Children aged 6 years were more likely to be asthma sufferers if they had not been exclusively breastfed for at least 4 months, regardless of their mother's asthma status (odds ratio, 1.35; 95% CI 1.00-1.82).
Oddy WH et al (2002). Maternal asthma, infant feeding, and the risk of asthma in childhood. J Allergy Clin Immunol 110: 65-7 [Abstract]
