Table 4

Independent risk factors for four common sexually transmitted infections in attenders at three GUM clinics in England, 1996: females

	Warts			HSV			Gonorrhoea			Chlamydia
Variable	Odds ratio	95% CI	p Value	Odds ratio	95% CI	p Value	Odds ratio	95% CI	p Value	Odds ratio	95% CI	p Value
*Number of partners in the past 3 months for MMC (see Methods for details).
Clinic
Sheffield	1.00			1.00			1.00			1.00
St Thomas's	0.90	0.73–1.12		1.22	0.90–1.66		1.72	1.14–2.59		0.44	0.35–0.55
MMC	0.61	0.50–0.74	<0.001	0.71	0.52–0.96	<0.005	0.33	0.19–0.58	<0.001	0.53	0.44–0.64	<0.001
Age group
13–15	2.20	0.91–5.33		1.11	0.26–4.73		18.98	5.99–60.09		30.73	15.48–61.00
16–19	3.07	2.24–4.22		1.30	0.83–2.05		14.75	6.69–32.55		15.28	9.65–24.19
20–24	2.27	1.70–3.03		1.27	0.87–1.86		4.47	2.01–9.92		8.15	5.19–12.78
25–34	1.41	1.05–1.88		1.13	0.79–1.63		1.95	0.87–4.40		4.69	2.99–7.36
35+	1.00		<0.001	1.00		0.72	1.00		<0.001	1.00		<0.001
Sexual orientation
Heterosexual	1.00			1.00			1.00			1.00
Homo/bisexual	0.54	0.24–1.24	0.11	0.44	0.11–1.80	0.19	0.58	0.08–4.29	0.56	0.08	0.01–0.55	<0.001
Ethnic group
White	1.00			1.00			1.00			1.00
Black Caribbean	0.30	0.21–0.45		0.59	0.38–0.91		3.13	2.06–4.76		2.08	1.62–2.68
Black African	0.45	0.27–0.77		0.48	0.23–1.01		2.34	1.24–4.41		0.78	0.47–1.29
Asian	0.38	0.19–0.74		0.82	0.40–1.69		1.59	0.62–4.04		1.26	0.81–1.98
Other/mixed	0.70	0.51–0.96	<0.001	0.56	0.33–0.93	<0.01	3.23	1.82–5.74	<0.001	1.16	0.84–1.48	<0.001
Number of partners in past 12 months*
0–1	1.00			1.00			1.00			1.00
2	1.11	0.92–1.35		1.03	0.78–1.37		1.58	1.11–2.26		1.41	1.18–1.69
3+	1.26	1.02–1.54	0.09	1.13	0.83–1.55	0.75	1.82	1.22–2.71	<0.005	1.57	1.30–1.90	<0.001
Previous STI	0.62	0.51–0.75	<0.001	0.66	0.50–0.86	<0.005	0.93	0.66–1.30	0.18	0.89	0.76–1.06	0.18
Ever injected drugs	0.57	0.23–1.41	0.19	0.59	0.14–2.41	0.42		—	—	0.84	0.40–1.80	0.65