, according to new data published online in Pediatrics.
SUID occur in infants less than 1 year old. The deaths happen without an obvious cause before investigation and account for 3,400 deaths per year in the United States.
Alexa B. Erck Lambert, MPH, Maternal and Infant Health Branch of the Centers for Disease Control and Prevention (CDC), led the study that examined 7,595 such deaths in 23 US jurisdictions from 2011 to 2020, using data from the CDC’s SUID Case Registry.
The researchers reported that the prevalence of surface sharing ranges from 34% to 64% among living infants and about 50% among SUID.
Common Factors
They found common factors when infants share sleep space compared with infants who did not. Those who shared space, for example, were often 0-3 months old; publicly insured; non-Hispanic Black; found in an adult bed, couch, or chair; exposed to maternal cigarette smoking prenatally; and supervised by a parent when they died or had a supervisor who was impaired by drugs or alcohol at the time of death.
Having a supervisor who was impaired by drugs or alcohol was much more common among sharing (16.3%) than nonsharing infants (4.7%).
The American Academy of Pediatrics (AAP) guidance says a safe sleep environment for infants includes a place to sleep on a nonshared sleep surface (in a crib or bassinet) without soft bedding, and lying on the back facing up.
Most Who Died had Multiple Unsafe Sleep Factors
At least 76% of all SUID had multiple unsafe sleep factors present, regardless of whether the infants shared sleep space. Unsafe sleep factors include an inclined or soft sleep surface, sleeping on the side or stomach, sleeping with soft or loose bedding or objects, not breastfeeding, prenatal or environmental exposure to cigarette smoke, and overheating.
Sharing sleep space combined with parents’ smoking and maternal alcohol or drug use greatly increases risk of sudden infant death, the authors noted.
Sharing More Common With Multiples
Among SUID, surface sharing was more common among multiples than singletons and more common in an adult bed than in the same crib. The authors noted that parents often cite financial reasons for such arrangements.
However, AAP recommends multiples sleep on separate surfaces. The authors say pediatricians and other healthcare providers should be aware of free crib distribution programs. A study by Hauck et al. found “crib distribution and safe sleep education positively influence knowledge and practices about safe sleep.”
Robin Haynes, PhD, who studies causes underlying the pathology of SIDS at Boston Children’s Hospital, pointed to the Cribs for Kids website as a place for parents and clinicians to start for help with providing separate sleeping surfaces.
Dr. Haynes said the large number of infants included is a strength of the study. The findings help confirm the risk of sharing a sleep surface, she said, but the details on characteristics of sleep-sharing environments provide “novel insight into this problem,” she said.
“For basic researchers,” Dr. Haynes said, “it reiterates that most cases of sudden and unexpected infant deaths are exposed to multiple risk factors. It also highlights the role that young infant age and maternal smoking have as risk factors that contribute to biological vulnerabilities in infants.”
The results also give clinicians more information on characteristics of bedsharing families and some of the factors related to bedsharing, including socioeconomic and behavioral factors, she said. She highlighted the higher risk of SUID when drug or alcohol impairment is involved while bedsharing.
“All of this information is really important and helps clinicians shape the safe sleep messages to families,” she said.
The study authors and Dr. Haynes report no relevant financial relationships.