“…Our prior analysis in the Sleep and Asthma Cohort (SAC) study, an unselected cohort of children with SCA (defined here as HbSS or HbSβ0 thalassemia), demonstrated that age was the only predictor of FEV 1 % predicted, with a decline of 0.3% for every additional year of age (−0.30; 95% CI, −0.56 to −0.05; P = 0.020) 5. Sex, asthma history, hemoglobin level, reticulocyte count, white blood cell count, incidence rate of severe acute pain requiring hospitalization, incidence rate of % predicted; (b) the strength of the association decreases as BMI percentile increases; and (c) at high values of BMI percentile, the association reverses and becomes negative, and FEV 1 % predicted declines because in the general pediatric population, with increasing total body fat percent, a negative slope is expected with decreasing FEV 1 % predicted values, after for adjusting age and sex.…”