Table 4 Moderators used in subgroup and metaregression analyses.

From: Dose–response effects of light therapy on sleepiness and circadian phase shift in shift workers: a meta-analysis and moderator analysis

Study

Age (mean or range)

Female (n)

Sample size (n)

Shift work

Simulated shift

Research design

Data handling

Timing of treatment

Treatment day

Measure period

Babkoff 2002

24.6

5

12

Night

Simulated

RCT

PP or unknown

Night time

Same day

Night time

Bjorvatn 2007

42

1

17

Rotating

No

Crossover

PP or unknown

Day or mixed

Different day

Night time

Bjorvatn 2020

35.4

28

35

Night

No

Crossover

PP or unknown

Night time

Different day

Day or mixed

Boivin 2012

30.06

8

17

Rotating

No

RCT

ITT

Day or mixed

Different day

Day or mixed

Comtet 2019

24.78

5

18

Night

Simulated

Crossover

PP or unknown

Day or mixed

Same day

Day or mixed

Dawson 1991

21.2

6

13

Night

Simulated

RCT

ITT

Night time

Different day

Night time

Dawson 1995

23.6

NA

16

Night

Simulated

RCT

ITT

Night time

Different day

Night time

Griepentrog 2018

26–32

22

43

Night

No

Crossover

ITT

Day or mixed

Same day

Night time

Horowitz 2001

26.99

27

54

Rotating

Simulated

RCT

PP or unknown

Day or mixed

Different day

Day or mixed

Karchani 2011

30.415

0

90

Rotating

No

Crossover

ITT

Night time

Same day

Night time

Kretschmer 2013

58.5

50

32

Night

Simulated

RCT

ITT

Night time

Different day

Day or mixed

Lee 2006

24.5

12

23

Night

Simulated

RCT

PP or unknown

Night time

Different day

Day or mixed

Lee 2020

20.65

0

24

Night

Simulated

Crossover

PP or unknown

Day or mixed

Same day

Night time

Lowden 2004

36.2

1

18

Rotating

No

Crossover

ITT

Day or mixed

Different day

Day or mixed

Nagashima 2017

24.8

0

12

Night

Simulated

Crossover

PP or unknown

Day or mixed

Same day

Night time

Sadeghniiat-Haghighi 2011

33

0

94

Rotating

No

Crossover

PP or unknown

Night time

Same day

Night time

Smith 2009

25.79

11

19

Night

Simulated

RCT

ITT

Night time

Different day

Day or mixed

Sunde 2020

19–30

24

36

Night

Simulated

Crossover

PP or unknown

Night time

Different day

Night time

Tanaka 2011

29.7

61

61

Rotating

No

Crossover

ITT

Day or mixed

Different day

Day or mixed

Thorne 2010

46.5

0

10

Night

No

Crossover

PP or unknown

Day or mixed

Different day

Night time

Yoon 2002

21–24

12

12

Night

No

Crossover

ITT

Day or mixed

Different day

Night time

Study

Control intervention

Treatment light

Light intensity of EG (lux)

Treatment duration (daily hour)

Treatment duration (total hour)

Daily treatment session (n)

Lux-hours (per 1000)

   

Babkoff 2002

Dim light

Mixed

3000

1

1

1

3.00

   

Bjorvatn 2007

No

Single

10,000

0.5

4

1

40.00

   

Bjorvatn 2020

Dim Red light

Single

10,000

0.5

1.5

1

15.00

   

Boivin 2012

No

Single

NA

6

42

1

NA

   

Comtet 2019

Dim light

Single

10,000

0.5

0.5

1

5.00

   

Dawson 1991

Dim light

Single

6175

8

24

1

148.20

   

Dawson 1995

Dim light

Single

5500

4

12

1

66.00

   

Griepentrog 2018

Standard light

Mixed

1750

10

10

1

17.50

   

Horowitz 2001

Room light

Single

2500

6

18

1

45.00

   

Karchani 2011

Room light

Single

2750

1

1

4

2.75

   

Kretschmer 2013

Room light

Mixed

3300

2

6

1

19.80

   

Lee 2006

Dim light

Single

3500

1.25

2.5

5

8.75

   

Lee 2020

Dim light

Single

430

4.17

4.17

5

1.79

   

Lowden 2004

Room light

Single

2500

NA

NA

NA

NA

   

Nagashima 2017

Dim light

Single

3000

6

6

1

18.00

   

Sadeghniiat-Haghighi 2011

Room light

Single

2500

0.67

0.67

2

1.68

   

Smith 2009

Room light

Mixed

4100

1

8

4

32.80

   

Sunde 2020

Standard light

Single

900

6

18

1

16.20

   

Tanaka 2011

No

Single

7135

0.17

5

1

35.68

   

Thorne 2010

No

Single

3000

1

4

1

12.00

   

Yoon 2002

Room light

Mixed

15,000

5

15

1

225.00

   
  1. RCT randomized controlled trial, Crossover randomized crossover trial, ITT intention-to-treat, PP per protocol.