Relationship of feeding modality to clinical features in Japanese infants with idiopathic neonatal hepatitis of the non-familial form

To clarify the relationship between idiopathic neonatal hepatitis and feeding type, that is, formula-milk feeding and breast-milk feeding, the medical records of 100 patients (68 male and 32 female babies) with idiopathic neonatal hepatitis of non-familial form referred to the medical centers of Akita University and Tohoku University during the past 18 years were reviewed. The patients were divided into two 9 year periods (1975–83 and 1984–92), and their clinical features were analyzed in terms of feeding type and sex. The number of patients enrolled decreased from 69 in the first half to 31 in the second half. The number of male patients dropped from 53 to 15, although the number of female patients (n = 16) remained the same in both 9 year periods. The frequency of formula-milk feeding significantly decreased in the second half (42/69 to 6/31, P < 0.01). Compared with the expected numbers of patients in the second half, calculated on the changes in the live birth population and feeding modality between the two halves, the actually enrolled numbers of patients in the second half were less in both the male and the formula-milk fed groups (× 0.35 and × 0.22), whereas the numbers of female and breast-milk feeding groups were close to the expected values (× 1.26 and × 1.08). When sex and feeding modality were combined, the formula-milk fed male group showed the lowest value (× 0.10), and the breast-milk fed female group showed the highest value (× 2.85). In conclusion, feeding type, especially in combination with gender, might be one causative factor in the occurrence of idiopathic neonatal hepatitis.