Randomised controlled trial of brief neonatal exposure to cows' milk on the development of atopy

OBJECTIVE: To determine the effect of brief early exposure to cows' milk on atopy in the first 2 years of life. DESIGN: Double blind, placebo controlled, randomised feeding intervention trial (Bokaal study). SETTING: Dutch midwifery practices. PARTICIPANTS: 1533 breast fed neonates. INTERVENTION: Exposure to cows' milk protein (n = 758) or a protein free placebo (n = 775) during the first 3 days of life. MAIN OUTCOME MEASURES: Clinical atopic disease and any positive radioallergosorbent (RAST) tests at 1 year of age. RESULTS: Atopic disease in the first year was found in 10.0% (cows' milk) v 9.3% (placebo) of the children, with a relative risk of 1.07; in the second year, atopic disease was found in 9.6% v 10.2%, respectively, with a relative risk of 0.94. Per protocol analysis showed similar results. Any RAST positive test was found in 9.4% (cows' milk) v 7.9% (placebo) of children, with a relative risk of 1.19. Stratified analysis for high family risk of allergy showed a doubled incidence of atopic disease but no effect from the intervention. CONCLUSION: Early and brief exposure to cows' milk in breast fed children does not increase the risk of atopic disease in the first 2 years