Effect of acute respiratory infections in infancy on pulmonary function test at 3 years of age: a prospective birth cohort study

Kumar, Prawin; Mukherjee, Aparna; Randev, Shivani; Medigeshi, Guruprasad R; Jat, Kana Ram; Kapil, Arti; Lodha, Rakesh; Kabra, Sushil Kumar

In our cohort, we did not observe significant change in V T and t PTEF /t E in children at 3 years of age with ARI, with or without viral infection during infancy. Studies have reported conflicting results on the influence of ARI/ wheezing on t PTEF /t E . Clarke et al performed a prospective study in 94 infants using TBFVL, and partial expiratory flow-volume concluded that t PTEF /t E is not a very Open access sensitive index in detection of airway obstruction. 36 A plethysmography-based study by Zhang et al in 444 children from 1 to 36 months of age reported that t PTEF /t E was significantly lower in a wheezing group than in the control group. 11 LRTI episodes in our cohort did not show significant association with RTC and RVRTC indices; however, TEF 50 /PTEF was significantly increased in comparison to children who did not have documented ARI during infancy. Evidence in literature both support and refute this observation. A recent study from Cape Town, South Africa, did lung function at 6 weeks and 1 year of age in 648 children and observed that repeated LRTI episodes were independently associated with decreased V T , increased respiratory rate and increased lung clearance index. 12 A study by Strope et al in 159 children (6-18 years of age) with history of LRTI during preschool age observed that boys with a history of wheezy LRTI had lower FEV 1.0 and FEV 1.0 /FVC; however, children without wheezy LRTI did not show any significant impact in PFT indices. 28 Strengths of the study It was a well-designed, prospective birth cohort study with minimal dropout rates and regular follow-up, including almost all respiratory tract infections during infancy. Effort was made to identify the aetiology of all ARIs in infancy, including virus, chlamydia, mycoplasma and other bacteria. Hence, we could also explore the association of infection with viruses like HMPV and HCoV and IPFT indices at a later stage. Instead of focusing only on LRTI, we have included all ARIs of infancy, majority of which were URIs. State-of-the-art IPFTs were performed by trained personnel in keeping with the standard requirements, thus generating robust, reliable data regarding lung functions.