The study looked at the impact of the duration of breastfeeding and the introduction of alternative liquids or solids in addition to breast milk.
The researchers, from the Generation R Study, Erasmus Medical Center in The Netherlands, used questionnaires to gather data from over 5.000 children. They ascertained in the first twelve months after birth whether the children had ever been breastfed, when breastfeeding was stopped, and whether any other milk or solids were introduced.
Further questionnaires were completed when the children were aged one, two, three and four years to check whether they had any asthma-related symptoms.
The results showed that children who had never been breastfed had an increased risk of wheezing, shortness of breath, dry cough and persistent phlegm during their first 4 years, compared to children who were breastfed for more than six months.
The strongest links were seen with wheezing and persistent phlegm, as children were 1.4 and 1.5 times more likely to develop these symptoms if they had never been breastfed.
Children who were fed other milk or solids during their first four months in addition to breast milk had an increased risk of wheezing, shortness of breath, dry cough and persistent phlegm during the first four years, compared to children who were exclusively breastfed for their first four months.
While previous studies have shown a similar effect between breastfeeding and asthma risk, this research is the first that showed a link between the length of breastfeeding and the number of wheezing episodes. Also, this study found evidence that the first asthma-related symptoms occur earlier in life if children were breastfed for shorter lengths of time or not exclusively.
Doctor Agnes Sonnenschein-van der Voort, researcher at Generation R and lead author from the Erasmus Medical Center in The Netherlands, said: "The link of duration and exclusiveness of breastfeeding with asthma-related symptoms during the first four years was independent of infectious and atopic diseases. These results support current health policy strategies that promote exclusive breastfeeding for six months in industrialised countries."
MEDICA.de; Source: European Lung Foundation