Effect of late preterm birth on longitudinal lung spirometry in school age children and adolescents

Abstract

Background Rates of preterm birth have increased in most industrialised countries but data on later lung function of late preterm births are limited. A study was undertaken to compare lung function at 8e9 and 14e17 years in children born late preterm (33e34 and 35e36 weeks gestation) with children of similar age born at term ($37 weeks gestation). Children born at 25e32 weeks gestation were also compared with children born at term. Methods All births from the Avon Longitudinal Study of Parents and Children (n¼14 049) who had lung spirometry at 8e9 years of age (n¼6705) and/or 14e17 years of age (n¼4508) were divided into four gestation groups. Results At 8e9 years of age, all spirometry measures were lower in the 33e34-week gestation group than in controls born at term but were similar to the spirometry decrements observed in the 25e32-week gestation group. The 35e36-week gestation group and term group had similar values. In the late preterm group, at 14e17 years of age forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC) were not significantly different from the term group but FEV 1 /FVC and forced expiratory flow at 25e75% FVC (FEF 25e75% ) remained significantly lower than term controls. Children requiring mechanical ventilation in infancy at 25e32 and 33e34 weeks gestation had in general lower airway function (FEV 1 and FEF 25e75 ) at both ages than those not ventilated in infancy. Conclusions Children born at 33e34 weeks gestation have significantly lower lung function values at 8e9 years of age, similar to decrements observed in the 25e32-week group, although some improvements were noted by 14e17 years of age.

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

“…Although reports of lung function at school age and adolescence are sparse in subjects born moderate to late preterm, a study by Kotecha et al 12 reported similar results as in our study, with significantly lower lung function at 8 to 9 years of age for children born after 33 to 34 weeks of gestation, compared with term control subjects. However, they found no significant negative effects among those born after 35 to 36 weeks of gestation.…”

“…Quality control was performed at the time of examination by visual inspection of the waveforms. Given that coherence, which is a measure of testing reliability, was >0.80 at 10 Hz, the mean value of resistance at 5 Hz (R 5 ), resistance at 20 Hz (R 20 ), frequency dependence of resistance (ie, R [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], and reactance area (AX) were used for analysis. AX may boost the assessed response inappropriately compared with the R 5-20 response because it multiplies 2 partly independent reactions of the airways.…”

“…[5][6][7][8][9][10][11] Few studies are available on lung function at school age and adolescence in this group, however, and the results are somewhat conflicting. 12,13 Furthermore, although spirometry is a well-established method to assess lung function by measuring expiratory flow rates and volumes, other lung function techniques aiming to assess peripheral airway function and mechanics, such as forced oscillation, have been shown to be more sensitive than spirometry for detection of airway obstruction in children with lung disease, including follow-up studies of children born very preterm. [14][15][16][17][18] We hypothesized that being born moderate to late preterm would have a negative effect on lung function through childhood and adolescence.…”

New reference equations to improve interpretation of infant lung function

“…Results from six infants born between 36 and 37 weeks gestation were however included as there is no evidence of changes in subsequent lung function at such gestations. 35 Ideally, we would have studied a multi-ethnic group of children to ascertain the potential impact of ethnic origin and allow application of these reference equations to all infants presenting for lung function tests. This was beyond the scope of the present study, especially as many of the infants had been recruited as controls when studying infants with Cystic Fibrosis, a disease predominantly affecting those of White European descent.…”

Evaluation of pulmonary functions in preschool children born late-preterm

“…The two main factors that constitute impedance are resistance (R) and reactance (X). It is measured between certain frequencies (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). When R and X are measured at 5 Hz, they are named R5 and X5.…”