Introduction
Patients and methods
Study design and population
Case definition
Data sources
Statistical analysis
Ethics
Reporting guidelines
Results
Incidence
Year | Incident cases | Person- years | Incidence rate (95% CI) |
---|---|---|---|
1994 | 32 | 1,304,220 | 24.5 (17.4–34.7) |
1995 | 36 | 1,406,927 | 25.6 (18.5–35.5) |
1996 | 31 | 1,596,103 | 19.4 (13.7–27.6) |
1997 | 30 | 1,884,001 | 15.9 (11.1–22.8) |
1998 | 24 | 2,123,764 | 11.3 (7.6–16.9) |
1999 | 47 | 2,576,123 | 18.2 (13.7–24.3) |
2000 | 47 | 3,150,278 | 14.9 (11.2–19.9) |
2001 | 58 | 3,459,183 | 16.8 (13.0–21.7) |
2002 | 81 | 3,815,730 | 21.2 (17.1–26.4) |
2003 | 79 | 4,039,225 | 19.6 (15.7–24.4) |
2004 | 76 | 4,236,700 | 17.9 (14.3–22.5) |
2005 | 92 | 4,352,147 | 21.1 (17.2–25.9) |
2006 | 86 | 4,396,878 | 19.6 (15.8–24.2) |
2007 | 94 | 4,434,807 | 21.2 (17.3–25.9) |
2008 | 77 | 4,441,042 | 17.3 (13.9–21.7) |
2009 | 82 | 4,451,968 | 18.4 (14.8–22.9) |
2010 | 82 | 4,386,173 | 18.7 (15.1–23.2) |
2011 | 103 | 4,285,455 | 24.0 (19.8–29.2) |
2012 | 96 | 4,210,630 | 22.8 (18.7–27.8) |
2013 | 74 | 3,978,397 | 18.6 (14.8–23.4) |
Cases | Person-years | Crude incidence rate (95% CI) | Crude rate ratios (95% CI) | Adjusted rate ratios (95% CI) | P valuea | |
---|---|---|---|---|---|---|
Overall | 1327 | 68,529,194 | 19.4 (18.3–20.4) | |||
Sex | ||||||
Male | 223 | 34,069,626 | 6.5 (5.7–7.5) | 1 | 1 | < 0.0001 |
Female | 1104 | 34,459,569 | 32.0 (30.2–34.0) | 4.9 (4.2–5.7) | 4.7 (4.1–5.4) | |
Age group (years) | ||||||
Age 0–15 | 35 | 11,955,198 | 2.9 (2.1–4.1) | 0.5 (0.3–0.7) | 0.5 (0.3–0.7) | Ptrend < 0.0001 |
Age 16–39 | 132 | 20,729,227 | 6.4 (5.4–7.6) | 1 | 1 | |
Age 40–54 | 338 | 15,329,346 | 22.0 (19.8–24.5) | 3.5 (2.8–4.2) | 3.4 (2.8–4.2) | |
Age 55–69 | 513 | 11,887,368 | 43.2 (39.6–47.1) | 6.7 (5.6–8.2) | 6.7 (5.5–8.1) | |
Age 70–84 | 283 | 7,100,416 | 39.9 (35.3–44.8) | 6.3 (5.1–7.7) | 5.7 (4.6–7.0) | |
Age 85+ | 26 | 1,528,196 | 17.0 (11.6–25.0) | 2.7 (1.8–4.1) | 2.1 (1.4–3.1) | |
Each additional calendar year | 1.0 (1.0–1.0) | Ptrend 0.24 | ||||
IMD 2010 | ||||||
Quintile 1—most deprived | 196 | 9,911,807 | 19.8 (17.2–22.7) | 1 | 1 | Ptrend = 0.63 |
Quintile 2 | 187 | 9,728,120 | 19.2 (16.7–22.2) | 1.0 (0.8–1.2) | 0.9 (0.8–1.2) | |
Quintile 3 | 157 | 8,356,976 | 18.8 (16.1–22.0) | 1.0 (0.8–1.2) | 1.0 (0.8–1.2) | |
Quintile 4 | 152 | 7,802,398 | 19.5 (16.6–22.8) | 1.0 (0.8–1.2) | 1.1 (0.9–1.3) | |
Quintile 5—least deprived | 120 | 6,304,656 | 19.0 (15.9–22.7) | 1.0 (0.8–1.2) | 1.1 (0.9–1.4) | |
IMD not known | 515 | 26,425,793 | 19.5 (17.9–21.2) | 1.0 (0.8–1.2) | 1.0 (0.9–1.2) |
Temporal trend
Age, sex, socioeconomic status
Prevalence
Cases | Denominator | Crude prevalence | Crude odds ratios (95% CI) | Adjusted Odds ratios (95% CI) | P value1 | |
---|---|---|---|---|---|---|
Overall | 1337 | 4,362,809 | 307 (290–323) | |||
Sex | ||||||
Male | 227 | 2,155,960 | 105 (92–120) | 1 | 1 | P < 0.0001 |
Female | 1110 | 2,206,814 | 503 (474–533) | 4.8 (4.1–5.5) | 4.6 (3.9–5.2) | |
Age group (years) | ||||||
Age 0–15 | 13 | 781,568 | 17 (9–28) | 0.2 (0.1–0.4) | 0.2 (0.1–0.4) | Ptrend < 0.0001 |
Age 16–39 | 111 | 1,322,291 | 84 (69–101) | 1 | 1 | |
Age 40–54 | 283 | 959,587 | 295 (262–331) | 3.5 (2.8–4.4) | 3.5 (2.8–4.4) | |
Age 55–69 | 505 | 754,643 | 669 (612–730) | 8.0 (6.5–9.8) | 7.9 (6.5–9.8) | |
Age 70–84 | 362 | 433,661 | 835 (751–925) | 10.0 (8.0–12.3) | 9.4 (7.6–11.7) | |
Age 85+ | 63 | 111,059 | 567 (436–726) | 6.8 (5.0–9.2) | 5.6 (4.1–7.7) | |
IMD 2010 | ||||||
Quintile 1 | 188 | 600,110 | 313 (270–361) | 1 | 1 | Ptrend = 0.68 |
Quintile 2 | 188 | 598,616 | 314 (271–362) | 1.0 (0.8–1.2) | 1.0 (0.8–1.2) | |
Quintile 3 | 147 | 519,240 | 283 (239–333) | 0.9 (0.7–1.1) | 0.9 (0.8–1.2) | |
Quintile 4 | 145 | 520,410 | 279 (235–328) | 0.9 (0.7–1.1) | 1.0 (0.8–1.3) | |
Quintile 5 | 110 | 424,476 | 259 (213–312) | 0.8 (0.7–1.0) | 1.1 (0.8–1.3) | |
IMD not known | 559 | 1,699,957 | 329 (302–357) | 1.0 (0.9–1.2) | 1.1 (0.9–1.3) |
Survival
Cases | Deaths | Years at risk | Crude mortality | Crude hazard ratios (95% CI) | Adjusted hazard ratios (95% CI) | P valuea | |
---|---|---|---|---|---|---|---|
Overall | 1327 | 302 | 6929 | 43.6 (38.9–48.8) | |||
Sex | |||||||
Male | 223 | 53 | 1119 | 47.4 (36.2–62.0) | 1 | 1 | P = 0.06 |
Female | 1104 | 249 | 5810 | 42.9 (37.9–48.5) | 0.9 (0.7–1.2) | 0.7 (0.5–1.0) | |
Age group (years) | |||||||
Age 0–15 | 35 | 1 | 136 | 7.4 (1.0–52.2) | 1.2 (0.1–11.9) | 1.2 (0.1–11.4) | Ptrend < 0.0001 |
Age 16–39 | 146 | 3 | 501 | 6.0 (1.9–18.6) | 1 | 1 | |
Age 40–54 | 390 | 20 | 1572 | 12.7 (8.2–19.7) | 2.2 (0.6–7.3) | 1.2 (0.7–7.6) | |
Age 55–69 | 668 | 89 | 2923 | 30.4 (24.7–37.5) | 5.4 (1.7–17.0) | 5.7 (1.8–17.9) | |
Age 70–84 | 473 | 152 | 1616 | 94.1 (80.3–110.3) | 16.7 (5.3–52.3) | 17.7 (5.6–55.7) | |
Age 85+ | 75 | 37 | 182 | 203.7 (147.6–281.2) | 36.2 (11.1–117.8) | 37.8 (11.6–123.2) | |
IMD 2010b | |||||||
Quintile 1 | 196 | 45 | 1048 | 42.9 (32.1–57.5) | 1 | 1 | Ptrend = 0.49 |
Quintile 2 | 187 | 42 | 999 | 42.1 (31.1–56.9) | 1.0 (0.6–1.5) | 1.0 (0.7–1.6) | |
Quintile 3 | 157 | 36 | 702 | 51.3 (37.0–71.1) | 1.2 (0.8–1.8) | 1.0 (0.6–1.5) | |
Quintile 4 | 152 | 37 | 795 | 46.6 (33.7–64.3) | 1.1 (0.7–1.7) | 1.0 (0.7–1.6) | |
Quintile 5 | 120 | 37 | 628 | 58.9 (42.7–81.3) | 1.3 (0.9–2.1) | 1.2 (0.8–1.9) | |
IMD not known | 515 | 105 | 2758 | 38.1 (31.4–46.1) | 0.9 (0.6–1.3) | 0.9 (0.6–1.2) |