Volume 360, Number 9337 21 September 2002
Long-term relation between breastfeeding and
development of atopy and asthma in children and
young adults: a longitudinal study
Malcolm R Sears, Justina M Greene, Andrew R Willan, D Robin Taylor, Erin M
Flannery, Jan O Cowan, G Peter Herbison, Richie Poulton
Correspondence to: Prof Malcolm R Sears, Firestone Institute for Respiratory
Health,
St Joseph's Healthcare and McMaster University, 50 Charlton Avenue, Hamilton,
Ontario L8N 4A6, Canada (e-mail:[log in to unmask])
Summary
Background Breastfeeding is widely advocated to reduce risk of atopy and
asthma,
but the evidence for such an effect is conflicting. We aimed to assess
long-term
outcomes of asthma and atopy related to breastfeeding in a New Zealand birth
cohort.
Methods Our cohort consisted of 1037 of 1139 children born in Dunedin, New
Zealand,
between April, 1972, and March, 1973, and residing in Otago province at age 3
years.
Children were assessed every 2-5 years from ages 9 to 26 years with respiratory
questionnaires, pulmonary function, bronchial challenge, and allergy skin
tests.
History of breastfeeding had been independently recorded in early childhood.
Findings 504 (49%) of 1037 eligible children were breastfed (4 weeks or longer)
and
533 (51%) were not. More children who were breastfed were atopic at all ages
from 13
to 21 years to cats (p=0
·0001), house dust mites (p=0·0010), and grass pollen
(p<0·0001) than those who were not. More children who were breastfed reported
current asthma at each assessment between age 9 (p=0·0008) and 26 years
(p=0·0008) than those who were not. Breastfeeding effects were not affected by
parental history of hayfever or asthma. Multifactor analysis controlling for
socioeconomic status, parental smoking, birth order, and use of sheepskin
bedding in
infancy, showed odds ratios of 1·94 (95% CI 1·42-2·65, p<0·0001) for any
allergen
positive at age 13 years, 2·40 (1·36-4·26, p=0·0003) for current asthma at 9
years, and
1·83 (1·35-2·47, p<0·0001) for current asthma at 9-26 years by
repeated-measures
analysis.
Interpretation Breastfeeding does not protect children against atopy and asthma
and
may even increase the risk.
Lancet 2002; 360: 901-07
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