| Birth year (for records with day of birth 13th and 28th of each month in these years) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1992 (n = 100,443) | 1998 (n = 120,470) | 2005 (n = 106,450) | 2012 (n = 89,896) | |||||||||
| Record characteristics | NHS number (%) | Postcode (%) | NHS number (%) | Postcode (%) | NHS number (%) | Postcode (%) | NHS number (%) | Postcode (%) | ||||
| Overall | n | 43.8 | 3.8 | n | 4.6 | 12.3 | n | 5.3 | 30.7 | n | 0.7 | 47.3 |
| Sex | ||||||||||||
| Missing | 138 | 15.9 | 1.4 | 166 | 66.3 | 16.9 | 27 | 55.6 | 33.3 | 19 | 10.5 | 57.9 |
| Male | 60,285 | 4.2 | 3.8 | 54,779 | 37.6 | 13.0 | 47,939 | 5.5 | 33.0 | 40,849 | 0.7 | 50.4 |
| Female | 40,020 | 7.7 | 3.9 | 65,525 | 35.6 | 11.7 | 58,484 | 4.9 | 28.7 | 49,028 | 0.7 | 44.7 |
| Ethnic group | ||||||||||||
| Missing | 18,988 | 11.3 | 3.9 | 48,098 | 53.5 | 16.9 | 19,938 | 8.5 | 47.5 | 7,966 | 2.1 | 40.6 |
| White | 70,455 | 3.7 | 4.0 | 59,977 | 24.0 | 9.3 | 67,887 | 4.2 | 26.1 | 62,037 | 0.5 | 47.6 |
| Mixed | 1,264 | 4.4 | 4.0 | 1,023 | 4.7 | 2.1 | 2,755 | 4.3 | 26.7 | 3,876 | 0.6 | 51.6 |
| Asian | 4,643 | 7.8 | 2.6 | 5,529 | 25.8 | 7.2 | 8,473 | 4.1 | 28.6 | 9,027 | 0.6 | 49.4 |
| Black | 3,103 | 6.9 | 2.2 | 2,909 | 33.2 | 6.6 | 4,665 | 6.4 | 32.0 | 3,963 | 1.2 | 50.0 |
| Chinese/Other | 1,990 | 14.2 | 2.7 | 2,934 | 49.6 | 16.1 | 2,732 | 7.4 | 29.3 | 3,027 | 1.6 | 44.1 |
| Socio-economic group | ||||||||||||
| Missing | 3,836 | 8.2 | 14,784 | 61.7 | 32,644 | 6.5 | 42,523 | 0.4 | ||||
| Low deprivation | 66,956 | 5.1 | 75,884 | 32.3 | 51,755 | 4.1 | 33,525 | 0.8 | ||||
| High deprivation | 28,921 | 5.3 | 29,438 | 34.3 | 21,613 | 4.6 | 13,601 | 0.9 | ||||
| Foreign | 620 | 57.6 | 341 | 80.6 | 324 | 78.7 | 214 | 43.5 | ||||
| No fixed abode | 110 | 21.8 | 23 | 39.1 | 114 | 14.0 | 33 | 0.0 | ||||
| Episode type | ||||||||||||
| Other episode | 83,356 | 17.1 | 2.8 | 66,454 | 4.5 | 2.7 | 45,200 | 1.1 | 2.5 | |||
| Birth episode | 37,114 | 80.1 | 32.1 | 39,996 | 6.3 | 77.0 | 44,696 | 0.3 | 92.6 | |||
Note. Missing data on postcode refer to missing after excluding invalid or communal postcodes, and postcodes denoting ‘no fixed abode’ or foreign patients. The ‘mixed’ ethnic group was not recorded until April 2001 but appears in the 1992 and 1998 cohorts if taken from episodes from 2001 onwards. Proportions of missing data for local patient ID within provider are very small (<0.1%) and not shown here. High deprivation is defined as the most deprived quintile of IMD2004