Introduction Acute respiratory infections (ARIs) in infancy may have a long-term impact on the developing respiratory system. We planned a prospective cohort study to determine the impact of ARI during infancy on the pulmonary function test indices at 3 years of age.
Methods A cohort of normal, full-term newborns were followed up 6 monthly and during ARI episodes. Infant pulmonary function tests (IPFTs) were performed at baseline and each follow-up visit using tidal breathing flow-volume loop, rapid thoracoabdominal compression (RTC) and raised volume RTC manoeuvres. During each ARI episode, nasopharyngeal aspirates were tested for respiratory pathogens by real-time PCR.
Results We screened 3421 neonates; 310 were enrolled; IPFT was performed in 225 (boys: 125 (55.6%)) at 3 years. During infancy, 470 ARI episodes were documented in 173 infants. At 3 years, children with history of any ARI episode during infancy had lower forced expiratory volume in 1 s (FEV1.0), forced expiratory volume in 0.75 s (FEV0.75), forced expiratory volume in 0.5 s (FEV0.5), forced expiratory flow between 25% and 75% of FVC (FEF25–75), and maximal expiratory flow at 25% of FVC (MEF25) as compared with those without any ARI episode during infancy. The ratio of tidal expiratory flow (TEF) at 25% or 50% of tidal expiratory volume to peak TEF (TEF50 or TEF25/peak TEF) at 3 years was significantly increased in children who had ARI in infancy.
Conclusions ARI during infancy is associated with impaired pulmonary function indices such as increased resistance and decreased forced expiratory flow and volume at 3 years of age.
- acute respiratory tract infection
- pulmonary function test
- respiratory syncytial virus
- tidal volume
- forced expiratory volume
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Contributors SKK and RL: conceptualised and designed the study, developed protocol and drafted the manuscript: PK and SR: enrolled patients, collected and analysed data, reviewed literature and prepared initial draft of the manuscript. AM: collected and analysed data, reviewed literature and manuscript preparation. GRM, AK: laboratory assays, data analysis, and manuscript preparation. KRJ: data analysis, reviewed literature and manuscript preparation. All authors had critically revised and approved the final version of the manuscript.
Funding The study was funded by the Department of Biotechnology (DBT), Government of India.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.
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