Association of Exposure to Cow's Milk Protein and β-Cell Autoimmunity

To the Editor.  —Recent discussions about the possible association between early infant diets and IDDM, including the Editorial by Drs Schatz and Maclaren,¹ have focused on the possible role of cow's milk. The possibility that the protective nature of breast-feeding may be the explanation for reported differences in incidence of diabetes between breast-fed infants and those artificially fed has received little attention. Although Norris et al² did not find such an association among children who have a familial risk of diabetes, this does not exclude a small protective effect of breast-feeding in the population of children without familial risk. As the authors acknowledge, it is likely that several factors play a role in the etiology of IDDM.One plausible explanation for the reported protection against IDDM is that breast-feeding has been found to protect infants from infection with enteroviruses such as coxsackievirus B.³ This protection results from direct neutralization of