Incidence of HIV infection in individuals who initially tested HIV negative during the period 1988–2009 (including testing of stored sera back to 1980) and had at least one subsequent test in the same period (n=59 807)
| N (col%) | HIV positive (row%) | Person-years | Rate | 95% CI | RR | 95% CI | |
| All | 59 807 | 620 (1.04) | 168 746 | 3.7 | 3.4 to 4.0 | – | |
| (a) MSM | 8667 | 375 (4.3) | 24 455 | 15.3 | 13.8 to 17.0 | – | |
| Age at initial test (years); mean=31.5 | |||||||
| <25 | 3105 (35.8) | 138 (4.4) | 8841 | 15.6 | 13.1 to 18.4 | Ref. | |
| 25–34 | 2939 (33.9) | 148 (5.0) | 8731 | 17.0 | 14.3 to 19.9 | 1.04 | 0.83 to 1.32 |
| 35–44 | 1671 (19.3) | 72 (4.3) | 4668 | 15.4 | 12.1 to 19.4 | 0.93 | 0.70 to 1.24 |
| 45+ | 952 (11.0) | 17 (1.8) | 2217 | 7.7 | 4.5 to 12.3 | 0.48 | 0.29 to 0.79 |
| HIV risk exposure* | |||||||
| MSM only | 7017 (81.0) | 310 (4.4) | 18 063 | 17.2 | 15.3 to 19.2 | – | |
| MSM and heterosexual† | 1419 (16.4) | 53 (4.3) | 5069 | 10.5 | 7.8 to 13.7 | 0.66 | 0.49 to 0.88 |
| MSM and IDU† | 231 (2.7) | 12 (5.2) | 1452 | 8.3 | 4.3 to 14.4 | 0.52 | 0.29 to 0.93 |
| Calendar year period (time dependent)* | |||||||
| <1995 | 1471 (17.0) | 47 (3.2) | 3337 | 14.1 | 10.3 to 18.7 | Ref. | |
| 1995–1999 | 2270 (26.2) | 83 (3.7) | 5384 | 15.4 | 12.2 to 19.1 | 1.09 | 0.76 to 1.57 |
| 2000–2004 | 3589 (41.4) | 109 (3.0) | 6582 | 16.6 | 13.6 to 20.0 | 1.20 | 0.84 to 1.69 |
| 2005–2009 | 5325 (61.4) | 136 (2.6) | 9152 | 14.9 | 12.5 to 17.6 | 1.06 | 0.76 to 1.47 |
| Health board | |||||||
| Lothian | 2099 (24.2) | 96 (4.6) | 5957 | 16.1 | 13.1 to 19.7 | 1.19 | 0.92 to 1.54 |
| GG & C | 1930 (22.3) | 84 (4.4) | 4515 | 18.6 | 14.8 to 23.0 | 1.27 | 0.97 to 1.65 |
| Grampian | 649 (7.5) | 22 (3.4) | 1882 | 11.7 | 7.3 to 17.7 | 0.88 | 0.56 to 1.38 |
| Tayside | 326 (3.8) | 15 (4.6) | 1098 | 13.7 | 7.6 to 22.5 | 1.08 | 0.63 to 1.84 |
| Other | 3663 (42.3) | 158 (4.3) | 11 003 | 14.4 | 12.2 to 16.8 | Ref. | |
| (b) Heterosexual risk group | 39 671 (100) | 227 (0.6) | 107 881 | 2.1 | 1.8 to 2.4 | – | |
| Sex | |||||||
| Male | 21 037 (53.0) | 153 (0.7) | 61 130 | 2.5 | 2.1 to 2.9 | 0.98 | 0.72 to 1.32 |
| Female | 18 634 (47.0) | 74 (0.4) | 46 485 | 1.6 | 1.3 to 2.0 | Ref. | |
| Age at initial test (years), mean=31.4 | |||||||
| <25 | 19 719 (49.7) | 80 (0.4) | 55 119 | 1.5 | 1.2 to 1.8 | Ref. | |
| 25–34 | 12 612 (31.8) | 85 (0.7) | 35 525 | 2.4 | 1.9 to 3.0 | 1.56 | 1.15 to 2.13 |
| 35–44 | 4745 (12.0) | 46 (1.0) | 11562 | 4.0 | 3.0 to 5.3 | 2.55 | 1.76 to 3.69 |
| 45+ | 2595 (6.5) | 16 (0.6) | 5408 | 3.0 | 1.7 to 4.8 | 1.93 | 1.11 to 3.34 |
| HIV risk exposure* | |||||||
| Heterosexual only | 34 376 (86.7) | 117 (0.3) | 78 704 | 1.5 | 1.2 to 1.8 | – | |
| Heterosexual and MSM† | 1419 (3.6) | 53 (3.7) | 5069 | 10.5 | 7.8 to 13.7 | 6.08 | 4.32 to 8.54 |
| Heterosexual and IDU† | 2939 (7.4) | 51 (1.7) | 19 911 | 2.6 | 1.9 to 3.4 | 1.47 | 1.05 to 2.04 |
| Calendar year period (time-dependent)* | |||||||
| <1995 | 6596 (16.6) | 41 (0.6) | 14 358 | 2.9 | 2.0 to 3.9 | Ref. | |
| 1995–1999 | 9403 (23.7) | 59 (0.6) | 22 028 | 2.7 | 2.0 to 3.5 | 0.94 | 0.63 to 1.39 |
| 2000–2004 | 15 517 (39.1) | 65 (0.4) | 27 973 | 2.3 | 1.8 to 3.0 | 0.84 | 0.57 to 1.25 |
| 2005–2009 | 25 628 (64.6) | 62 (0.2) | 43 256 | 1.4 | 1.1 to 1.8 | 0.58 | 0.39 to 0.87 |
| Health board | |||||||
| Lothian | 10 519 (26.5) | 52 (0.5) | 29 745 | 1.8 | 1.3 to 2.3 | 0.85 | 0.61 to 1.20 |
| GG & C | 6419 (16.2) | 28 (0.4) | 14 022 | 2.0 | 1.3 to 2.9 | 0.88 | 0.58 to 1.34 |
| Grampian | 4967 (12.5) | 20 (0.4) | 13 743 | 1.5 | 0.9 to 2.2 | 0.68 | 0.42 to 1.10 |
| Tayside | 3049 (7.7) | 34 (1.1) | 9955 | 3.4 | 2.4 to 4.8 | 1.60 | 1.08 to 2.37 |
| Other | 14 717 (37.1) | 93 (0.6) | 40 148 | 2.3 | 1.9 to 2.8 | Ref. | |
| (c) IDUs | 8471 | 121 (1.4) | 45 688 | 2.7 | 2.2 to 3.2 | – | |
| Sex | |||||||
| Male | 6074 (71.7) | 83 (1.4) | 12 419 | 2.5 | 2.0 to 3.1 | 0.71 | 0.47 to 1.05 |
| Female | 2397 (28.3) | 38 (1.6) | 33 269 | 3.1 | 2.2 to 4.2 | Ref. | |
| Age at initial test (years), mean=31.3 | |||||||
| <25 | 4043 (47.7) | 60 (1.5) | 24 534 | 2.5 | 1.9 to 3.4 | Ref. | |
| 25–34 | 3493 (41.2) | 55 (1.6) | 17 429 | 3.2 | 2.4 to 4.1 | 1.40 | 0.96 to 2.03 |
| 35+ | 935 (11.0) | 6 (0.6) | 3726 | 1.6 | 0.6 to 3.5 | 0.71 | 0.31 to 1.64 |
| HIV risk exposure* | |||||||
| IDU only | 5130 (60.6) | 59 (1.2) | 23 429 | 2.5 | 1.9 to 3.2 | – | |
| IDU and heterosexual† | 2939 (34.7) | 51 (1.7) | 19 911 | 2.6 | 1.9 to 3.4 | 0.96 | 0.66 to 1.39 |
| IDU and MSM† | 231 (2.7) | 12 (5.2) | 1452 | 8.3 | 4.3 to 14.4 | 3.67 | 1.98 to 6.80 |
| Calendar year period (time-dependent)* | |||||||
| <1995 | 3043 (35.9) | 42 (1.4) | 8232 | 5.1 | 3.7 to 6.9 | Ref. | |
| 1995–1999 | 4552 (53.7) | 37 (0.8) | 12 968 | 2.9 | 2.0 to 3.9 | 0.56 | 0.36 to 0.87 |
| 2000–2004 | 5008 (59.1) | 26 (0.5) | 14 838 | 1.8 | 1.1 to 2.6 | 0.36 | 0.22 to 0.58 |
| 2005–2009 | 3945 (46.6) | 16 (0.4) | 9651 | 1.7 | 0.9 to 2.7 | 0.35 | 0.19 to 0.62 |
| Health board | |||||||
| Lothian | 1860 (22.0) | 25 (1.3) | 11 363 | 2.2 | 1.4 to 3.2 | 0.72 | 0.44 to 1.18 |
| GG & C | 1717 (20.3) | 23 (1.3) | 8080 | 2.9 | 1.8 to 4.3 | 0.87 | 0.52 to 1.45 |
| Grampian | 1217 (14.4) | 7 (0.6) | 6025 | 1.2 | 0.5 to 2.4 | 0.43 | 0.19 to 0.95 |
| Tayside | 906 (10.7) | 21 (2.3) | 5419 | 3.9 | 2.4 to 5.9 | 1.22 | 0.72 to 2.05 |
| All other | 2771 (32.7) | 45 (1.5) | 14 802 | 3.0 | 2.2 to 4.1 | Ref. | |
Results are stratified by the three main reported risk activities leading to infection (8667 with MSM, 39 671 with heterosexual and 8471 with IDU). Rate is per 1000 person-years of follow-up, where time of seroconversion for those with a positive test result is estimated as the midpoint between the dates of the last negative and first positive tests.
↵* Column percentages can sum to >100% because an individual can be counted in more than one category.
↵† The reference category for the RR is absence of the named additional risk. Three thousand and two individuals (of the total 59 807) with risk activities other than these three, or with no reported risk, are not separately presented.
Col%, column percentage; GG & C, Greater Glasgow & Clyde; IDU, injecting drug user; NA, not applicable; NHS, National Health Service; RR, adjusted rate ratio estimated using multifactorial Poisson regression.