Associations of infant feeding patterns and milk consumption with cow's milk protein antibody titres were studied in 697 newly-diagnosed diabetic children, 415 sibling-control children and 86 birth-dateand sex-matched population-based control children in the nationwide "Childhood Diabetes in Finland" study. IgA and IgG antibody titres to the proteins of cow's milk formula, BLG and BSA, and IgM antibody titres to cow's milk formula proteins were measured by ELISA. Several inverse correlations were observed between the duration of breast-feeding or age at introduction of dairy products and antibody titres, and positive correlations were observed between milk consumption and antibody titres in all three populations studied. Multivariate analyses which included the infant feeding variables, milk consumption and current age simultaneously showed that the earlier the introduction of dairy products and the greater the consumption of milk was, the higher several antibody titres were. High IgA antibody titres to cow's milk formula were associated with a greater risk of IDDM both among diabeticpopulation-control and diabetic-sibling-control pairs when adjusted for other cow's milk antibody titres, dietary variables and in diabetic-sibling-control pairs also for ICA. The results suggest that young age at introduction of dairy products and high milk consumption during childhood increase the levels of cow's milk antibodies and that high IgA antibodies to cow's milk formula are independently associated with increased risk of IDDM. [Diabetologia (1994) 37: 381-387] Key words Infant feeding, dairy products, cow's milk protein antibodies, IDDM, childhood, islet cell antibodies, insulin autoantibodies.
Observations on the possible inverse association between duration of breast-feeding or proportion of breast-fed children and the risk of IDDM have been conflicting [1,2]. Several studies have suggested that an * See Acknowledgements