Breastfeeding and protection against respiratory tract infections in the first months of life

Background: the protective role against respiratory infections is included among the advantages of breastfeeding (BF).

Objective: to describe the pattern of BF in a cohort of newborns and its protective role against respiratory infections (RI) in the infant.

Material and methods: a cohort of 316 newborns (NB) from Madrid Health Districts 8 and 9 was followed by telephone calls every fortnight during the winter season recording clinical and epidemiological data. Nasopharyngeal aspirate was obtained in every patient with symptoms compatible with RI.

Results: one thousand, eight hundred and sixty-five phone calls [median: 4.2 (1-11)], and 106 scheduled visits were conducted. At the age of 1 month 56.1% of the infants were exclusively breastfed, at 3 months 39.4% and at 5 months 31.9%. The duration of BF was 65.1 days (SD: 43.49) and no factors were associated to a longer duration. Eighty nine acute RI were registered. The presence of siblings in school age increased the risk of RI by 1.74 (CI 95%:1.12-2.72) in all the strata of duration of exclusive BF. The risk of RI increased by 5 (CI 95%: 2.07-12.19) if breastfeeding lasted less than 1 month, by 9,8 (CI 95%: 4,06-23,66) between 30-60 days and by 3,4 (CI 95%: 1.28-9,19) if it lasted 60-90 days.

Conclusions: though many NB begin BF, only a third part of them go on with it at the age of 5 months. No covariant was associated with a longer duration. BF is a protector factor against RI when it lasts more than 90 days. So it must be promoted specially in those infants with siblings in school age.