According to the Los Angeles County Department of Public Health, approximately 8% of children less than 18 years of age suffer from asthma. According to a new study published online September 12 in the journal Pediatrics, late-preterm birth is linked to asthma in early childhood. “Infants born late preterm (34–36 weeks of gestation) are at increased risk for respiratory morbidity in the neonatal period,” wrote Neera K. Goyal, MD, from the Department of Pediatrics, Children’s Hospital of Philadelphia in Philadelphia, Pennsylvania, and colleagues. “Few studies have focused on the possible associations between late-preterm birth and long-term respiratory outcomes such as asthma.” The goal of the study was to examine the association of late-preterm birth with asthma severity among young children, using electronic health record data from 31 practices affiliated with an academic medical center. The study group was comprised of 7,925 infants born in 2007 at 34 to 42 weeks of gestation and monitored from birth to 18 months; 7% were late-preterm gestation (34 – 36 weeks), and 21% were low-normal gestation (37 – 38 weeks). The effect of late-preterm and low-normal gestation vs. term gestation (39 – 42 weeks) on diagnoses of asthma and persistent asthma, inhaled corticosteroid use, and numbers of acute respiratory visits was evaluated.
By age 18 months, 8.3% of the study sample had been diagnosed with asthma. For late-preterm gestation vs. term gestation, there were significant increases in diagnoses of persistent asthma and numbers of acute respiratory visits (1.44 times higher). Compared with term gestation, low-normal gestation was associated with increases in asthma diagnoses (1.34 times higher) and inhaled corticosteroid use (1.39 times higher). The authors concluded: “Birth at late-preterm and low-normal gestational ages might be an important risk factor for the development of asthma and for increased health service use in early childhood.”
Limitations of this study were primarily related to regression adjustment for non-randomization. Data were lacking on certain prenatal and postnatal risk factors; there might have been errors in International Classification of Diseases, Ninth Revision, coding that led to misclassification bias; and follow-up was limited to age 18 months.
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