Researchers at the Royal Hospital for Sick Children in Glasgow identified 131 infants who died of sudden infant death syndrome (cases) and 278 healthy infants of the same age (controls). They used a questionnaire to compare details of childcare practices from both case and control families.
They found that routine use of an infant mattress previously used by another child was significantly associated with an increased risk of sudden death syndrome, especially if the mattress was from another home. They also found that the associated risk was particularly high if the infant was sleeping on the used mattress at time of death.
After further analysis to account for any bias, the authors conclude that this association is relatively strong. In addition, toxigenic bacteria that have been implicated in sudden infant death syndrome do reside in used infant mattresses, they say. However, insufficient evidence is available to judge whether this is a cause and effect relation.