Cot deaths in Edinburgh: infant feeding and socioeconomic factors.

One hundred and twenty-six consecutive cases of sudden infant death syndrome (SIDS) in the Edinburgh area have been studied with particular reference to the interrelationship of feeding, associated biochemical changes, and social status. There was an excess of cases born to parents in Social Classes IV and V: the effect was maximal in children who dies beyond 12 weeks of age. A low-grade uraemia was discovered in approximately one-fifth of the cases; analysis showed this to be related most strongly to bottle-feeding. Feeding habits were found to be associated with social class and this accounted for the relationship between bottle-feeding and the youth of mothers and also for an apparent relationship between uraemia in the infant and social class of the mother. Mothers of SIDS children were younger than expected and SIDS was found to be electrolyte imbalance is common in SIDS cases, nor did the findings support the suggestion that cross-infection due to overcrowding is an important aetiological factor. The significant factors of young motherhood, low social status, bottle-feeding, and mild uraemia in the babies are interrelated and seem to focus attention on unwitting 'mothering problems'. It is, however, not easy to see how this, or any other hypothesis, can account for all cases of SIDS.