Table 2.
Sociodemographic information and descriptive statistics for main exposures and outcomes in the original sample and subsamples
| Whole sample (n=14 684) | Individuals with data on FVC at 8, FSIQ at age 8 (n=6644) | Individuals with data on FVC and FSIQ at age 8 and complete covariates (n=4346) | Individuals with data on FVC at age 8, FSIQ at age 15 (n=4234) | Individuals with data on FVC at age 8, FSIQ at age 15 and complete covariates (n=2861) | |
| Sex—% male | 51.0 | 50.0 | 50.6 | 48.0 | 48.4 |
| Ethnic group— % white |
95.0 | 96.2 | 96.4 | 96.4 | 96.4 |
| Housing tenure—% owned | 73.3 | 83.3 | 86.8 | 85.8 | 88.9 |
| Maternal education— % > ‘O’ level |
35.4 | 43.9 | 42.7 | 48.8 | 47.7 |
| FEV1 % predicted—mean (SD) | NA | 99.4 (12.0) | 99.5 (11.9) | 99.4 (12.0) | 99.4 (12.0) |
| FVC % predicted—mean (SD) | NA | 99.2 (12.4) | 99.1 (12.3) | 99.1 (12.4) | 99.0 (12.4) |
| FSIQ in clinic—mean (SD) | NA | 104.3 (16.4) | 104.5 (16.2) | 95.1 (13.0) | 94.7 (12.9) |
All values to 1 decimal place.
FEV1, forced expiratory volume in one second; FSIQ, full-scale IQ; FVC, forced vital capacity; NA, not applicable.