Table 1.

Prevalence and odds of C. trachomatis and N. gonorrhoeae infections by socio-demographic and behavioral characteristics and other STIs

Factor	Sample size	Gonorrhoea			Chlamydia
		%	OR (95% CI)		%	OR (95% CI)
FSW category
High-tier	1192	5.54	Reference	—	16.36	Reference	—
Middle-tier	1298	5.24	0.94 (0.67–1.34)	0.74	16.87	1.04 (0.84–1.28)	0.73
Low-tier	609	8.04	1.49 (1.02–2.19)	0.04	20.03	1.28 (1.00–1.65)	0.05
Age group (years)
15–20	617	8.10	Reference	—	27.88	Reference	—
21–25	1149	5.05	0.60 (0.41–0.89)	0.01	18.53	0.59 (0.47–0.74)	<0.001
26–30	648	4.94	0.59 (0.37–0.93)	0.02	10.03	0.29 (0.21–0.39)	<0.001
>30	685	6.28	0.76 (0.50–1.16)	0.20	12.55	0.37 (0.28–0.49)	<0.001
Geographic area
Other provinces	2301	5.43	Reference	—	16.30	Reference	—
Guangxi	798	7.27	1.36 (0.99–1.88)	0.06	20.18	1.30 (1.06–1.59)	0.01
Education level
Primary school or below	460	7.17	Reference	—	14.56	Reference	—
Secondary school	2074	5.59	0.77 (0.51–1.14)	0.19	17.84	1.27 (0.96–1.69)	0.09
High school or above	562	6.05	0.83 (0.51–1.37)	0.47	17.61	1.25 (0.89–1.76)	0.19
Marital status
Never married	1890	5.38	Reference	—	19.79	Reference	—
Married	1113	6.65	1.25 (0.92–1.70)	0.15	13.57	0.64 (0.52–0.78)	<0.001
Divorced	87	5.75	1.07 (0.42–2.70)	0.88	11.49	0.53 (0.27–1.03)	0.06
Consistent condom use in past month
Yes	1611	6.33	Reference	—	16.57	Reference	—
No	1488	5.44	0.85 (0.63–1.15)	0.29	17.08	1.11 (0.92–1.34)	0.27
Other STIs
Syphilis	200	9.00	1.64 (0.99–2.73)	0.06	14.00	0.77 (0.51–1.15)	0.20
Gonorrhoea	183	—	—	—	28.41	1.99 (1.43–2.79)	<0.001
Chlamydia	536	9.70	1.99 (1.43–2.79)	<0.001	—	—	—

OR: odds ratio; CI: confidence interval.