Table 2 Subgroup analyses for the effects of omega-3 supplementation on cognitive function.

Attention outcome

Overall

32

0.117 (-0.958, 1.193)

0.831

98.5

< 0.001

Intervention duration (weeks)

0.001

< 26

25

-0.054 (-0.211, 0.102)

0.498

92.5

< 0.001

26≤

7

0.456 (0.248, 0.665)

0.001

99.6

< 0.001

Age (years)

0.684

< 60

13

0.093 (-0.125, 0.310)

0.403

74.1

< 0.001

60≤

19

0.148 (-0.005, 0.301)

0.058

99.1

< 0.001

Location

0.001

America

15

-0.098 (-0.301, 0.105)

0.344

94.5

< 0.001

Europe

10

-0.153 (-0.353, 0.047)

0.135

99.4

< 0.001

Asia and Oceania

7

0.981 (0.720, 1.241)

0.001

95.5

< 0.001

Health status

0.141

Healthy

20

0.029 (-0.153, 0.212)

0.752

94.9

< 0.001

Cognitive disorders

12

0.218 (0.046, 0.389)

0.013

99.3

< 0.001

BMI

0.001

Normal

27

-0.028 (-0.186, 0.130)

0.726

93.4

< 0.001

Over weight

5

0.394 (0.190, 0.599)

0.001

99.8

< 0.001

Assessment tool

0.001

TMT A

10

-0.081 (-0.259, 0.096)

0.370

99.5

< 0.001

Stroop

14

0.725 (0.439, 1.011)

0.001

93.8

< 0.001

Other tools

8

0.099 (-0.126, 0.323)

0.388

61.9

0.010

Co-intervention

0.001

Yes

10

0.469 (0.291, 0.648)

0.001

92.3

0.010

No

22

-0.199 (-0.375, -0.024)

0.026

99.5

< 0.001

Executive function outcome

Overall

39

0.520 (-0.159, 1.212)

0.132

98.6

< 0.001

Intervention duration (weeks)

0.003

< 48

29

0.384 (0.286, 0.482)

0.001

97.2

< 0.001

48≤

10

0.162 (0.043, 0.282)

0.008

99.5

< 0.001

Age (years)

0.405

< 49

4

0.235 (0.062, 0.409)

0.008

76.6

0.005

49≤

35

0.309 (0.225, 0.393)

0.001

98.7

< 0.001

Location

0.001

America

12

0.062 (-0.046, 0.171)

0.259

97.8

< 0.001

Europe

15

0.287 (0.160, 0.413)

0.001

99.3

< 0.001

Asia and Oceania

12

1.074 (0.878, 1.269)

0.001

95.3

< 0.001

Health status

0.001

Healthy

25

0.213 (0.125, 0.301)

0.001

97.6

< 0.001

Cognitive disorders

14

0.530 (0.381, 0.679)

0.001

99.2

< 0.001

BMI

0.001

Normal

14

-0.371 (-0.583, -0.158)

0.001

95.7

< 0.001

Over weight

25

0.399 (0.318, 0.480)

0.001

99.0

< 0.001

Sex

0.001

Males and females

34

0.319 (0.242, 0.396)

0.001

98.7

< 0.001

Females

5

-0.482 (-0.917, -0.048)

0.03

48.4

0.10

Assessment tool

0.001

TMT B

12

0.531 (0.384, 0.679)

0.001

99.5

< 0.001

Stroop

6

0.332 (0.132, 0.533)

0.001

93.6

< 0.001

Other tools

21

0.192 (0.090, 0.290)

0.001

93.8

< 0.001

Co-intervention

0.001

Yes

14

-0.038 (-0.153, 0.077)

0.515

99.2

< 0.001

No

26

0.560 (0.460, 0.661)

0.001

97.6

< 0.001

Perceptual speed outcome

Overall

34

0.444 (-0.014, 0.901)

0.057

96.4

< 0.001

Intervention duration (weeks)

0.075

< 48

20

0.478 (0.367, 0.590)

0.001

96.9

< 0.001

48≤

14

0.350 (0.241, 0.460)

0.001

95.6

< 0.001

Age (years)

0.001

< 60

12

0.619 (0.492, 0.747)

0.001

98.0

< 0.001

60≤

22

0.290 (0.191, 0.388)

0.001

93.9

< 0.001

Location

0.006

Asia and Oceania

17

0.570 (0.425, 0.716)

0.001

95.8

< 0.001

Europe and America

17

0.350 (0.257, 0.442)

0.001

97.0

< 0.001

Health status

0.020

Healthy

22

0.491 (0.393, 0.590)

0.001

96.3

< 0.001

Cognition disorders

12

0.279 (0.150, 0.408)

0.001

96.7

< 0.001

BMI

0.676

Normal

16

0.413 (0.206, 0.619)

0.001

97.0

< 0.001

Over weight

18

0.413 (0.329, 0.498)

0.001

95.8

< 0.001

Sex

0.001

Males and females

31

0.421 (0.343, 0.499)

0.001

98.3

< 0.001

Males

3

-3.871 (-5.694, -2.049)

0.001

96.1

< 0.001

Co-intervention

0.001

Yes

9

-0.131 (-0.286, 0.024)

0.099

98.0

< 0.001

No

25

0.598 (0.507, 0.688)

0.001

94.7

< 0.001

Language outcome

Overall

26

0.976 (0.413, 1.539)

0.001

96.8

< 0.001

Intervention duration (weeks)

0.001

< 48

12

0.784 (0.654, 0.914)

0.001

97.9

< 0.001

48≤

14

-0.161 (-0.282, -0.039)

0.010

91.6

< 0.001

Age (years)

0.001

< 60

3

0.838 (0.688, 0.989)

0.001

99.5

< 0.001

60≤

23

-0.018 (-0.129, 0.092)

0.744

92.3

< 0.001

Location

0.001

Europe and America

16

0.401 (0.293, 0.508)

0.001

97.8

< 0.001

Asia and Oceania

10

0.022 (-0.136, 0.180)

0.785

87.2

< 0.001

Health status

Healthy

12

0.540 (0.414, 0.667)

0.001

98.2

< 0.001

Cognitive disorders

14

0.030 (-0.095, 0.155)

0.638

91.0

< 0.001

BMI

Normal

12

1.073 (0.762, 1.383)

0.001

97.8

< 0.001

Over weight

14

0.210 (0.117, 0.303)

0.001

94.8

< 0.001

Assessment tool

Verbal fluency

6

-0.476 (-0.778, -0.175)

0.002

95.9

< 0.001

Other tools

20

0.353 (0.260, 0.446)

0.001

97.0

< 0.001

Co-intervention

Yes

10

0.043 (-0.135, 0.222)

0.001

97.9

< 0.001

No

16

0.359 (0.257, 0.462)

0.001

95.5

< 0.001

Episodic memory outcome

Overall

103

0.265 (-0.058, 0.588)

0.108

92.9

< 0.001

Intervention duration (weeks)

< 48

86

0.423 (0.337, 0.508)

0.001

83.9

< 0.001

48≤

17

-0.286 (-0.405, -0.167)

0.001

98.1

< 0.001

Age (years)

< 60

31

0.532 (0.430, 0.634)

0.001

82.8

< 0.001

60≤

72

-0.119 (-0.213, -0.024)

0.014

94.0

< 0.001

Location

America

40

0.373 (0.283, 0.463)

0.001

82.6

< 0.001

Europe

42

-0.255 (-0.375, -0.136)

0.001

95.5

< 0.001

Asia and Oceania

21

0.659 (0.392, 0.927)

0.001

90.8

< 0.001

Health status

Healthy

69

0.280 (0.202, 0.357)

0.001

90.3

< 0.001

Cognitive disorders

34

-0.211 (-0.366, -0.055)

0.008

95.4

< 0.001

BMI

Normal

63

0.231 (0.086, 0.375)

0.002

85.1

< 0.001

Over weight

40

0.167 (0.088, 0.246)

0.001

96.2

< 0.001

Sex

0.153

Males and females

90

0.187 (0.118, 0.257)

0.001

93.5

< 0.001

Females

13

-0.282 (-0.922, 0.358)

0.387

82.4

< 0.001

Co-intervention

Yes

23

-0.258 (-0.373, -0.143)

0.001

96.8

< 0.001

No

80

0.434 (0.347, 0.521)

0.001

88.1

< 0.001

Primary memory outcome

Overall

20

0.768 (0.059, 1.477)

0.034

96.2

< 0.001

Intervention duration (weeks)

< 48

13

0.189 (-0.028, 0.407)

0.021

63.0

< 0.001

48≤

7

1.144 (0.984, 1.304)

0.001

98.6

< 0.001

Location

America

2

0.610 (0.018, 1.201)

0.043

0.0

0.829

Europe

10

-0.054 (-0.213, 0.106)

0.509

60.6

0.007

Asia and Oceania

8

2.718 (2.483, 2.953)

0.001

94.0

< 0.001

Health status

Healthy

15

0.004 (-0.149, 0.158)

0.955

55.2

0.005

Cognitive disorders

5

2.741 (2.503, 2.978)

0.001

96.5

< 0.000

BMI

Normal

6

1.054 (0.466, 1.642)

0.001

8.3

0.363

Over weight

14

0.797 (0.665, 0.929)

0.001

97.4

< 0.001

Assessment tool

Digit span

15

0.972 (0.822, 1.120)

0.001

97.0

< 0.001

Other tools (recall)

5

0.372 (0.112, 0.631)

0.005

0.0

0.848

Co-intervention

Yes

5

-0.126 (-0.461, 0.209)

0.460

55.5

0.061

No

15

0.972 (0.833, 1.112)

0.001

97.0

0.001

Visuospatial functions outcome

Overall

15

0.893 (0.452, 1.333)

0.001

97.4

< 0.001

Intervention duration (weeks)

< 48

6

2.038 (1.739, 2.338)

0.001

98.0

< 0.001

48≤

9

0.364 (0.295, 0.433)

0.001

95.1

< 0.001

Location

America and Europe

3

4.236 (3.768, 4.703)

0.001

98.1

< 0.001

Asia

12

0.368 (0.300, 0.436)

0.001

93.4

< 0.001

Health status

Healthy

3

4.236 (3.768, 4.703)

0.001

98.1

< 0.001

Cognitive disorders

12

0.368 (0.300, 0.436)

0.001

93.4

< 0.001

BMI

Normal

6

2.038 (1.739, 2.338)

0.001

98.0

< 0.001

Over weight

9

0.364 (0.295, 0.433)

0.001

95.1

< 0.001

Assessment tool

Block design

4

0.041 (-0.080, 0.171)

0.482

37.5

0.171

Picture arrangement

3

0.122 (-0.002, 0.253)

0.059

87.8

< 0.001

Picture completion

3

0.881 (0.747, 1.032)

0.001

81.7

0.001

Other tools

5

0.852 (0.712, 0.980)

0.001

98.9

< 0.001

Co-intervention

Yes

1

2.735 (2.033, 3.437)

0.001

-

-

No

14

0.427 (0.360, 0.495)

0.001

97.3

< 0.001

Global cognitive ability outcome

Overall

60

1.001 (0.650, 1.353)

0.001

97.1

< 0.001

Intervention duration (weeks)

< 48

33

0.276 (0.168, 0.383)

0.001

93.4

< 0.001

48≤

27

-0.137 (-0.203, -0.071)

0.001

98.3

< 0.001

Age (years)

< 60

10

0.173 (0.012, 0.335)

0.036

62.7

0.004

60≤

50

-0.041 (-0.101, 0.012)

0.161

97.4

< 0.001

Location

America

17

-0.469 (-0.555, -0.384)

0.001

96.1

< 0.001

Europe

17

0.214 (0.112, 0.315)

0.001

73.1

< 0.001

Asia and Oceania

26

0.463 (0.341, 0.565)

0.001

98.2

< 0.001

Health status

Healthy

19

0.071 (-0.021, 0.163)

0.131

96.3

< 0.001

Cognitive disorders

41

-0.079 (-0.151, -0.008)

0.029

97.4

< 0.001

BMI

Normal

30

0.322 (0.207, 0.437)

0.001

96.4

< 0.001

Over weight

30

-0.131 (-0.196, -0.067)

0.001

97.5

< 0.001

Co-intervention

Yes

15

0.141 (0.026, 0.255)

0.016

96.8

< 0.001

No

45

-0.075 (-0.140, -0.011)

0.022

97.2

< 0.001