Characteristics of all linked participants with known asthma status compared to those with complete ALSPAC parent-reported data
| GPRD-recorded characteristics | Linked participants who did not exit GPRD before age 9 (n=699) | Participants with complete ALSPAC parent-reported data* (n=141) |
|---|---|---|
| Sex—male | 348 (50%) | 70 (50%) |
| IMD2 quintile—least deprived | 68 (13%) | 24 (24%) |
| Second | 155 (30%) | 30 (30%) |
| Third | 120 (24%) | 27 (27%) |
| Fourth | 58 (11%) | 8 (8%) |
| Most deprived | 109 (21%) | 11 (11%) |
| Asthma—cumulative incidence | 115 (16%) | 26 (18%) |
*The denominator for IMD is slightly lower (510 for all linked participants with GPRD asthma status at age 9; 100 for those with complete ALSPAC parent-reported data) as this variable is not complete within GPRD.
ALSPAC, Avon Longitudinal Study of Parents and Children; GPRD, General Practice Research Database; IMD, index of multiple deprivation.