Siblings of cot death victims have four-fold cot death risk

Siblings of cot death victims have a four-fold higher risk of cot death, according to research presented today at EHRA 2018, a European Society of Cardiology congress. The 38-year study in nearly 2.5 million infants suggests that autopsies should be carried out on SIDS victims and that family members should have cardiology tests.

The incidence of sudden infant death syndrome (SIDS), also known as cot death, has declined in the last 20 years following public health campaigns to avoid placing infants in the prone sleeping position and not to smoke during pregnancy or near infants.

However, "SIDS remains a leading cause of death during the first year of life, affecting thousands of infants each year in Europe and the US," noted study author Dr Charlotte Glinge, a physician and PhD student at The Heart Centre, University Hospital of Copenhagen, Denmark.

The exact cause of SIDS is unknown, but it is thought to be caused by a combination of genetic and environmental factors. The aim of this study was to determine whether siblings of SIDS victims have a higher risk of SIDS than the general population.

The study used nationwide health and administrative registries in Denmark, where all residents are given a permanent and unique civil registration number at birth or immigration that enables linkage of individual registry data. The study included nearly 2.5 million infants under one year of age between 1978 and 2015.

From the cause of death registry, the researchers identified 1,535 infants who were the first, or only, infant in a family to die of SIDS during the 38-year study period. From the Danish fertility registry, the researchers identified 2,373 younger brothers and sisters of the group of infants who died of SIDS. They were followed from the date of their elder sibling's death from SIDS to whichever of the following outcomes came first: SIDS, death from another cause, emigration, age of one year, or study end on 31 December 2015.

The researchers calculated the incidence of SIDS in the younger siblings compared to the general population. After adjusting for sex, age, and calendar year, they found that the younger siblings of SIDS victims had a four-fold increased risk of SIDS compared to the general population.

Dr Glinge said that a post-mortem examination by a cardiac pathologist should be undertaken in all young victims of sudden death. Although SIDS is believed to be a combination of genetic and environmental factors, if a genetic mutation is identified that may have contributed to SIDS, siblings and parents should be tested for the mutation.

All parents should be asked about family history of sudden cardiac death. Parents and siblings should be offered cardiology tests, including an electrocardiogram (ECG) and echocardiography, to provide the best chance of identifying an inherited cardiac condition. Management of surviving family members is complex and requires a multidisciplinary team.

Dr Glinge said: "All parents should follow public health advice on how to prevent SIDS. But by screening families of SIDS victims, we can identify whether there are additional steps that can be taken to stop a sibling dying of SIDS."