Fewer U.S. babies are dying from, but certain minorities remain at greater risk, a new study finds.
Researchers who tracked cases offrom 1995 through 2013 found that American Indian/Alaska Natives and blacks had double the rate in 2013 compared to whites.
That was so despite a significant decline in SIDS rates among blacks during the study period, the researchers found.
Why these disparities exist isn't clear. Dr. Alessandro Acosta, a neonatologist at Nicklaus Children's Hospital in Miami, speculated that socioeconomic, cultural or even biological differences may be to blame.
"This is a novel study," due to the breakdown in statistics from different groups, said Acosta, who wasn't involved in the research.
"We have well documented that thedecreased sharply after the 'Back to Sleep' campaign," said study leader Sharyn Parks.
"What we didn't know is what sorts of patterns were underlying it," said Parks, an epidemiologist at the U.S. Centers for Disease Control and Prevention.
For this study, Parks and her team tracked the rates of sudden unexpected deaths over nearly two decades, looking separately at different racial and ethnic groups.
Following a decline in the late 1990s, the overall rate remained stable after 2000 -- about 93 cases out of every 100,000 live births, the researchers found.
Rates changed little for American Indian/Alaska Natives or for whites. Hispanic and Asian/Pacific Islander infants had lower rates of sudden death compared to whites for the entire study period, with Asian/Pacific Islanders showing the greatest decline.
Most deaths happened at about 1 or 2 months of age, and girls were less likely than boys to die of a sudden death, the study found.
The study did not explain the disparities. But, Parks speculated that modifiable risk factors, such as putting a baby to sleep on the stomach or on soft bedding, could help explain some of the findings.
It's also possible that public health campaigns aren't reaching certain population groups, the study authors said.
And some experts suggest that some infants are simply more vulnerable to sudden infant death, for reasons not yet fully understood.
Acosta tells parents to be especially vigilant the. "We see most of the episodes in newborn to 4 months," he said. However, he added that older infants can succumb as well.
Advice to parents?
"Always put your baby to sleep on his back," Acosta said. He also tells parents to follow the additional tips in the Back to Sleep campaign. These include not using soft bedding and not bringing an infant into bed with you.
Put infants to sleep on a firm, not soft, surface, Parks added. Also, make sure anyone caring for the infant, such as, is up to date on the , she said.
The study was published online May 15 in Pediatrics.