Table 3.

Factors associated with syphilis infection among 3717 Chinese MSM

Characteristic	No. of MSM syphilis positive (%)	Crude OR (95% CI)	P-value	AOR (95% CI)	P-value
Commercial sex
NC-MSM	302 (8.7)	Ref.	0.28	Ref.	0.262
MSM-buying	7 (6.8)	0.8 (0.4–1.7)		0.5 (0.2–1.4)
MSM-selling	18 (12.1)	1.4 (0.9–2.4)		1.5 (0.7–3.3)
HIV positive
No	249 (7.5)	Ref.	<0.001	Ref.	<0.001
Yes	78 (19.0)	2.9 (2.2–3.8)		2.0 (1.5–2.8)
HSV-2 positive
No	208 (7.0)	Ref.	<0.001	Ref.	<0.001
Yes	81 (19.8)	3.3 (2.5–4.4)		2.7 (2.0–3.7)
Age (per year)		1.0 (1.0–1.1)	0.001	1.0 (1.0–1.1)	0.002
Married to a woman
No	222 (7.9)	Ref.	<0.001	Ref.	0.45
Yes	105 (11.8)	1.6 (1.2–2.0)		0.9 (0.6–1.2)
Time living in the study city
>6 months	244 (8.7)	Ref.	0.31	_	_
≤6 months	18 (6.9)	0.8 (0.5–1.3)
Student
No	305 (9.6)	Ref.	<0.001	Ref.	0.170
Yes	22 (4)	0.4 (0.3–0.6)		0.7 (0.4–1.2)
Education
College or above	145 (6.8)	Ref.	<0.001	Ref.	0.080
High school or below	182 (11.5)	1.8 (1.4–2.2)		1.3 (1.0–1.7)
Seeking partners online
No	135 (11.7)	Ref.	<0.001	Ref.	0.082
Yes	190 (7.4)	0.6 (0.5–0.8)		0.8 (0.6–1.0)
Number of male sex partners in past 6 months
0–2	175 (7.6)	Ref.	0.002	Ref.	0.002
3–9	113 (10.7)	1.5 (1.1–1.9)		1.5 (1.1–1.9)
≥10	35 (11.9)	1.7 (1.1–2.4)		1.5 (1.0–2.5)
Drug use in past 6 months
No	182 (7.8)	Ref.	0.024	Ref.	0.007
Yes	91 (10.3)	1.4 (1.0–1.8)		1.5 (1.1–2.0)
UAI in past 6 months
No	102 (7.3)	Ref.	0.013	Ref.	0.038
Yes	225 (9.7)	1.4 (1.1–1.7)		1.3 (1.0–1.8)
Predominant position in anal sex
Receptive	265 (12.8)	Ref.	0.23	_	_
Insertive	139 (9.0)	0.9 (0.7–1.1)