Growth of lung function in children with sickle cell anemia

Lung disease is a common cause of morbidity among children with sickle cell disease (SCD). Although cross-sectional studies of children with SCD describe abnormal pulmonary function, the pattern of lung function growth in these children compared to children in the general population is not known. To provide preliminary evidence that growth of lung function is attenuated in children with SCD, we conducted a retrospective cohort study of children with hemoglobin SS (HbSS) ages 6-19 years who received at least two spirometry assessments for clinical care. The growth of lung function in these cases was compared to age, gender, and race-specific children without SCD or respiratory complaints from the Harvard Six Cities Study (H6CS). Seventy-nine children with HbSS contributed 363 spirometry measurements (mean per child = 4.6, median = 4.0, range = 2-17) and 255 controls contributed 1,543 spirometry measurements (mean per child = 6.1, median = 6.0, range = 2-13). Longitudinal forced expiratory volume in 1 sec (FEV(1)) was lower for boys and girls with HbSS compared to children in the general population, P = 0.031 and P = 0.002, respectively. When compared to the H6CS cohort, girls with HbSS showed lower longitudinal forced vital capacity (FVC) (P < 0.001) and FEV(1)/FVC (0.038); there was no difference in FVC or FEV(1)/FVC between boys in the HbSS and H6CS cohort. We conclude that growth of lung function is reduced in children with HbSS compared to children in the general population. Gender may influence the risk of developing abnormal lung function and airway obstruction in children with HbSS.