Table 1 Sample characteristics of problematic Internet use (PIU), n (%)

Gender

Male

7 734(49.8)

804(10.4)

106.67

<0.001

Female

7 804(50.2)

458(5.9)

Grade

Junior High school

4 758(30.6)

395(8.3)

16.54

<0.001

Senior High school

5 719(36.8)

517(9.0)

College

5 061(32.6)

350(6.9)

Residential background

Rural

6 297(40.5)

415(6.6)

33.28

<0.001

Urban

9 241(59.5)

847(9.2)

Area

Eastern area

5 866(37.8)

570(9.7)

84.56

<0.001

Middle area

5 254(33.8)

279(5.3)

Western area

4 418(28.4)

413(9.3)

Self-report family economy

Lower

2 746(17.7)

237(8.6)

19.16

<0.001

Middle

10 250(66.0)

769(7.5)

Upper

2 542(16.4)

256(10.1)

Service type mostly used

Information searching

2 291(14.7)

42(1.8)

361.52

<0.001

Entertainment

7 279(46.8)

764(10.5)

Chatting

3 165(20.4)

145(4.6)

Relieving loneliness

1 652(10.6)

254(15.4)

Others

1 151(7.4)

57(5.0)

Frequency of Internet use

≤ 4 times/week

13 056(84.0)

770(5.9)

541.92

<0.001

≥ 5 times/week

2 482(16.0)

492(19.8)