Sudden infant death syndrome
Rachel Y Moon, Rosemary S C Horne, Fern R Hauck
Lancet 2007; 370: 1578–87 Goldberg Center for Community Pediatric Health, Children’s National Medical Center and George Washington University School of Medicine and Health Sciences, Washington, DC, USA (R Y Moon MD); Ritchie Centre for Baby Health Research, Monash Institute for Medical Research, Monash University, Melbourne, Australia (R S C Horne PhD); and Departments of Family Medicine and Public Health Sciences, University of Virginia School of Medicine Charlottesville, Virginia, USA (F R Hauck MD) Correspondence to: Rachel Y Moon, Children’s National Medical Center, Michigan Avenue NW, Washington, DC 20010, USA firstname.lastname@example.org
Despite declines in prevalence during the past two decades, sudden infant death syndrome (SIDS) continues to be the leading cause of death for infants aged between 1 month and 1 year in developed countries. Behavioural risk factors identiﬁed in epidemiological studies include prone and side positions for infant sleep, smoke exposure, soft bedding and sleep surfaces, and overheating. Evidence also suggests that paciﬁer use at sleep time and room sharing without bed sharing are associated with decreased risk of SIDS. Although the cause of SIDS is unknown, immature cardiorespiratory autonomic control and failure of arousal responsiveness from sleep are important factors. Gene polymorphisms relating to serotonin transport and autonomic nervous system development might make aﬀected infants more vulnerable to SIDS. Campaigns for risk reduction have helped to reduce SIDS incidence by 50–90%. However, to reduce the incidence even further, greater strides must be made in reducing prenatal smoke exposure and implementing other recommended infant care practices. Continued research is needed to identify the pathophysiological basis of SIDS.
Sudden infant death syndrome, or SIDS, is deﬁned as “the sudden death of an infant under one year of age, which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history”.1 Despite declines in SIDS rates following risk reduction campaigns, SIDS continues to be the leading cause of death for infants aged between 1 month and 1 year in developed countries. Currently, Japan and the Netherlands have the lowest reported SIDS rates, at 0·09 and 0·1 per 1000 livebirths, respectively,2,3 whereas New Zealand has the highest reported SIDS rate in developed countries, at 0·8 per 1000 livebirths.4 The USA and the UK have intermediate SIDS rates of 0·57 and 0·41 per 1000 livebirths, respectively.5,6 In this Seminar, we focus on newer epidemiological and pathophysiological ﬁndings, risk reduction recommendations, and controversies related to some of these recommendations.
of placing infants prone for sleep has decreased 50–90%, and the rate of SIDS has similarly decreased 50–90%. As prone sleeping has become a less common risk factor, new epidemiological risk factors have emerged. We will discuss the epidemiology of SIDS both before and after the decrease in prone sleeping.
SIDS occurs less frequently in the ﬁrst month of life, peaks between 2 and 4 months of age, and decreases thereafter. Around 90% of SIDS deaths happen in the ﬁrst 6 months of life. Boys are more likely to die than girls, at a ratio of 60:40. Despite the overall decline in SIDS worldwide, there are still racial and ethnic disparities. In the USA, infants who are African American, Native American, or Alaska Native have SIDS rates that are two to three times the national average, irrespective of socioeconomic status.7,8 Maoris in New Zealand9 and Aboriginal Australians10–12 are also at higher risk for SIDS. Maoris are six times more likely to die of SIDS than non-Maori New Zealanders.13 Although biological diﬀerences (such as racial diﬀerences in tobacco metabolism14) might...