Variable | Model 1: full study population (N=2940) | Model 2: BC (N=519) | Model 3: WBI (N=1052) | |||||||||||||||
Outcome statistics | Outcome statistics | Outcome statistics | ||||||||||||||||
(STI diagnosis in follow-up period) | (STI diagnosis in follow-up period) | (STI diagnosis in follow-up period) | ||||||||||||||||
Diagnoses (n) | Person-years | Incidence rate (%) | Univariable | Multivariable | Univariable | Multivariable | Univariable | Multivariable | ||||||||||
HR | P value | aHR | SE | P value | HR | P value | aHR | SE | P value | HR | P value | aHR | SE | P value | ||||
Demographic | ||||||||||||||||||
Age (years)* | ||||||||||||||||||
25+ (max. 80) | 119 | 2503 | 4.8 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
15–24 | 121 | 1686 | 7.2 | 0.96 | <0.01 | 0.98 | 0.01 | 0.04 | 0.96 | 0.01 | 0.96 | 0.02 | 0.04 | 1.34 | 0.31 | 0.96 | 0.02 | 0.10 |
Gender | ||||||||||||||||||
Male | 92 | 1372 | 6.7 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
Female | 148 | 2816 | 5.3 | 0.79 | 0.07 | 0.89 | 0.13 | 0.42 | 0.65 | 0.07 | 0.68 | 0.20 | 0.18 | 0.61 | 0.08 | 0.60 | 0.20 | 0.13 |
IMD | ||||||||||||||||||
Three least deprived quintiles | 44 | 1274 | 3.5 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
Two most deprived quintiles | 196 | 2898 | 6.8 | 1.95 | <0.01 | 1.46 | 0.25 | 0.03 | 0.69 | 0.12 | 0.50 | 0.14 | 0.01 | 2.63 | 0.01 | 2.32 | 0.84 | 0.02 |
Ethnic group | ||||||||||||||||||
WBI | 49 | 1500 | 3.2 | – | – | – | – | – | ||||||||||
White other | 23 | 551 | 4.2 | 1.31 | 0.29 | 1.40 | 0.36 | 0.18 | ||||||||||
Black African | 29 | 462 | 6.3 | 1.95 | <0.01 | 1.67 | 0.41 | 0.04 | ||||||||||
BC | 79 | 651 | 12.1 | 3.74 | <0.01 | 2.60 | 0.50 | <0.01 | ||||||||||
Black other | 6 | 49 | 12.4 | 3.81 | <0.01 | 3.57 | 1.57 | <0.01 | ||||||||||
Mixed/other | 38 | 526 | 7.2 | 2.23 | <0.01 | 1.69 | 0.38 | 0.02 | ||||||||||
Asian | 16 | 417 | 3.8 | 1.20 | 0.53 | 1.34 | 0.39 | 0.32 | ||||||||||
Degree-level education | ||||||||||||||||||
No | 160 | 2095 | 7.6 | – | – | – | – | – | – | – | – | – | – | – | – | |||
Yes | 79 | 2055 | 3.8 | 0.51 | <0.01 | 0.74 | 0.11 | 0.04 | 0.97 | 0.91 | 0.45 | 0.01 | 0.54 | 0.17 | 0.05 | |||
Currently employed | ||||||||||||||||||
No | 76 | 1130 | 6.7 | – | – | – | – | – | – | |||||||||
Yes | 164 | 3031 | 5.4 | 0.81 | 0.12 | 0.65 | 0.07 | 0.90 | 0.76 | |||||||||
Behavioural and attitudinal | ||||||||||||||||||
Contraception use in p12m (self or partner) | ||||||||||||||||||
Any barrier method | 143 | 2561 | 5.6 | – | – | – | – | – | – | |||||||||
Permanent/LARC/hormonal (without barrier) | 40 | 630 | 6.3 | 0.95 | 0.74 | 0.67 | 0.15 | 0.75 | 0.47 | |||||||||
Emergency/natural/no method only | 48 | 909 | 5.3 | 1.14 | 0.48 | 0.56 | 0.09 | 1.50 | 0.30 | |||||||||
Early sexual debut (<16 years of age) | ||||||||||||||||||
No | 112 | 2396 | 4.7 | – | – | – | – | – | – | – | – | – | ||||||
Yes | 128 | 1793 | 7.1 | 1.52 | <0.01 | 1.13 | 0.16 | 0.40 | 1.34 | 0.20 | 1.73 | 0.06 | ||||||
Self-perceived risk | ||||||||||||||||||
Don't think I'm at risk of getting any STI | 133 | 1893 | 7.0 | – | – | – | – | – | – | |||||||||
Think I'm at risk of STIs | 72 | 1647 | 4.4 | 0.63 | <0.01 | 0.69 | 0.143 | 0.69 | 0.28 | |||||||||
Attitudes to concurrency | ||||||||||||||||||
Negative attitude | 181 | 3600 | 5.0 | – | – | – | – | – | – | – | – | – | – | – | – | |||
Positive attitude | 38 | 355 | 10.7 | 2.12 | <0.01 | 1.94 | 0.04 | 1.25 | 0.45 | 0.54 | 3.06 | <0.01 | 2.06 | 0.81 | 0.07 | |||
Number of partners in p12m | ||||||||||||||||||
1 | 56 | 1559 | 3.6 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
2–4 | 95 | 1730 | 5.5 | 1.52 | 0.01 | 1.27 | 0.23 | 0.18 | 1.92 | 0.03 | 1.43 | 0.49 | 0.29 | 2.53 | 0.03 | 2.71 | 1.35 | 0.05 |
5 or more | 84 | 836 | 10.1 | 2.77 | <0.01 | 1.97 | 0.40 | <0.01 | 3.23 | <0.01 | 1.78 | 0.75 | 0.17 | 4.21 | <0.01 | 2.46 | 1.32 | 0.09 |
Number of new partners in p12m | ||||||||||||||||||
None | 51 | 1264 | 4.0 | – | – | – | – | – | – | |||||||||
1 | 60 | 1079 | 5.6 | 1.37 | 0.10 | 1.53 | 0.16 | 1.50 | 0.42 | |||||||||
2–4 | 72 | 1203 | 6.0 | 1.48 | 0.03 | 1.49 | 0.20 | 1.70 | 0.25 | |||||||||
5 or more | 49 | 547 | 9.0 | 2.20 | <0.01 | 3.24 | <0.01 | 4.01 | <0.01 | |||||||||
Partner concurrency in p12m | ||||||||||||||||||
No | 124 | 2805 | 4.4 | – | – | – | – | – | – | |||||||||
Yes | 95 | 1166 | 8.2 | 1.83 | <0.01 | 1.78 | 0.01 | 1.99 | 0.02 | |||||||||
Age mixing with any of most recent three partners | ||||||||||||||||||
No | 133 | 2346 | 5.7 | – | – | – | – | – | – | – | – | – | ||||||
Yes | 81 | 1341 | 6.0 | 1.06 | 0.66 | 0.61 | 0.07 | 1.73 | 0.06 | 2.37 | 0.78 | 0.01 | ||||||
Ethnic mixing with any of most recent three partners | ||||||||||||||||||
No | 81 | 1800 | 4.5 | – | – | – | – | |||||||||||
Yes | 136 | 1923 | 7.1 | 1.56 | <0.01 | 1.20 | 0.45 | 1.54 | 0.16 | |||||||||
Current partnership type | ||||||||||||||||||
Married/committed only | 80 | 1952 | 4.1 | – | – | – | – | – | – | – | – | – | – | – | – | |||
Casual only | 97 | 1309 | 7.4 | 1.80 | <0.01 | 1.29 | 0.22 | 0.13 | 2.15 | <0.01 | 1.44 | 0.44 | 0.23 | 1.98 | 0.05 | |||
Both | 14 | 132 | 10.6 | 2.55 | 0.01 | 1.65 | 0.50 | 0.10 | 1.88 | 0.25 | 1.14 | 0.65 | 0.81 | 2.69 | 0.19 | |||
Don't have partner | 46 | 751 | 6.1 | 1.49 | 0.03 | 1.30 | 0.25 | 0.17 | 1.10 | 0.81 | 0.65 | 0.29 | 0.33 | 1.98 | 0.08 | |||
Clinical† | ||||||||||||||||||
Time since last STI diagnosis | ||||||||||||||||||
Never | 117 | 3359 | 3.5% | – | – | – | – | – | – | |||||||||
At survey attendance | 91 | 590 | 15.4 | 4.34 | <0.01 | 4.04 | <0.01 | 3.54 | <0.01 | |||||||||
Within the 6 months before survey | 16 | 141 | 11.4 | 3.23 | <0.01 | 2.11 | 0.09 | 2.23 | 0.03 | |||||||||
Within the 7–12 months before survey | 16 | 99 | 16.2 | 4.57 | <0.01 | 2.78 | 0.02 | 4.35 | 0.02 | |||||||||
Type of STI diagnosed at survey and p12m | ||||||||||||||||||
None | 117 | 3359 | 3.5 | – | – | – | – | – | – | |||||||||
CT only | 36 | 388 | 9.3 | 2.64 | <0.01 | 2.16 | 0.02 | 1.79 | 0.23 | |||||||||
Any other STI (including or excluding CT) | 87 | 442 | 19.7 | 5.52 | <0.01 | 4.34 | <0.01 | 4.94 | <0.01 | |||||||||
Number of STI episodes at survey and p12m | ||||||||||||||||||
None | 117 | 3359 | 3.5 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
At survey only | 62 | 506 | 12.3 | 3.47 | <0.01 | 2.68 | 0.44 | <0.01 | 3.05 | <0.01 | 2.65 | 0.80 | <0.01 | 2.34 | 0.03 | 1.65 | 0.65 | 0.21 |
1 previous episode (±1 at survey) | 48 | 296 | 16.2 | 4.57 | <0.01 | 3.21 | 0.58 | <0.01 | 3.47 | <0.01 | 2.64 | 0.88 | <0.01 | 4.26 | <0.01 | 3.34 | 1.38 | <0.01 |
≥2 previous episodes (±1 at survey) | 13 | 28 | 46.6 | 12.53 | <0.01 | 6.85 | 2.10 | <0.01 | 5.54 | <0.01 | 5.81 | 2.73 | <0.01 | 28.00 | <0.01 | 29.94 | 23.92 | <0.01 |
Missing data full population: see table 1 footnote.
Missing data BC: degree-level education (5), current employment (1), contraception use (14), self-perceived risk (76), attitudes to concurrency (27), number of partners in p12m (11), number of new partners in p12m (14), partner concurrency in p12m (28), age mixing (66), ethnic mixing (62) and current partnership type (5).
Missing data WBI: IMD (7), degree-level education (6), current employment (4), contraception use (15), self-perceived risk (142), attitudes to concurrency (43), number of partners in p12m (10), number of new partners in p12m (15), partner concurrency in p12m (35), age mixing (104), ethnic mixing (95) and current partnership type (9).
Bold values indicate statistical significance.
*Age modelled as continuous.
†The time frame for clinical data was the survey attendance (±6 weeks) and the p12m.
aHR, adjusted HR; BC, black Caribbean; IMD, Index of Multiple Deprivation; LARC, long-acting reversible contraception; p12m, previous 12 months; SE, Standard error; WBI, white British/Irish.