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

Earlier studies have mostly focused on LRTI and the influence of RSV or RV infection; association of increased airway resistance, asthma or recurrent wheezing episodes was observed in many of these studies. 4 10 13 14 A birth cohort study 'Childhood Origin of Asthma' from Wisconsin, USA, had shown that infection with RSV (OR=2.6), RV (OR=9.8) or both RV and RSV (OR=10) led to increased risk of development of asthma at 6 years of age. Another longitudinal study from Perth, Australia, 'The Childhood Asthma Study' observed that infection with RSV or RV in the first year of life was a risk factor for asthma at 5 years of age. 31 A review by Drysdale et al concluded that RSV LRTI during infancy leads to reduced lung function indices, namely FEV 1.0 , FEV/FVC, peak expiratory flow rate and increased residual volume and airway resistance on follow-up even in early adulthood. 32 Korppi et al in a prospective study of 20 years follow-up observed abnormal lung function (lower FEV% and MEF 50 ) in children with a history of RSV infection in infancy. 33 A study from Madrid, Spain, had observed that infection with HMPV during infancy was a strong risk factor for the development of asthma in 3-5 years of age (OR=15.9), followed by RSV bronchiolitis (OR=10.1). 34 In the present study, we observed that all viral ARIs, irrespective of the specific aetiology, influenced the IPFT indices at a later stage. Apart from RSV and RV, children with documented HMPV and HCoV infection during infancy also had lower FEV and flow rate indices at 3 years of age. A birth cohort study from Tucson, Arizona, had observed that infants (n=123) with poor airway function during early infancy (measured by Vʹ max, FRC ) had continued to have lower values for FEV 1.0 , FEF 25-75 and FEV 1.0 /FVC ratio at 22 years of age after adjusting for age, sex, weight and height. 5 In our cohort, baseline tidal volume measured in the neonatal period did not affect the IPFT indices at 3 years of age, as seen in the adjusted analysis.