Respiratory morbidity, atopy and asthma at school age in preterm infants aged 32–35 weeks
Little is known about respiratory morbidity and asthma risk in preterm infants (PTIs) with a gestational age (GA) over 32 weeks. This was a prospective study carried out from birth to 7–8 years, comparing two groups: (a) PTIs (GAs 32 weeks + 1 day to 35 weeks + 0 days, without comorbidities) and (b) full-term infants (FTIs; GA ≥ 37 weeks). Risk and protective factors for bronchiolitis and asthma were identified. A total of 232 children (116/group) were included. Sixty-six (56.9%) PTIs and 43 (37.1%) FTIs presented bronchiolitis (p = 0.002). Recurrent wheezing was 52 (44.8%) on PTIs versus 36 (31.0%) on FTIs (p = 0.03). Asthma at school aged was 27 (23.3%) on PTIs and 8 (6.9%) on FTIs (p = 0.020). Asthma risk factors were only detected in group A.
What is known:
• In recent decades, there has been a significant increase in the birth of premature babies and consequently, also in the pathologies secondary to the prematurity: a greater number of complications and disorders related to the development and maturation of many organs and systems, especially the respiratory system. Several studies, especially in full-term infants and very preterm infants, have tried to elucidate the risk factors that may influence the development of persistent or chronic respiratory problems such asasthma, but little is known about the aetiology of these disorders in the late or moderate preterm infants. Inthis group of children, the role played by certain factors (early use of antibiotics, chorioamnionitis, smokeexposure, paternal asthma, etc.) on late respiratory morbidity, or asthma, is inconclusive.
• Moderate-to-late preterm infants are more predisposed to developing recurrent wheezing/asthma and should adopt control measures.
What is new:
• Our work provides data related to little-understood aspects of respiratory diseases in this group of late or moderate preterm infants (gestational age between 32 weeks plus 1 day and 35 weeks plus 0 days), by monitoring their evolution from birth to 7–8 years of age, compared with another group of full-term newborns. We aimed to establish the prevalence of bronchiolitis and recurrent wheezing in these children during their first years of life.
• The prevalence of school-aged asthma and the risk factors for contracting it were also investigated.
KeywordsPrematurity Asthma Atopy Risk factors Bronchiolitis Recurrent wheezing
Body mass index
Fractional exhaled nitric oxide
Forced expiratory volume in the first second
Forced vital capacity
Global Initiative for Asthma
International Study of Asthma and Allergies in childhood
In vitro fecundation
Modified asthma predictive index
Maximal expiratory flow rate at 25–75% of forced vital capacity
Number of responses
Parts per billion
Respiratory syncytial virus
Preschool Children’s Quality of Life Questionnaire
The authors would like to acknowledge the collaboration of the neonatal service and the paediatric nursing staff at the Hospital Clínico de Valencia. The authors acknowledge the collaboration of Alce Ingeniería (Las Rozas, Madrid, Spain) in the initial development of the project support systems and statistical analysis.
J M-A, MD, and A E-M, MD: conceived and designed the study, drafted the initial manuscript and approved the final manuscript as submitted.
T R-R, MD, and S C-C, MD: carried out the initial analyses, reviewed and revised the manuscript and approved the final manuscript as submitted.
All the authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
Compliance with ethical standards
The period between birth and 3 years of age was already collected in our centre (Infantile Pneumology and Cystic Fibrosis Unit of the Hospital Clínico Universitario Valencia), as part of a national multicentre study (SAREPREM 3235) in which we participated as researchers, and which was approved by the Ethics and Clinical Research Committee of the Donostia Hospital, in San Sebastián, and was carried out under the ethical postulates of the Helsinki Declaration and the guidelines of the Spanish Society of Paediatric Pneumology (SENP).
After its completion, it was proposed to extend it with the follow-up of the children included in our centre until the age of 6–8 years, and was approved by the Ethics Committee of the Hospital Clínico Universitario de Valencia.
Conflict of interest
The authors declare that they have no conflict of interest.
All parents signed the written informed consent.
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