Breastfeeding promotion does not decrease asthma or allergies

Journal of Family Practice, Jan, 2008

* Clinical question

Does an intervention to promote breastfeeding decrease the risk of asthma and allergy by 6 years of age?

* Bottom line

No. While a breastfeeding promotion initiative by the World Health Organization and UNICEF did increase the rates of breastfeeding at 3, 6, and 12 months (among mothers who had already decided to breastfeed their infants), it did not result in a lower rate of allergy and asthma symptoms among the children by age 6.

This study does not tell us whether continuous, exclusive breastfeeding decreases the risk of atopy, only that this particular intervention to increase breastfeeding rates did not.

Level of evidence

1b: Individual randomized controlled trials (with narrow confidence interval)

Study design

Randomized controlled trial (nonblinded)

Funding

Government

Allocation

Unconcealed

Setting

Outpatient (specialty)

Synopsis

As part of the Promotion of Breastfeeding Intervention Trial (PROBIT), these Canadian investigators enrolled (from 31 healthcare centers) 17,046 healthy Belarussian infants whose mothers had decided to breastfeed. Mothers and infants were randomly assigned to receive either usual care or an intervention from the WHO/UNICEF which was designed to encourage prolonged and exclusive breastfeeding. Randomization was by study site and thus allocation could not be concealed from investigators.

The intervention resulted in significantly more children being breastfed: 72.7% were still breastfeeding at 3 months (compared with 60% in the usual care group) and 19.7% were still being breastfed at 1 year (compared with 11.4% in the usual care group).

No differences seen in asthma rates. The development of asthma in the children was evaluated at 6 years of age, using the International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire, which was administered by a non-masked pediatrician at each study site. Children were evaluated in the group to which they were initially assigned (with intention-to-treat analysis).

The researchers found no difference in the development of asthma between the 2 groups of children, with approximately 11% of children reporting at least 1 episode of wheezing in the intervention group, compared with 9.6% in the control group. Similarly, hay fever and eczema rates were similar between the groups.

Study limitations. This study did not evaluate the likelihood of these allergic outcomes in children who received prolonged breastfeeding as compared with those who didn't. As a result, researchers could only conclude that this intervention to increase breastfeeding did increase breastfeeding rates, but it did not reduce the likelihood of allergic outcomes.

Kramer MS, Matush L, Vanilovich I, et al for the Promotion of Breastfeeding Intervention Trial (PROBIT) Study Group. Effect of prolonged and exclusive breast feeding on risk of allergy and asthma: cluster randomised trial. BMJ 2007; 335:815-823.