Comparison of surveys throughout the United Kingdom (Poser criteria)
| Devon 2001 | Cambridge (N Cambs) 1993 | Southampton 1987 | Sussex 1991 | Leeds 1996 | SE Wales 1985 | Tayside Scotland 1996 | Northern Ireland 1996 | |
|---|---|---|---|---|---|---|---|---|
| Values in brackets are 95% confidence intervals. | ||||||||
| Population | 341 796 | 378 959 | 411 000 | 596 394 | 732 061 | 376 718 | 395 600 | 151 000 |
| Number of cases | 446 | 449 | 411 | 665 | 712 | 441 | 727 | 288 |
| Crude prevalence (/100 000) | 131 (118 to 143) | 118 (108 to 130) | 99 (89 to 109) | 136 | 97 | 117 (106 to 128) | – | 191 (169 to 213) |
| Prevalence of definite and probable (/100 000) | 118 (106 to 129) | 107 (98 to 118) | 95 (88 to 107) | 111 (103 to 120) | 85 | 101 | 184 (171 to 198) | 168 (148 to 189) |
| Prevalence of clinically definite cases only (/100 000) | 89 | 75 | 76 | 89 | 44 | 79 | 114 | 123 |
| Mean age (years) | 52 | 50 | 48.6 | 48.6 | 51 | 48.7 | 49.5 | 49.3 |
| Mean age of onset (years) | 34.6 | 33.8 | 33 | 33.1 | 34 | 32 | – | 32 |
| Mean duration (years) | 17.3 | 16.5 | 15.7 | 15.5 | 16 | 16.5 | 15 | 18.4 |
| Sex ratio F:M | 2.65 | 2.2 | 2.1 | 2.5 | 2.8 | 2 | 2.8 | 2.1 |