To that effect, a few groups have advocated the semi upright position of the infant during any type of feeding in order to decrease the incidence of ear infections 7,8. There are many reasons why conflicting results may be found in studies such as these. Obviously, randomized clinical trials are impossible and the observational approach used is subject to bias and errors due to confounding variables. A number of confounding variables were considered in the New Brunswick study The influence of family size was eliminated by choosing first time mothers. The ethnicity of the group was also relatively homogeneous.
Recall bias is probably the study's most significant bias.
The role of breast milk for the prevention of infections in non-developing countries may never be resolved to everyone's satisfaction. However, despite potential problems associated with data collection, the New Brunswick study shows a firm trend in confirming the benefits of feeding infants during the first six months of life . This should help reinforce health care professionals advice to mothers that breast is best. A global epidemiologic review. Ford K, Labbok M. Breast-feeding and child health in the United States.