The protective effects of breastfeeding on early life respiratory infections are well documented but there have been conflicting reports on protection from asthma in late childhood.
Two recent studies have looked at lung function in children who were breastfed. A study in the Isle of Wight (1) (n=1,456) assessed breastfeeding practices and duration prospectively from birth and at subsequent follow-up visits (one and two years). Breastfeeding duration was categorized as not breastfed (n=196); <2 months (n=243); 2 to <4 months (n=142) and >=4 months (n=374). Lung function was measured at age 10 (n=1,033) using differing measures: forced vital capacity (FVC) and forced expiratory volume in one second (FEV1); FEV1/FVC ratio; and peak expiratory flow (PEF). Maternal history of asthma and allergy were noted at birth. The effect of breastfeeding on all these measures was analyzed adjusting for birthweight, sex, current height and weight, family social status and maternal education. The researchers found that compared to those who were not breastfed, statistically significant increases in FVC, FEV1 and PEF were noted in children who were breastfed for at least four months.
A second study in Arizona (2) recruited babies at birth (n=1246) and analysed data from the group on whom lung-function testing was performed at ages 11 and/or 16 years and who had provided data regarding infant-feeding practices (n=679). Early formula milk introduction resulted in reduced FVC and lower FEV1/FVC ratio. The researchers concluded that longer duration of breastfeeding favorably influences lung growth in children. However, they noted that in the presence of maternal asthma, longer breastfeeding is associated with decreased airflows. The clinical significance of this is unknown and further research is indicated.
1. Ogbuana IU, Karmaus W, Arshad SH et al (2008) The effect of breastfeeding duration on lung function at age 10 years: A prospective birth cohort study. Thorax: 10.1136/thx.2008.101543
2. Mahr T (2008) Effect of breastfeeding on lung function in childhood and modulation by maternal asthma and atopy. Pediatrics: 122(Supplement_4); S176-S177
