What do fans and ear hair have in common? Turns out both may play a role in the risk of Sudden Infant Death Syndrome (SIDS.)

While the incidence of SIDS has decreased in recent years (due in large part to Back to Sleep campaigns), SIDS remains the leading cause of death in infants 1 month to 1 year of age.

First the ear hair
Daniel Rubens, MD has long believed that there was a piece missing in our understanding of how the body controls breathing. He theorized that the missing piece might be the tiny hairs in the inner ear. To test his theory, he conducted a case-controlled study of 31 Rhode Island babies who subsequently died of SIDS and compared them to 31 babies that survived the first year of life. (Rhode Island was one of the first states to test the hearing of all newborns.) Rubens found that all of the 31 babies who died of SIDS showed consistently lower scores across three sound frequencies when compared to babies in the control sample.

The hearing deficit can be explained by damage to the fine hairs in the inner ear. But if Rubens is right, and some of the tiny hairs warn the brain about carbon dioxide (CO2) levels in the blood, damage to the hairs could increase the risk for SIDS.

The brain normally responds to an increase in CO2 levels by stimulating the body to breath faster. If the warning mechanism is damaged, the brain doesn’t receive a signal and the baby suffocates from lack of oxygen.

While the results are preliminary, they raise the possibility that hearing tests might be used to identify newborns who are at greater risk for SIDS.

Now the fan
Kimberly Colema-Phox, MPH and colleagues conducted a population-based, case-controlled study to determine whether room ventilation, defined as use of a fan or an open window, reduced the risk for SIDS. Study participants included mothers of 185 infants who had died of SIDS, and 312 infants who survived the first year.

Results showed that use of a fan while sleeping reduced the risk of SIDS by 72 percent. The benefit was even greater when babies slept in environments considered unsafe e.g. rooms with warmer temperatures, sharing a bed with an individual other than a parent.

Why does use of a fan make a difference? One theory is that the fan causes air movement that disperses the CO2 exhaled by the baby around the room so the baby can’t reinhale it.

The take home message for expectant parents: Talk with your baby’s health care provider about a hearing test, and considering adding a fan to your baby registry.