Sears MR, Greene JM, Willan AR, et al. Lancet. 2002;360:901–907
Purpose of the Study.
To assess the relationship between breastfeeding and the long-term outcomes of atopy and asthma.
One thousand thirty-seven children from a cohort of 1661 born in Dunedin, New Zealand, between April 1972 and March 1973 and residing in the Otago province of New Zealand at 3 years of age.
Breastfeeding history was obtained independently via interviews when the children were 3 years old. Participants were assessed within 1 month of their birthday at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, and 26 years. In addition to interviews and respiratory questionnaires, every 2 to 5 years from ages 9 to 26 years, participants had pulmonary function, bronchial challenge, and allergy skin tests performed.
Five hundred four (49%) children were breastfed for 4 weeks or longer and 533 (51%) children were not breastfed. More children who were breastfed were atopic to cats, house dust mites, and grass pollen from ages 13 to 21 years than those who were not breastfed. More children who were breastfed reported current asthma at assessments from 9 to 26 years than those who were not breastfed. The effects of breastfeeding were not affected by parental history of allergic rhinitis or asthma, socioeconomic status, parental smoking, birth order, or the use of sheepskin bedding during infancy.
Breastfeeding is not protective against atopy and asthma in the long-term.
Previous studies have yielded conflicting results regarding the effects of breastfeeding on the development of atopy and asthma. Although many studies have shown effects in the first 2 to 3 years of life, fewer have demonstrated any long-term benefit. This suggests that these effects, if any, are transient and serve more to delay than to truly prevent the development of allergy or asthma.