Extreme and Conventional Cardiorespiratory Events and Epidemiologic Risk Factors for SIDS

Received 20 February 2007; received in revised form 18 September 2007; accepted 1 October 2007. published online 10 December 2007.

Objective

To test the hypotheses that there is a lack of correlation between extreme events and epidemiologic risk factors for sudden infant death syndrome (SIDS), and if conventional events are normal, their numbers should increase once a circadian decrease in breathing rate is established. In addition, the number of events should decrease with maternal smoking.

Study design

Three outcome variables were derived from the Collaborative Home Infant Monitoring Evaluation (CHIME) of 1082 infants: (1) at least 1 extreme event lasting ≥30 seconds, (2) at least 1 conventional event lasting ≥20 seconds, and (3) being part of the 50% of infants with the most events.

Results

Multivariate logistic regression analyses found that extreme events were not statistically associated with any known SIDS risk factors and occurred less often during the early morning. Healthy term infants had significantly fewer of these events compared with preterm infants, subsequent siblings of infants with SIDS, and infants with an apparent life-threatening event, a finding that was not evident after 43 weeks (3 weeks postterm). Conventional events increased during the night, whereas maternal smoking was associated with a decrease in conventional events. Apneic episodes persisting for ≥40 seconds occurred in 1.8% of the infants.

Conclusions

Extreme events are associated with immaturity and do not seem to be immediate precusors of or causally related to SIDS.

Abbreviations: ALTE, Apparent life-threatening event, AOI, Apnea of infancy, CHIME, Collaborative Home Infant Monitoring Evaluation, CI, Confidence interval, OR, Odds ratio, PMA, Postmenstrual age, ROC, Receiver operating characteristic curve, SIDS, Sudden infant death syndrome, SSIDS, Subsequent sibling of sudden infant death syndrome

a Division of Neonatal Medicine and Biostatistics, LAC + USC Medical Center, Women's and Children's Hospital, Los Angeles, CA

b Children's Hospital Los Angeles, Los Angeles, CA

c Keck School of Medicine, University of Southern California, Los Angeles, CA

d New York Presbyterian Hospital-Weill Cornell Medical Center, New York, NY.

Reprint requests: Toke Hoppenbrouwers, PhD, Room 9L19, Women and Children's Hospital, LAC + USC Medical Center, 1240 Mission Road, Los Angeles, CA 90033.

Supported by the National Institute of Child Health and Human Development (grants HD 29067, HD 29071, HD 28971, HD 29073, HD 29056, and HD 34625) and a generous donation from the Orange County Guild for Infant Survival.

PII: S0022-3476(07)00959-6

doi:10.1016/j.jpeds.2007.10.003

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