Table 1 Prevalence of syphilis by demographic and behavioral characteristics and HIV infection (univariate analysis)

Total

7118

5.0 (4.5-5.5)

Age in years (median, interquartile range)

24 (16-56)

< 0.001

1.08 (1.07, 1.10)

Age group

< 0.001

16-19

1015

1.7 (1.0, 2.5)

1.0 (Reference)

20-29

4197

4.0 (3.0, 4.6)

2.42 (1.46, 4.00)

30-39

1519

7.8 (6.0, 9.2)

4.98 (2.97, 8.33)

40-

387

14.4 (11.0, 18.0)

9.85 (5.63, 17.23)

Province

< 0.001

Jiangsu

1791

3.6 (2.8-4.5)

1.0 (Reference)

Guangdong

1361

4.0 (2.9-5.0)

1.10 (0.76, 1.59)

Guangxi

2515

7.1 (6.1-8.1)

2.03 (1.52, 2.72)

Hainan

1451

3.9 (2.9-4.9)

1.10 (0.77, 1.59)

Site city

< 0.001

Yangzhou

929

0.8 (0.2-1.3)

1.0 (Reference)

Changzhou

862

6.7 (5.1-8.4)

9.49 (4.31, 20.92)

Jiangmen

533

3.0 (1.6-4.6)

4.07 (1.66, 9.95)

Maoming

828

4.6 (3.2-6.0)

6.39 (2.84, 14.38)

Wuzhou

1706

4.7 (3.7-5.7)

6.49 (2.99, 14.11)

Hezhou

809

12.2 (10.0-14.5)

18.33 (8.46, 39.69)

Qionghai

643

4.4 (2.8-5.9)

6.25 (2.71, 14.40)

Sanya

808

3.6 (2.3-4.9)

4.89 (2.13, 11.23)

Education

< 0.001

Primary or less

1140

9.4 (7.7-11.1)

4.42 (2.91, 6.72)

Junior high school

4727

4.6 (4.0-5.2)

2.04 (1.38, 3.02)

Senior high school and above

1243

2.3 (1.5-3.2)

1.0 (Reference)

Marital status

< 0.001

Never married

4262

3.5 (3.0-4.1)

1.0 (Reference)

Married

2641

7.0 (6.0-8.0)

2.08 (1.67, 2.59)

Separated/divorced/widowed

202

9.9 (5.8-14.0)

3.03 (1.86,4.95)

Ethnicity

0.452

Han

6263

5.0 (4.5-5.5)

1.0 (Reference)

Minority

827

5.6 (4.0-7.2)

1.13(0.82, 1.55)

Household registration(hukou)

0.322

Local

1859

4.6 (3.7-5.6)

1.0 (Reference)

Not local

5246

5.2 (4.6-5.8)

1.13(0.88, 1.46)

Typology

< 0.001

High-tier

2144

2.2 (1.6-2.9)

1.0 (Reference)

Middle-tier

3227

4.3 (3.6-5.0)

1.95 (1.40, 2.73)

Low-tier

1747

9.7 (8.3-11.1)

4.76 (3.43, 6.60)

Having had any STI symptoms past year

0.658

Yes

2892

4.9 (4.1-5.7)

0.95 (0.77, 1.18)

No

4200

5.1 (4.4-5.8)

1.0 (Reference)

Consistent condom use in past month

0.254

Yes

3282

5.4 (4.7-6.2)

1.14 (0.91,1.42)

No

3266

4.8 (4.0-5.5)

1.0 (Reference)

Injecting drug use

< 0.001

Yes

20

25.0 (6.0-44.0)

6.39 (2.31, 17.69)

No

7063

4.9 (4.4-5.4)

1.0 (Reference)

HIV infection

0.007

Positive

43

14.0 (3.6-24.3)

3.11 (1.30, 7.41)

Negative

7059

4.9 (4.4-5.5)

1.0 (Reference)