Lung Function at 8 and 16 Years After Moderate-to-Late Preterm Birth: A Prospective Cohort Study

BACKGROUND AND OBJECTIVE: Knowledge regarding lung function after moderately preterm birth is limited. We therefore investigated lung function at early school age and adolescence among children born moderately preterm. METHODS: Data were used from the Swedish prospective birth cohort BAMSE (Swedish abbreviation for Children, Allergy, Milieu, Stockholm, Epidemiology study; N = 4089), with a 4.8% prevalence of moderate to late preterm birth defined as a gestational age of 32 to 36 weeks. Participants underwent spirometry at ages 8 and 16 years, and impulse oscillometry additionally at age 16 years. In total, 2621 children (149 preterm and 2472 term) provided lung function data. RESULTS: At age 8 years, adjusted forced expiratory volume in 1 second was lower in preterm female subjects (–64 mL [95% confidence interval (CI): –118 to –10]) compared with term female subjects but not in preterm male subjects. At age 16 years, both genders in the preterm group demonstrated lower forced expiratory volume in 1 second (female subjects: –116 mL [95% CI: –212 to –20]; male subjects: –177 mL [95% CI: –329 to –25]) compared with the term group. For the preterm group, impulse oscillometry demonstrated higher adjusted resistance at 5 Hz (female subjects: 31.3 Pa·L –1 ·s −1 [95% CI: 6.3 to 56.3]; male subjects: 34.9 Pa·L –1 ·s −1 [95% CI: 12.0 to 57.7]) and frequency dependence of resistance (resistance at 5 and 20 Hz) for male subjects (20.9 Pa·L –1 ·s −1 [95% CI: 9.8 to 31.9]) compared with the term group. CONCLUSIONS: Measures of airway function assessed in adolescence were reduced in children born moderate to late preterm, and no catch-up in lung function between ages 8 and 16 years was observed.