NEW YORK, Sep 24 (Reuters Health) -- Introducing milk other than breast milk to infants younger than 4 months old increases the risk of asthma and atopy (a predisposition to certain allergies), according to a report.
"Public health interventions promoting an increased duration of exclusive breastfeeding may help to reduce... childhood asthma," Dr. Wendy Oddy and colleagues from the Institute for Child Health Research in West Perth, Australia, write in the September 25th issue of the British Medical Journal.
In the first study of its kind, the investigators followed 2,187 children from before birth through their 6th birthday, questioning their parents regarding various manifestations of asthma and allergy.
Children who were fed milk other than breast milk before 4 months of age experienced higher rates of all indicators of asthma and allergy, the report indicates. Such children were 25% more likely to be diagnosed with allergy and 30% more likely to have a positive skin test for allergies than were children who received only breast milk during their early months.
The total duration of exclusive breastfeeding was less important, though longer breastfeeding was associated with less asthma and allergy, the authors note.
Because the introduction of non-breast milk was more closely associated with asthma and atopy than the duration of breastfeeding, the investigators postulate that the exclusion of potentially allergy-causing components in milk other than breast milk may account for the protective effect.
The researchers also found increased risks of asthma and atopy among boys, infants born prematurely, and children living in households where smoking took place. Children who attended daycare before the age of 3 months were half as likely to develop asthma as others.
"Delaying the introduction of milk other than breast milk until at least 4 months of age may protect against asthma and atopy later in childhood," the investigators conclude.
