Aims To prospectively undertake longitudinal assessment of lung function in children with sickle cell disease (SCD) and similar aged and ethnic matched controls. Our aim was to test the hypotheses that lung function in SCD children, but not controls would deteriorate with increasing age and the rate of decline would be greater in younger children who are more likely to have suffered acute chest syndrome (ACS) episodes.

Methods Two cohorts of SCD children and age and ethnic matched controls were recruited. Cohort one (47 SCD children and 26 controls) had a median age of 8.8 years at recruitment and were followed for two years. Cohort two (45 SCD children and 26 controls) were recruited at an older age (median age 10.2 years) than cohort one (p = 0.007) and were followed for ten years. Forced expiratory volume in one second (FEV₁), vital capacity (VC), forced expiratory flow between twenty-five and seventy-five% of VC (FEF _25–75), total lung capacity (TLC) and residual volume (RV) were measured at recruitment and at the end of follow-up.

Results In both groups of SCD children, but in neither control group, lung function declined significantly. The rate of decline was greater in cohort one than cohort two for FEV₁ (p = 0.008), VC (p = 0.001), FEF_25–75 (p = 0.030), TLC (p = 0.004), and RV (p = 0.043). During follow-up, ACS episodes were more common in cohort one than cohort two (one episode per 1.93 patient/years versus one episode per 12.6 patient/years) p < 0.0001. ACS episodes were the only independent predictor of a greater decline in lung volumes.

Conclusions Lung function deteriorated in SCD children compared to similar aged and ethnic matched controls. The most rapid period of deterioration took place during early childhood when ACS episodes were more common. Our results suggest that treatment strategies to prevent ACS episodes need to be started in young SCD children if they are to be most effective in preventing the decline in lung function.