Causes, Effects, Statistics, and SIDS; or, Pop in a Pacifier?

Many readers will have come across the idea that the reported increase in autism has as much to do with changed diagnostic categories and changed reporting procedures as it does with any actual changes in this serious mental health disorder. Autism is not the only problem for which changes in definitions and reporting have had an effect on nationwide statistics. Until Kempe and his colleagues formulated their descriptions of child abuse in the early 1960s, little information was available, and injuries that we today would think begged for investigation were recorded as accidental. Do the same issues apply to Sudden Infant Death Syndrome? This is more than an abstract question, because the answer is needed to help us understand what child care methods should be recommended to new parents. (N.B. I do not claim that the answer will be found below; I’m just planning to discuss some factors that are relevant.) Because there are probably multiple causes for SIDS, it’s important to have an accurate measure that will let us know whether a specific factor actually makes a difference.

As parents and many non-parents will know, the official position of the U.S. government is that SIDS rates have been and will continue to be reduced when parents follow the advice given by the Back to Sleep program (www.nichd.nih/gov/sids/). This parent education program concentrates on baby sleeping position as the primary factor in SIDS, with the prone (tummy down) position rejected in favor of the supine (on back) sleeping position. Beginning in the 1990s, this program was diametrically opposed to the earlier conventional wisdom, which was that babies should lie in the prone position because that would make it easier for them to clear their airways if they should spit up or vomit. It was a hard sell to parents, because they were inclined to do what they were accustomed to and what was advised by their own parents and other experienced caregivers. Nevertheless, more and more (although not all) of parents, doctors, and nurses have bought into the Back to Sleep program.

Proponents of Back to Sleep have pointed out that the SIDS rate has dropped since the program began, and this is certainly true.  However, it is also true that the rate had been on the way down before the program began, and its trajectory has not changed much. It is also true that ascertaining that an infant death was caused by SIDS is not a very simple matter. There are alternative categories for deaths of this type. They may be classed as “accidental suffocation and strangulation in bed” or as “cause/unknown/unspecified”. (“Murder” is another possibility, but that’s a different story.)  As SIDS rates declined around the beginning of the present century, the rates of deaths in those other categories actually increased (see Shapiro-Mendoza, Tomashek, Anderson, & Wingo, American Journal of Epidemiology, 2006, Vol. 173, pp.  762-769).

More research in this area has yielded information about the complexities of SIDS and underlined the fact that there is no single factor at work here. For example, Li et al (American Journal of Epidemiology, 2003, pp. 446-455) interviewed a sample of mothers whose infants had died suddenly and unexpectedly, and found that one factor appeared to be being put to sleep in an unaccustomed position. Babies who had been used to sleeping in the supine position were more likely to die when placed in prone than those who were accustomed to lie in the prone position, suggesting that parents need to be in agreement with each other about sleeping position, as well as in agreement with child care staff or grandparents who may decide to use the prone position that they find more familiar.

Further research by the same authors (Li et al., British Medical Journal, 2006, issue 7532, pp. 18-21) brought up a new and potentially important factor in SIDS causation and prevention. This was the use of pacifiers (or “dummies”) --  a practice much hated and condemned by many parents and amateur advisers. Li et al interviewed mothers of babies who had died from SIDS and compared them to mothers of healthy babies who were matched on measures like age and socioeconomic status. They found that although the risk of SIDS was significantly greater for babies who slept in the prone position and did not use pacifiers, there was no difference in risk of SIDS for the pacifier-using babies, no matter which position they slept in.

In spite of the concerns raised about changes in the SIDS rate, and in spite of the demonstrated effect of factors other than position, we continue to have a public health emphasis on the supine position as the best intervention for SIDS prevention. But isn’t it time that other factors were emphasized as well? How about a Pop in a Pacifier program--  or would that be too shocking for people who hate to see the pacifier habit begin?  How about a Talk to Your Child Care Helpers program--  highly relevant, when so many babies in the U.S. have multiple caregivers? It’s not even certain that sleeping position is the major factor in SIDS, so why put all the public health eggs in this one basket?