• Cough/mechanisms/pharmacology

Breast feeding has been associated with many beneficial outcomes in children. Among other benefits, it has been linked to lower infant mortality,1 lower risk of sudden infant death syndrome,2 lower incidence of certain types of cancer3 and even higher intelligence.4 In terms of atopy and respiratory diseases, it has been associated with decreased risk of lower respiratory infections (LRIs)5 and childhood asthma (particularly over the first few years of life).6 7 On the other hand, a recent meta-analysis found no strong evidence that breast feeding helps prevent food allergies, eczema or allergic rhinitis.8 However, many studies looking at respiratory outcomes recorded breast feeding retrospectively or failed to thoroughly control for potentially important confounders.9

Whether these benefits extend into adulthood is still an open question. For example, a history of breast feeding may not affect the risk of high total cholesterol, high blood pressure or cardiovascular mortality.10 Unfortunately, studies evaluating the association between breast feeding and asthma in adults are scarce and have provided somewhat concerning results. In the Dunedin cohort, Sears et al reported an ~83% increased risk of asthma at 9–26 years of age among participants who were breast fed in infancy compared with those who were not breast fed.11 Likewise, the Tasmanian Asthma Study reported that exclusively breastfed children (of mothers with a history of atopy) had 46%–83% higher risk of asthma at 14, 32 and 44 years of age, with similar results for allergic rhinitis.12 However, these cohorts were recruited at 3 and 7 years of age, …