Table 1 Distribution of Demographic and Socioeconomic Variables Among Included, Excluded and Potential Controls in a Case-Control Study of Campylobacter Enteritis, England 2005-6
From: Effect of reminders on mitigating participation bias in a case-control study
| Â | Group | 1 | 2 | 3 | 4 | 5 | Â | Â |
|---|---|---|---|---|---|---|---|---|
| Â | Â | Included controls | Excluded controls | Active refusers | Incorrect addresses | Passive refusers | All | % |
Sex | Female | 54.0% | 58.1% | 50.7% | 33.6% | 43.1% | 7,111 | 48.0% |
| Â | Male | 46.0% | 41.9% | 49.3% | 66.4% | 56.9% | 7,703 | 52.0% |
|  | Total § | 3,983 | 1,283 | 2,200 | 749 | 6,599 | 14,814 |  |
Age group | 18-24 | 8.9% | 6.8% | 7.2% | 21.8% | 16.9% | 1,728 | 11.9% |
| Â | 25-34 | 17.9% | 14.7% | 11.5% | 24.4% | 23.4% | 2,628 | 18.1% |
| Â | 35-44 | 19.6% | 18.8% | 14.8% | 21.7% | 22.6% | 2,992 | 20.6% |
| Â | 45-54 | 19.6% | 24.7% | 14.0% | 12.7% | 15.6% | 2,506 | 17.2% |
| Â | 55-64 | 14.3% | 17.1% | 15.1% | 8.7% | 10.1% | 2,009 | 13.8% |
| Â | 65+ | 19.6% | 17.8% | 37.4% | 10.8% | 11.3% | 2,673 | 18.4% |
|  | Total †| 3,983 | 1,181 | 2,144 | 743 | 6,485 | 14,536 |  |
IMD quintile | 1 (most deprived) | 16.5% | 15.4% | 19.3% | 26.4% | 27.3% | 3,267 | 22.2% |
| Â | 2 | 16.2% | 16.4% | 19.7% | 20.2% | 19.6% | 2,727 | 18.5% |
| Â | 3 | 19.9% | 19.3% | 18.4% | 19.2% | 18.7% | 2,808 | 19.0% |
| Â | 4 | 21.5% | 22.2% | 20.0% | 15.5% | 17.5% | 2,837 | 19.2% |
| Â | 5 | 25.8% | 26.7% | 22.6% | 18.7% | 16.9% | 3,106 | 21.1% |
|  | Total ‡ | 3,912 | 1,283 | 2,200 | 749 | 6,601 | 14,745 |  |