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Table 1 Characteristics of the participating cohorts in analyses of cord blood DNAm and child sleep outcomes

From: Longitudinal associations of DNA methylation and sleep in children: a meta-analysis

 

ALSPAC

EDEN

Generation R

Healthy Start

INMA

LINA

MoBa-1

MoBa-2

PREDO

PROGRESS

Viva

Country

UK

France

Netherlands

USA

Spain

Germany

Norway

Norway

Finland

Mexico

USA

Children with DNAm at birth and sleep data, n

855

122

597

283

260

204

711

415

247

244

410

DNAm array type for cord blood

450 K

450 K

450 K

450 K

450 K

450 K

450 K

450 K

450 K

EPIC

450 K

Parent-reported child sleep

Number of children with data, n (%)

755 a

122

252 b

283

260

203 c

711

415

247

0

410

Child age at assessment, years, mean (SD)

11.7 (0.1)

5.7 (0.1)

11.7 (0.2)

4.7 (0.6)

11.1 (0.5)

10.1 (0.3)

7.0 (0.2)

7.1 (0.3)

3.9 (0.7)

n/a

7.8 (0.7)

Duration, hours, mean (SD)

9.9 (0.6)

10.8 (0.5)

9.5 (0.7)

9.4 (0.9)

9.5 (0.5)

9.5 (0.9)

10.2 (0.7)

10.1 (0.7)

10.2 (0.7)

n/a

9.8 (0.9)

Initiation difficulties, yes, n (%)

434 (53.1)

46 (37.4)

150 (23.4)

87 (30.7)

222 (85.4)

34 (16.7)

n/a

n/a

82 (33.2)

n/a

n/a

Sleep fragmentation, yes, n (%)

86 (10.8)

43 (35.0)

n/a

32 (11.3)

42 (16.2)

n/a

n/a

n/a

87 (35.2)

n/a

n/a

Actigraphy-estimated child sleep

Number of children with data, n (%)

0

0

257

0

81

0

0

0

0

244

0

Child age at assessment, years, mean (SD)

n/a

n/a

11.7 (0.2)

n/a

11.1 (0.5)

n/a

n/a

n/a

n/a

4.7 (0.5)

n/a

Duration (total sleep time), hours, mean (SD)

n/a

n/a

7.6 (0.7)

n/a

7.2 (1.0)

n/a

n/a

n/a

n/a

8.0 (0.6)

n/a

Sleep-onset latency, minutes, mean (SD)

n/a

n/a

42 (46.8)

n/a

6.8 (15.4)

n/a

n/a

n/a

n/a

10.6 (10.6)

n/a

Wake-after-sleep-onset duration, minutes, mean (SD)

n/a

n/a

86.0 (33.0)

n/a

41.2 (23.3)

n/a

n/a

n/a

n/a

102.8 (33.0)

n/a

Maternal characteristics

Education, low, n (%) d

417 (49.8)

29 (23.6)

48 (7.5)

92 (32.5)

63 (24.2)

4 (2.0)

258 (36.3)

157 (37.8)

13 (5.3)

103 (42.2)

6 (1.5)

Age, years, mean (SD)

30.1 (4.4)

30.3 (5.0)

31.9 (3.8)

27.3 (6.1)

30.6 (4.0)

30.8 (4.6)

29.9 (4.3)

30.3 (4.4)

33.5 (5.8)

28.2 (5.4)

32.3 (5.2)

Smoking during pregnancy, n (%)

 No smoking during pregnancy

727 (87.2)

94 (76.4)

506 (79.1)

241 (85.2)

187 (71.9)

201 (98.5)

521 (73.7)

316 (76.1)

234 (94.7)

n/a

374 (91.2)

 Smoked during pregnancy

107 (12.8)

29 (23.6)

134 (20.9)

42 (14.8)

73 (28.1)

3 (1.5)

190 (26.7)

99 (23.9)

13 (5.3)

n/a

36 (8.8)

  Quit in early pregnancy

27 (3.2)

9 (7.3)

61 (9.5)

20 (7.1)

40 (15.4)

n/a

99 (13.9)

62 (14.9)

9 (3.6)

n/a

n/a

  Continued smoking

80 (9.6)

20 (16.3)

73 (11.4)

22 (7.8)

33 (12.7)

n/a

91 (12.8)

37 (8.9)

4 (1.6)

n/a

n/a

Child characteristics

Sex, female, n (%)

441 (51.6)

52 (42.3)

319 (49.8)

134 (47.3)

123 (47.3)

97 (47.5)

328 (46.1)

188 (45.3)

117 (47.4)

112 (45.9)

199 (48.5)

Gestational age, weeks, mean (SD)

39.5 (1.5)

39.4 (1.5)

40.2 (1.4)

39.4 (1.2)

39.8 (1.3)

39.8 (1.4)

39.6 (1.5)

39.4 (1.6)

39.7 (3.1)

38.4 (1.6)

39.7 (1.6)

  1. 450 K Illumina Infinium® HumanMethylation450 BeadChip; DNAm deoxyribonucleic acid methylation; EPIC Illumina Infinium® HumanMethylationEPIC BeadChip; kg kilogram; n number of participants; n/a not applicable due to lack of available data; SD standard deviation; UK United Kingdom; USA United States of America
  2. aIn ALSPAC, sample size and age varied per outcome: of those with DNAm data at birth, 755 children had data on parent-reported sleep duration at the mean age of 11.7 years (SD = 0.1), while 791 and 769 children had data on parent-reported sleep initiation and fragmentation problems at the age of 9.6 years (SD = 0.1), respectively
  3. bIn Generation R, sample size and age varied per outcome: of those with DNAm data at birth, 252 children had data on parent-reported sleep duration at the mean age of 11.7 years (SD = 0.2), while 597 children had data on parent-reported sleep initiation problems at the mean age of 9.7 years (SD = 0.3)
  4. cIn LINA, 203 children had data on parent-reported sleep duration and 204 children had data on parent-reported sleep initiation problems
  5. dRates of low education are not directly comparable, as educational systems differed between countries and cohorts used different definitions of low education, as explained in more detail in Additional file 2: Methods
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Clinical Epigenetics

ISSN: 1868-7083

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