Aims: To investigate whether soft cot mattresses are a risk factor for the sudden infant death syndrome (SIDS).
Methods: A follow up postal questionnaire was sent to the subjects who were interviewed 3.8 years (range 2.2 to 5.2 years) previously as part of the New Zealand Cot Death Study, a large nationwide case-control study.
Results: 105 European SIDS cases were compared with 828 European controls. Soft cot mattresses were associated with an increased risk of SIDS (adjusted OR = 2.36; 95% CI = 1.06, 5,25) compared with average or hard mattresses. The firmness of the mattress did not interact with the sleeping position of infant.
Conclusions: Soft cot mattresses should be avoided.