Results:
Case subjects: During the study period, 51 C-SCD performed a total of 115 DLCO measurements (mean of 2.25 DLCO measurements/subject; range: 1-6). The cohort of C-SCD was comprised of 41 African-American and 10 Hispanic children, with 29 and 22 of them being male and female, respectively. HbSS (41/51) was the most common genotype, followed by HbSC (8/51), Hb S/beta-thalassemia (1/51), and Hb-Lepore (1/51) (Table 1) . Mean(SD) DLCO was 87.9(17.2)%; there were no differences in DLCO between hemoglobin genotypes (HbSS vs. HbSC; p=0.74) or the two racial/ethnic groups (African American vs. Hispanic; p=0.82). The mean(SD) age and height of the study participants were 13.0(3.7) years and 150.1(17.6) cm, respectively at the time of PFTs. 91%, 50%, and 17% of C-SCD were on hydroxyurea, ICS, and LABA, respectively, around the time of PFTs. The average number of lifetime ACS episodes and VOC was 3.16 (2.63). Results for SCD biomarkers are summarized in