Table 1 Responders to invitation letter by age, gender and Index of Multiple Deprivation (IMD)
|  | All invitees N = 10,927 | Responders to invitation N = 4572 |  | |
|---|---|---|---|---|
| Â | Number (%) | Number | Standardised percentage response a (95% CI) | Ratio of response rates (95% CI) |
Age | ||||
 45-54 years | 5229 (47.8) | 1698 | 33.4 (32.1, 34.7) | 0.57 (0.54,0.60) |
 55-64 years | 3367 (30.8) | 1535 | 46.2 (44.5, 47.9) | 0.79 (0.76,0.84) |
 65-75 years | 2331 (21.3) | 1339 | 57.8 (55.8, 59.8) | 1.0 |
Gender | ||||
 Female | 5604 (51.3) | 2638 | 46.7 (45.4, 48.0) | 1.0 |
 Male | 5323 (48.7) | 1934 | 36.8 (35.5, 38.1) | 0.80 (0.76,0.84) |
IMD national quintile b | ||||
 1 Most deprived | 712 (6.8) | 207 | 29.5 (26.2, 32.8) | 0.55 (0.50,0.61) |
 2 | 2768 (26.4) | 995 | 36.1 (34.4, 37.9) | 0.67 (0.63,0.72) |
 3 | 2960 (28.2) | 1242 | 41.2 (39.8, 43.2) | 0.77 (0.73,0.82) |
 4 | 2328 (22.2) | 1060 | 45.6 (43.6, 47.5) | 0.85 (0.80,0.90) |
 5 Least deprived | 1711 (16.3) | 914 | 53.4 (51.4, 56.0) | 1.0 |