Table 2. PRs and 95% CIs for commercial sex characteristics comparing low-fee and medium-fee FSW in three provinces in China, 2012.

	Total (N=1487) No. (%)	Low-fee FSW (N=417) No. (%)	Medium-fee FSW (N=1070) No. (%)	PR (95% CI)	p Value*	APR (95% CI)	p Valve
Age at first commercial sex (years)
14–19	324 (21.9)	63 (15.3)	261 (24.4)	1.0 (Ref)
20–21	338 (22.8)	78 (18.9)	260 (24.3)	1.2 (0.9 to 1.6)
22–24	378 (25.5)	119 (28.9)	259 (24.2)	1.6 (1.2 to 2.1)
25–29	266 (18.0)	74 (18.0)	192 (18.0)	1.4 (1.1 to 1.9)
30–51	174 (11.8)	78 (18.9)	96 (9.0)	2.3 (1.7 to 3.0)	<0.001
Duration of time in commercial sex (months)
<12	266 (18.0)	28 (6.7)	238 (22.4)	1.0 (Ref)
12–23	407 (27.5)	94 (22.5)	313 (29.4)	2.2 (1.5 to 3.2)
24–47	503 (34.0)	162 (38.8)	341 (32.1)	3.1 (2.1 to 4.4)
≥48	304 (20.5)	133 (31.9)	171 (16.1)	4.2 (2.9 to 6.0)	<0.001
Last working location
This city	395 (27.8)	91 (23.1)	304 (29.5)	1.0 (Ref)
Other city in this province	326 (26.4)	126 (32.0)	250 (24.3)	1.6 (1.3 to 2.0)		1.1 (1.01 to 1.2)	0.022
Other province	305 (21.4)	114 (29.0)	191 (18.6)	1.5 (1.2 to 1.8)		1.1 (0.9 to 1.3)	0.062
First time in this business	347 (24.4)	63 (16.0)	284 (27.6)	0.8 (0.6 to 1.1)	<0.001	1.0 (0.9 to 1.2)	0.629
Days per week in sex work
1–4	241 (16.2)	31 (7.4)	210 (19.6)	1.0 (Ref)
5	581 (39.1)	93 (22.3)	488 (45.6)	1.2 (0.9 to 1.8)		1.2 (0.8 to 1.8)	0.415
6–7	665 (44.7)	293 (70.3)	372 (34.8)	3.4 (2.4 to 4.8)	<0.001	1.7 (1.2 to 2.6)	0.008
Clients per day
1	314 (21.1)	31 (7.4)	283 (26.5)	1.0 (Ref)
2	555 (37.3)	156 (37.4)	399 (37.3)	2.8 (2.0 to 4.1)		2.1 (1.4 to 3.1)	<0.001
≥3	618 (41.6)	230 (55.2)	388 (36.3)	3.8 (2.7 to 5.3)	<0.001	2.2 (1.5 to 3.3)	<0.001
Had regular clients in the past year
No	689 (47.8)	144 (36.0)	578 (52.3)	1.0 (Ref)
Yes	753 (52.2)	256 (64.0)	625 (47.7)	1.6 (1.4 to 1.9)	<0.001

^*χ² test.

FSW, female sex workers; PR, prevalence ratio.