Lung function and clinical risk factors for asthma in infants and young children with recurrent wheeze

Background: Although several risk factors for asthma have been identified in infants and young children with recurrent wheeze, the relevance of assessing lung function in this group remains unclear. We assessed whether lung function was reduced during the first 2 years in recurrently wheezy children, with and without clinical risk factors for developing subsequent asthma (i.e., parental asthma, personal history of rhinitis, wheezing without colds and/or eosinophil level >4%), when compared with healthy controls. Methods: Forced expiratory flows and volumes in steroid naive young children with ≥ 3 episodes of physician-confirmed wheeze and healthy controls, aged 8-20 months, were measured using the tidal and raised-volume rapid thoraco-abdominal compression manoeuvres. Results: Technically acceptable results were obtained in 50 wheezy children and 30 controls using tidal RTC, and 44 wheezy children and 29 controls with the raised-volume technique. After adjustment for sex, age, body length at test and maternal smoking, significant reductions in Z-scores for FEV0.5 (mean difference [95% CI]: -1.0 [-1.5; -0.5]), FEF75 (-0.6 [-1.0; -0.2]) and FEF25-75(-0.8 [-1.2; -0.4]) were observed in those with recurrent wheeze when compared with controls. Wheezy children with risk factors for asthma (n=15) had significantly lower Z-scores for FVC (-0.7 [-1.4; -0.04]) and FEF25-75 (-0.6 [-1.2; -0.1]) than those without such risk factors (n=29). Conclusions: When compared to healthy controls, airway function is reduced in young children with recurrent wheeze, particularly those at risk for subsequent asthma. These findings provide further evidence for associations between clinical risk factors and impaired respiratory function in early life.