Table 1

Characteristics of all linked participants with known asthma status compared to those with complete ALSPAC parent-reported data

GPRD-recorded characteristicsLinked participants who did not exit GPRD before age 9 (n=699)Participants with complete ALSPAC parent-reported data* (n=141)
Sex—male348 (50%)70 (50%)
IMD2 quintile—least deprived68 (13%)24 (24%)
Second155 (30%)30 (30%)
Third120 (24%)27 (27%)
Fourth58 (11%)8 (8%)
Most deprived109 (21%)11 (11%)
Asthma—cumulative incidence115 (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.