Abstract
Associations between infant-feeding patterns and risk of IDDM were investigated in a nationwide Finnish case-control study of 690 IDDM children < 15 yr of age. Each child was matched by date of birth and sex to a randomly selected population-based control child. Univariate analysis revealed that the risk of IDDM was increased by approximately 1.5 in children for whom breast-feeding was terminated at < 2 mo of age, doubled in those who were exclusively breast-fed for < 2 mo, and doubled in those who were introduced to dairy products at < 2 mo of age. In further multivariate analyses of these factors, it was found that introduction of dairy products at an early age was the most important risk factor, and the observed univariate effects of duration of breast-feeding variables were explained by their correlation with this factor. This is the first observational study to show that early introduction of dairy products is independently associated with an increased risk of IDDM. Adjustment for mother's education and age, child's birth order, or birth weight did not affect the results.