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