“Back To Sleep” message took longer to reach deprived areas

A study of 24 years of cot death rates (sudden infant death syndrome, or SIDS) in Scotland has shown major differences in the success of the “Back To Sleep” campaign, depending on where women lived. The study is published in today’s British Medical Journal Online (http://group.bmj.com/).

SIDS was relatively common in the 1980s, affecting about 1 in 500 liveborn infants. Recognition of the importance of sleeping position, however, subsequently led to a dramatic fall in the rates of SIDS throughout the world. At the moment, fewer than one in every 2,000 babies in the UK dies from SIDS.

Today’s study demonstrates that rates of SIDS changed dramatically in Scotland around the time of the “Back to Sleep” campaign (November 1991). This campaign, which became a cornerstone of the successful drive to change babies’ sleeping position and thereby put them at less risk, was so-named because it recommended the placing of healthy babies on their backs to sleep.

A team of researchers, led by the University of Cambridge, analysed nationally collected data from Scotland to examine whether there was a relationship between socioeconomic deprivation and SIDS, other causes of infant death and stillbirth between the period 1985 and 2008. This revealed major differences in the rate at which Back To Sleep proved effective, according to socioeconomic deprivation.

Among women living in areas of low deprivation, the decline in SIDS started in 1990 and rates fell to a stable, low level by 1993. The study reveals, however, that Back To Sleep took much longer to impact areas of high deprivation, where the rate of SIDS began to decline in 1992 and took more than a decade, and possibly as many as 15 years, to reach a low and stable rate.

Although ultimately rates of SIDS fell in all communities, these differences led to a big change in “relative disparity” (the relative risk in the most deprived communities, compared with the least deprived), from 2-fold before the campaign, to up to 10-fold after the campaign. During the same 24 year period, there were no comparable changes in the relative risk of stillbirth, or other causes of infant death.

Interestingly, rates of SIDS among women living in areas of low deprivation had also already fallen dramatically before the “Back To Sleep” campaign began. The most plausible explanation for this may be the dissemination of the results of research studies in the press at the time. For example, a key UK study showing that babies were at lower risk when lying on their backs was published in July 1990, and the results reported in several national broadsheets after its publication in the BMJ. SIDS rates dramatically declined for babies born in 1990 among families living areas of low deprivation.

Professor Gordon Smith, from the Department of Obstetrics and Gynaecology at the University of Cambridge, said: “Ultimately, Back To Sleep was a huge success and helped to stimulate an abrupt decline in the rate of sudden infant death syndrome all over the world. Clearly, however, it was much slower where deprivation was high. The importance of this study is that it shows that any future campaigns to modify environmental risk factors for stillbirth and infant death should be carefully designed so that the message is delivered to people living in areas of high deprivation more effectively.”

The full study, Trends in socioeconomic inequalities in risk of sudden infant death syndrome, other causes of infant mortality, and stillbirth in Scotland, will be available at http://group.bmj.com/.