Anthropometric and spirometry z-scores in patients aged 6–18 years with sickle cell anaemia (SCA) from the UK and Nigeria (NIG)
| SCA UK | SCA NIG | Mean difference UK−NIG (95% CI; p value) | Controls NIG | |
| N (% male) | 101 (51%) | 154 (54%) | 364 (52%) | |
| Age, years | 11.7 (2.7) | 11.4 (3.2) | 0.3 (−0.5 to 1.0; 0.12) | 10.4 (2.4) |
| zHeight | 0.23 (1.25) | −1.77 (1.21) | 2.00 (1.68 to 2.30; <0.001) | −0.75 (1.51) |
| zBMI | 0.12 (1.23) | −1.49 (1.08) | 1.61 (1.32 to 1.90; <0.001) | −0.62 (1.32) |
| zFEV1 | −0.97 (1.06) | −1.38 (0.96) | 0.41 (0.15 to 0.66; 0.01) | −0.35 (0.99) |
| FEV1% | 87.1 (14.2) | 81.9 (13.3) | 5.1 (1.7 to 8.6; 0.003) | 95.2 (13.0) |
| zFVC | −0.68 (1.06) | −1.21 (0.96) | 0.53 (0.28 to 0.78; <0.001) | −0.31 (0.97) |
| FVC% | 91.1 (13.5) | 84.3 (12.7) | 6.8 (3.3 to 9.8; <0.001) | 95.9 (12.4) |
| zFEV1/FVC | −0.68 (0.97) | −0.47 (0.83) | −0.20 (−0.42 to 0.02; 0.07) | −0.08 (0.88) |
Results are presented as mean (SD), unless otherwise specified.
zBMI and zHeight values are based on WHO growth charts.25
Spirometry z-scores and % predicted are based on Global Lung Function Initiative 2012 equations for African–Americans.26
FEV1%, % predicted; FVC%, % predicted; zBMI, z-score body mass index; zFEV1, z-score FEV1; zFEV1/FVC, z-score FEV1/FVC; zFVC, z-score FVC; zHeight, z-score height.