Original article
Extreme and Conventional Cardiorespiratory Events and Epidemiologic Risk Factors for SIDS

https://doi.org/10.1016/j.jpeds.2007.10.003Get rights and content

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.

Section snippets

Participants

Of the 1082 participants in the CHIME study, the home monitoring records of 306 healthy term; 170 siblings of SIDS infants (SSIDS), 50 of whom were preterm (≤37 weeks postmenstrual age [PMA]); 152 infants with an idiopathic apparent life-threatening event (ALTE), 45 of whom were preterm; and 454 preterm infants of ≤34 weeks gestation were included in the present study. Infants were excluded from the CHIME study if they had any of the following: pneumonia confirmed by chest radiograph; home

Subject Characteristics

Smoking during pregnancy and in the neonatal period was observed in 12% of Asian, 16% of African-American, 32% of Caucasian, 4% of Hispanic, and 24% of other mothers (Table II).

Events in ALTE, SSIDS, and Preterm Infants

In the cohort ≤44 weeks PMA, the ALTE, SSIDS, and preterm infants were at significantly increased risk of at least 1 extreme event compared with healthy term infants. A comparison of SSIDS and ALTE infants with preterm infants revealed that the preterm infants had significantly more events (P = .003). The ROC result for

Discussion

This study supports our first hypothesis, that extreme events are not statistically associated with known SIDS risk factors. An excess of extreme events was not found at the time of night when infants are most likely to die. In contrast, extreme events occurred less often during the early morning, when infants tend to be at higher risk for SIDS. Moreover, Asians, the ethnic group at lowest epidemiologic risk for SIDS, exhibited a tendency toward a higher rate of extreme events.13 Healthy terms

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  • Cited by (0)

    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.

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