Pre-existing High-Risk Conditions in Case-Patients and Controls (Percentage of Case-Patients or Control Subjects With Specific Condition of All Case-Patients or Control Subjects With Any High-Risk Condition)

ConditionNumber of Case-Patients (%)Number of Control Subjects (%)
Prematurity (≤36 weeks’ gestational age)
    Required mechanical ventilation2 (6)0 (0)
    Required O2 but not mechanical ventilation5 (16)3 (38)
    No O2 or mechanical ventilation14 (44)4 (50)
21 (66)7 (88)
Lung disease
    Congenital lung disease (eg, diaphragmatic hernia, pulmonary hypoplasia) requiring surgery or treatment3 (9)0 (0)
    Previous mechanical ventilation (other than for prematurity)1 (3)0 (0)
4 (12)0 (0)
Significant congenital or acquired heart condition6 (19)1 (12)
Other systemic conditions*4 (12)0 (0)
Overall total328
  • * Other conditions include children with Down syndrome, traumatic encephalopathy, congenital hypothyroidism, and low birth weight at full-term infant.

  • ** Subtotals may add to more than total as 1 infant may be classified in >1 major disease category.