Recurrence of sudden infant death syndrome (SIDS) is rare and has been overestimated by studies which have tried to quantify it, says a review published online ahead of print in Archives of Disease in Childhood.

The authors reviewed eight population-based studies published in English since 1970, which had reported relative risks of recurrence of SIDS ranging from 1.7 to 10.1 compared with the general population or controls.

The review checked that all relevant cases of SIDS had been identified reliably and that the cases had been compared with controls matched for risks of SIDS. It also checked that all the appropriate investigations had been conducted to ensure the diagnosis SIDS was accurate, including an autopsy, tests for familial causes of unexplained death and ruling out possible homicide.

All eight studies failed to meet these three criteria, which would have resulted in the risk of recurrence being overestimated, the authors said.

‘We conclude that, although an increase in risk is probable on theoretical grounds, the risk cannot be quantified from the available evidence,’ they said.

‘Families whose initial death was fully investigated and who have no major risk factors can be advised that, although the risk of a second death might be slightly increased, it remains very small.’

Source: British Medical Journal