title: Seasonal Timing of Infant Bronchiolitis, Apnea and Sudden Unexplained Infant Death.
abstract: Rates of Sudden Unexplained Infant Death (SUID), bronchiolitis, and central apnea increase in winter in temperate climates. Though associations between these three conditions are suggested, more work is required to establish if there is a causal pathway linking bronchiolitis to SUID through inducing central apnea. Utilizing a large population-based cohort of infants studied over a 20-year period (n = 834,595, from birth years 1989-2009)), we analyzed ecological associations between timing of SUID cases, bronchiolitis, and apnea healthcare visits. Data were analyzed between 2013 and 2015. We used a Cox Proportional Hazards model to analyze possible interactions between maternal smoking and maternal asthma with infant bronchiolitis on time to SUID. SUID and bronchiolitis both occurred more frequently in winter. An increase in bronchiolitis clinical visits occurred within a few days prior to apnea visits. We found a temporal relationship between infant bronchiolitis and apnea. In contrast, no peak in SUID cases was seen during peaks of bronchiolitis. Among those without any bronchiolitis visits, maternal smoking was associated with an increased risk of SUID: Hazard Ratio (HR) of 2.38 (95% CI: 2.11, 2.67, p-value <0.001). Maternal asthma was associated with an increased risk of SUID among infants with at least one bronchiolitis visit: HR of 2.40 (95% CI: 1.04, 5.54, p-value = 0.04). Consistent trends between bronchiolitis, apnea, and SUID were not established due to small numbers of SUID cases. However, interaction analysis revealed potential differential associations of bronchiolitis and SUID by maternal smoking, maternal asthma status.
authors.affiliation: Department of Health Science, Brigham Young University, Provo, Utah, United States of America.
authors.forename: Chantel D
authors.initials: CD
authors.lastname: Sloan
authors.affiliation: Center for Asthma Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Tebeb
authors.initials: T
authors.lastname: Gebretsadik
authors.affiliation: Center for Asthma Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Christian
authors.initials: C
authors.lastname: Rosas-Salazar
authors.affiliation: Center for Asthma Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Pingsheng
authors.initials: P
authors.lastname: Wu
authors.affiliation: Center for Asthma Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Kecia N
authors.initials: KN
authors.lastname: Carroll
authors.affiliation: Department of Health Policy,Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Edward
authors.initials: E
authors.lastname: Mitchel
authors.affiliation: Department of Pediatrics, Pediatric Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Anderson
authors.affiliation: Center for Asthma Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Emma K
authors.initials: EK
authors.lastname: Larkin
authors.affiliation: Center for Asthma Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.|Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Tina V
authors.initials: TV
authors.lastname: Hartert
mesh_terms: D000328:Adult; D001049:Apnea / Q000453:epidemiology* / Q000209:etiology; D001249:Asthma / Q000453:epidemiology; D001988:Bronchiolitis / Q000453:epidemiology* / Q000209:etiology; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009035:Mothers; D012621:Seasons; D013398:Sudden Infant Death / Q000453:epidemiology*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects; D055815:Young Adult
chemical_list: D014028:Tobacco Smoke Pollution