Increasing public awareness of the prone sleeping position, maternal s
moking and overheating as potentially avoidable risk factors for the s
udden infant death syndrome (SIDS) has been accompanied by a dramatic
reduction in mortality. The results of two population based studies of
SIDS in Avon are compared; the first one occurred before these risk f
actors were widely known and during the second study there was a gradu
al increase in publicity. Between the studies the prevalence of prone
sleeping in the control populations fell significantly from 60% to 28%
and almost all of the reduction in SIDS mortality (3.5 to 1.7 per tho
usand live births) could be attributed to this change. Other changes w
ere also found: the seasonal pattern of incidence was lost, the propor
tion of expreterm babies increased and the male predominance was accen
tuated. The relative importance of smoking and bottle feeding appeared
to increase whereas the odds ratios for heavy wrapping and overnight
heating were no longer significantly elevated. Small numbers limit the
significance of these individual variations but demonstrate that chan
ges are occurring. Local and national public health compaigns have bee
n launched in the UK and abroad to encourage infant care practices tha
t reduce the risk of SIDS. Monitoring the effectiveness of these campa
igns is important and may allow new risk factors to be identified whic
h could in turn be targeted in future preventative campaigns. Signific
ant reductions in mortality have followed these initial campaigns but
in order to maintain them the message must be regularly renewed using
an appropriate approach and effective channels of communication to tar
get high risk families within the community.