Association of transient tachypnea of the newborn and childhood asthma

Objective: To determine if transient tachypnea of the newborn (TTN) is independently associated with childhood asthma. Methods: The sampling frame was a computerized database on 18,379 term infants born between January 1, 1996 and December 31,2000 in an urban tertiary care hospital. This was a case-control study nested in a cohort of all term newborns who were subsequently diagnosed with asthma (n = 2137) and a similar number of birthday-matched controls. The International Classification of Diseases, Ninth Revision code was used to identify the infants with TTN and those who developed asthma. Logistic regression was used to adjust for potentially confounding variables. Stratified multivariate analysis was undertaken on subgroups to assess possible effect modification by factors known to influence the incidence of asthma: race, gender, domicile, and maternal asthma. Results: After adjustment for potential confounding, TTN was significantly associated with the diagnosis of childhood asthma (adjusted OR 1.50, 95% Cl: 1.13-1.99; P=0.0052). The association of TTN and asthma was statistically strongest among male infants, especially among males whose mothers lived at an urban address, males of non-white race, and males whose mothers did not have asthma. The pattern of association of TTN and asthma was similar for infants diagnosed with asthma once compared with those diagnosed with asthma recurrently. Conclusion: TTN was independently and significantly associated with the subsequent diagnosis of childhood asthma, especially among male infants. TTN may be a marker of deficient pulmonary function reflecting inherited susceptibility to asthma.