Studies have shown strong association between infant bed sharing and SIDS.

Although infants who sleep in a bed with an adult are at greater risk for accidents or sudden infant death syndrome, a government-sponsored study shows it happens more often than it used to, especially common among black and Hispanic families.

Studies have shown strong association between infant bed sharing and SIDS, noted the background information for a new study, published online this week in JAMA Pediatrics. The study author, Dr. Eve R. Colson of Yale University School of Medicine, noted that the American Academy of Pediatrics suggests infants sleep in their own bed in the same room with their parents, but not in the same bed.

The research was based on data collected from 18,986 people in the National Infant Sleep Position Study, using phone surveys in 48 states, conducted yearly. Most of the respondents were mothers of infants. More than half were 30 or older, college educated and had incomes of at least $50,000. Four out of five participants were white.

The number of infants sharing beds more than doubled from 6.5 percent in 1993 to 13.5 percent in 2010. Among black and Hispanic families, it increased throughout the study period, while for white families it increased until the year 2000, but not thereafter.

The number of black infants co-sleeping with adults rose from 21.2 percent to 38.7 percent over the entire study period, the highest in the study. For Hispanic infants, it increased from 12.5 percent to 20.5. percent.

For white infants, in 1993 it was 4.9 percent, up to 9.1 percent in 2010.

"We found that black infants, who are at highest risk of sudden infant death syndrome and accidental suffocation and strangulation in bed, share a bed most often. Compared with white infants, black infants are 3.5 times more likely to share a bed," Colson and her colleagues wrote.

An article in USA Today said that "caregivers who perceived physicians' attitude as against sharing a bed were about 34 percent less likely to report that the infant usually shared a bed than were caregivers who received no advice."

Infants were also more likely to share a bed if the household income was less than $50,000 compared to those in a higher income range. Fewer families co-slept in the Midwest, compared to the West and South. Co-sleeping was also more common with infants up to age 15 weeks, compared to older, and with being born too early, compared to full-term. The researchers said they hoped that identifying factors associated with sharing will lead to ways to change behaviors.

Confounding the issue is the fact that another recent multi-center study published in JAMA Pediatrics shows that when mom and baby sleep together, baby is more apt to breastfeed longer, compared to babies who sleep separately.

According to a report in the Los Angeles Times, the "durations of any and exclusive breastfeeding were longest in the often bed sharing group, and shortest in the rare and non-feeding groups." Babies who slept in infant co-sleepers attached at bedside were not considered to be bed sharing, it said.

The benefits of breastfeeding are well documented and include health and developmental benefits, money savings and more. Ironically, breastfeeding is also associated with lower risk of SIDs. But given that co-sleeping can increase that risk, the authors of that study call for strategies to promote breastfeeding without increasing the incidence of bed sharing.

Not everyone agrees the practice of bed sharing is dangerous. In an editorial in the same issue of JAMA Pediatrics, Dr. Abraham B. Bergman, Harborview Medical Center in Seattle, said, "I find the report disquieting because evidence linking bed sharing per se to the increased risk for infant death is lacking."

He said that the campaign against bed sharing stems from recommendations from the American Academy of Pediatrics. "When condemning a widespread cultural practice, the supporting data should be clear," he wrote. "The studies cited to support the AAP's position share a common flaw: nonuniform and unverifiable information on the cause of death."

Other studies, including an international one by German researchers, found there is a link between SIDs and adults sleeping with infants. That risk is especially strong with parents who smoke and with very young infants, younger than 3 months of age, it said.

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