Risk of sudden infant death syndrome among siblings of victims

The risk of sudden infant death syndrome (SIDS) is greater among siblings of children who died of SIDS, according to a recent study.

SIDS is defined as the death of an infant aged under 1 year after an extensive postmortem investigation. It is the leading cause of death in the first year of life, but its causes remain unclear. Hypothesized risk factors of SIDS include an exogenous stressor, a critical development period, and an underlying vulnerability.

As SIDS risk still cannot be predicted, determining the association between a family history of SIDS and subsequent SIDS is needed to identify children at risk of SIDS. A study was conducted to determine if SIDS risk increases in siblings of children who died of SIDS.

Health and administrative registries in Denmark were used to conduct the study. These registries contained registration data on parents and siblings of individuals born in Denmark, along with complete data on hospital diagnosis and cause of death. 

Information on those who had died from SIDS was collected from the Danish Cause of Death Register. If an infant aged under 1 year died to a cause unknown after thorough autopsy, their death was registered as SIDS.The Danish Medical Birth Registry was used to determine siblings of children who had died of SIDS. 

The study population included all births in Denmark between January 1, 1978, and December 31, 2016, aged under 1 year at the time of death. Stillborn babies and adopted children were excluded. Data was also collected on household income and mothers’ educational status.

Ninety percent of SIDS cases occurred within the first 6 months of life, with a median age of 3 months. Of children experiencing SIDS, 61% were male. 

While sex and mother’s age at birth did not lead to a significant difference in SIDS cases between the 2 study groups, sibling SIDS cases more often lived in low-income households and had mothers with only elementary school education.

Of 2,666,834 births, 1540 cases of SIDS were identified. The rate of SIDS was higher among siblings of children who died of SIDS compared to a general population. A 4-fold higher risk was found among this group, indicating that family history of SIDS should be considered when determining SIDS risk.

Reference

Glinge C, Rossetti S, Oestergaard LB, Stampe NK, Lynge TH, Skals R, et al. Risk of sudden infant death syndrome among siblings of children who died of sudden infant death syndrome in Denmark. JAMA Netw Open. 2023;6(1):e2252724. doi:10.1001/jamanetworkopen.2022.52724