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Table 1 Exposure variables at baseline

From: Computer use and stress, sleep disturbances, and symptoms of depression among young adults – a prospective cohort study

Category

Variables and response categories

Men N = 1458

Women N = 2705

  

n

%

n

%

 

Computer use (CU)

    

Low

<2 hours per day

382

26

993

37

Medium

2–4 hours per day

505

35

950

35

High

>4 hours per day

564

39

748

28

 

Email/chat use

    

Low

Not at all

120

8

162

6

 

<1 hour per day

906

62

1732

64

Medium

1–2 hours per day

277

19

558

21

High

>2 hours per day

151

10

236

9

 

Computer gaming

    

Low

Not at all

655

45

2050

76

 

<1 hour per day

427

29

468

17

Medium

1–2 hours per day

204

14

114

4

High

>2 hours per day

168

12

61

2

 

CU without breaks

    

Low

Never

202

14

565

21

 

Only occasionally

314

22

832

31

Medium

A few times per month

247

17

526

20

 

A few times per week

324

22

445

17

High

Almost every day

366

25

323

12

 

CU causing lost sleep

 

Low

Never

410

28

1128

42

 

Only occasionally

490

34

920

34

Medium

A few times per month

316

22

393

15

High

A few times per week

181

12

206

8

 

Almost every day

57

4

46

2

 

Mobile phone use

    

Low

0–5 calls + 0–5 SMSs per day

804

55

1433

53

Medium

0–5 calls + 6–10 SMSs, or vice versa

326

22

616

23

High

>11 calls and/or >11 SMSs, or

323

22

645

24

 

6–10 calls + 6–10 SMSs per day

    
  1. Frequencies and percentages in exposure variables, including categorizations into low, medium, and high, are presented. Missing values (non-responses to items) are not accounted for, which means that the n varies for the variables.
  2. Questionnaire items: Computer use (CU): On average, how much time per day have you used on a computer (total use)? Email/chat use: On average, how much time per day have you used on a computer for emailing and chatting (leisure/private use)? Computer gaming: On average, how much time per day have you spent on computer gaming (e.g., computer games or online games, private/leisure use)? CU without breaks: How often have you used a computer for more than 2 hours without taking a break longer than 10 minutes? CU causing lost sleep: How often have you lost sleep because of sitting late at night at the computer? Mobile phone use: How many mobile phone calls on average have you made and received per day?, and How many SMS messages on average have you sent and received per day? The time span for all items was “over the past 30 days”.