SIDS may involve deficit of brain chemical

Two decades ago, medical experts began urging new parents to place infants on their backs to sleep because studies showed that infants who slept on their stomachs had higher rates of Sudden Infant Death Syndrome. The "Back to Sleep" campaign was highly successful, leading to a decline of SIDS by almost 40%.

However, SIDS still occurs and the overall SIDS rate has plateaued over the last decade as researchers struggle to understand why babies continue to die.

It appears now that SIDS is a multi-factorial illness that involves low levels of the neurotransmitter serotonin. In a study released Tuesday in the Journal of the American Medical Assn., researchers reported evidence from autopsies of 35 infants who died of SIDS. The analysis showed the infants who died had serotonin levels that were 26% lower compared with normal infants. These babies also had lower levels of another brain substance, an enzyme involved in serotonin production called TPH2.

Based on this evidence, and other studies that have also pointed to a problem with serotonin levels, SIDS appears to be caused by a confluence of factors: the serotonin deficit, a reduction in oxygen supply (such as bedding that blocks the mouth and nose) and the infant's inability to respond.

There is still no method for testing infants on their risk of SIDS. But perhaps this research will prompt ideas for preventing these tragic events.

-- Shari Roan

Photo credit: Francine Orr / Los Angeles Times

One less thing to worry about for infants with flat heads

The “Back to Sleep” campaign is credited with averting more than 2,000 cases of sudden infant death syndrome each year. But placing infants on their backs instead of their stomachs has caused the rate of deformational plagiocephaly to surge.

At Wake Forest University Medical Center’s North Carolina Institute for Cleft and Craniofacial Deformities, the increase has been “exponential,” according to staffers there. The number of infants who come to the clinic to be treated for deformational plagiocephaly – a fancy way of saying a flat or misshapen head – has grown to 2,000 per year.

The condition isn’t merely cosmetic. Babies can wind up with eyes, ears or teeth that are out of alignment; temporomandibular joint problems; delays in psychological and motor development; and ear infections.

Researchers at the North Carolina clinic wanted to determine whether a diagnosis of deformational plagiocephaly was associated with an increased risk for ear infections. The smushing of the malleable infant skull can shift and shorten the eustachian tube, which links the middle ear to the nasopharynx. If the tube is unable to drain mucus from the middle ear, bacteria can build up and cause ear infections.

The researchers included 1,112 patients who were treated at the clinic over a two-year period. The average age of babies on their first visit was 5.6 months, and most were treated with band helmets.

Overall, 559 patients – or 50.3% – had an ear infection by their first birthday, according to results published today in the Journal of Craniofacial Surgery. That’s about the same as for infants in general, according to data from the Centers for Disease Control and Prevention.

The researchers found that cases were more likely in babies with more severe deformation. For children with an “initial craniofacial asymmetry severity level” of 1 to 3 on a 5-point scale, 48.8% had at least one ear infection. For children with a severity score of 4 or 5, the incidence rose to 53.9%, according to the study. But the difference between the groups wasn’t statistically significant.

Overall, it would seem that parents coping with a diagnosis of deformational plagiocephaly could breathe a sigh of relief, safe in the knowledge that they need not worry about an increased risk of ear infections as well. But the researchers concluded that the loose correlation between degree of deformity and the rate of ear infections be investigated in future studies.

-- Karen Kaplan

Photo: This baby with deformational plagiocephaly isn't necessarily at increased risk for an ear infection. Credit: Cranial Technologies Inc. / Associated Press

Fan use linked to lower risk of SIDS

Having a fan in the room where an infant is sleeping may help decrease the risk of Sudden Infant Death Syndrome, according to research published today.

SIDS deaths have fallen almost 65% from 1992 to 2003 as research has yielded clues on what causes the tragic deaths of seemingly healthy newborns. One of the best prevention measures, studies have shown, is placing babies on their backs to sleep. But SIDS cases still occur, and so have efforts to understand how to prevent them.

The study today in the Archives of Pediatric & Adolescent Medicine analyzed interviews of mothers from 185 infants who died from SIDS and the mothers of 312 infants who were randomly selected as comparisons. The babies who died from SIDS were more likely to have been placed on their stomachs or sides to sleep, did not use a pacifier, were found with bedding or clothing covering their heads, slept on a soft surface or shared a bed with someone other than a parent -- all known risk factors for SIDS. But the study also found that having a fan on during sleep was associated with a 72% decreased risk in SIDS compared to sleeping in a room without a fan. Fan use in warmer rooms (above 69 degrees Fahrenheit) was associated with a 94% decreased risk of SIDS compared with no fan use. Fan use also decreased the risk of SIDS in infants who slept on their stomachs or sides.

Use of a fan may prevent infants from re-breathing exhaled air, which contains carbon dioxide, or from overheating, said the authors of the study, from Kaiser Permanente's Division of Research in Oakland. Putting infants to sleep on their backs appears to offer the strongest protection against SIDS. But, they added: "Use of a fan in the room of a sleeping infant may be an easily available means of further reducing SIDS risk than can be readily accepted by care providers from a variety of social and cultural backgrounds."

The study needs to be confirmed by further research, said Marian Willinger, special assistant for SIDS Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

For more information on preventing SIDS, see the web pages for the National Sudden Infant Death Resource Center, First Candle, and the American SIDS Institute.

-- Shari Roan

Photo credit: Damir Sagolj / Reuters