, Briscoe J, Flieger W. Breast-feeding and diarrheal morbidity. Pediatrics 1990;86:874-82.

1 Correspondence should be addressed to this author.