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Table 1 Response to Invitation and Participation in the Bremen Study Center of the German National Cohort

From: Study invitations with envelopes made from recycled paper do not increase likelihood of active responses or study participation in the German National Cohort

 

Active response (N = 3518)

Participation (N = 3447d)

No

Yesa

ORb (95% CI)

No

Yes

ORc (95% CI)

n

%

n

%

n

%

n

%

Envelope color

 White

1929

95.4

93

4.6

1

1766

89.0

218

11.0

1

 Grey

1418

94.8

78

5.2

1.16 (0.83, 1.62)

1308

89.4

155

10.6

0.95 (0.76, 1.19)

Sexe

 Female

1108

93.8

73

6.2

1

1003

86.2

161

13.8

1

 Male

2239

95.8

98

4.2

0.73 (0.53, 1.02)

2071

90.7

212

9.3

0.71 (0.57, 0.90)

Nationalitye

 Non-German

690

98.6

10

1.4

1

644

96.4

24

3.6

1

 German

2657

94.3

161

5.7

3.75 (2.07, 7.66)

2430

87.4

349

12.6

3.46 (2.31, 5.43)

Age

 20–29

339

96.0

14

4.0

1.41 (0.73, 2.56)

319

93.3

23

6.7

0.89 (0.54, 1.41)

 30–39

182

96.8

6

3.2

1.15 (0.43, 2.57)

177

95.7

8

4.3

0.58 (0.26, 1.15)

 40–49

1321

96.9

43

3.2

1

1233

91.9

109

8.1

1

 50–59

887

94.1

56

5.9

1.78 (1.19, 2.69)

784

85.0

138

15.0

1.83 (1.40, 2.40)

 60–69

618

92.2

52

7.8

2.25 (1.48, 3.43)

561

85.5

95

14.5

1.67 (1.24, 2.25)

N

3347

 

171

  

3074

 

373

  
  1. OR odds ratio, CI confidence interval
  2. aIncludes subjects who replied by letter, phone call, e-mail or visited the study center in person
  3. bAdjusted for pre-trial likelihood of active responses to invitation letter stratified by weekdays
  4. cAdjusted for pre-trial study participation stratified by weekdays
  5. dSubjects excluded from analysis (N = 71): recruitment not complete (N = 22), subject not eligible, not capable, or deceased (N = 49)
  6. eInformation provided by Bremen’s resident registration office
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BMC Research Notes

ISSN: 1756-0500

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