Table 2 Baseline characteristics stratified by nocturnal sleep duration: the Heinz Nixdorf Recall Study.

From: Associations between self-reported sleep characteristics and incident mild cognitive impairment: The Heinz Nixdorf Recall Cohort Study

Variable

 

Time asleep

≤ 5 h

> 5 h to < 7 h

7 h to < 8 h

8 h to < 9 h

≥ 9 h

N

 

209 (100.0%)

612 (100.0%)

655 (100.0%)

352 (100.0%)

62 (100.0%)

Sex

Female

138 (66.0%)

311 (50.8%)

336 (51.3%)

162 (46.0%)

26 (41.9%)

Age (years)

 

57.5 ± 7.2

56.7 ± 7.0

57.9 ± 7.0

60.2 ± 7.1

60.8 ± 6.1

Sleep Quality: PSQI Scorea

 

11.0 ± 3.4

6.6 ± 2.9

4.0 ± 2.1

3.4 ± 1.9

3.2 ± 1.9

> 5

197 (94.3%)

369 (60.3%)

134 (20.5%)

40 (11.4%)

7 (11.3%)

Difficulties Initiating Sleep

Sometimes

45 (21.5%)

231 (37.7%)

262 (40.0%)

130 (36.9%)

21 (33.9%)

Often

64 (30.6%)

125 (20.4%)

93 (14.2%)

28 (8.0%)

6 (9.7%)

Almost every Night

66 (31.6%)

43 (7.0%)

19 (2.9%)

8 (2.3%)

2 (3.2%)

Difficulties Maintaining Sleep

Sometimes

19 (9.1%)

142 (23.2%)

177 (27.0%)

114 (32.4%)

14 (22.6%)

Often

60 (28.7%)

164 (26.8%)

180 (27.5%)

92 (26.1%)

12 (19.4%)

Almost every Night

124 (59.3%)

255 (41.7%)

209 (31.9%)

104 (29.5%)

29 (46.8%)

Early-morning Awakening

Sometimes

45 (21.5%)

187 (30.6%)

227 (34.7%)

117 (33.2%)

19 (30.6%)

Often

62 (29.7%)

144 (23.5%)

98 (15.0%)

44 (12.5%)

1 (1.6%)

Almost every Night

62 (29.7%)

76 (12.4%)

25 (3.8%)

10 (2.8%)

3 (4.8%)

APOE ε4 Genotype

ε4 Carrierb

42 (20.1%)

152 (24.8%)

173 (26.4%)

85 (24.1%)

15 (24.2%)

Alcohol Consumption [g/week]

9.77 ± 17.39

9.8 ± 17.4

8.1 ± 13.8

8.9 ± 15.4

9.4 ± 16.2

 

Depression Scorec

 

9.1 ± 5.9

7.7 ± 5.9

6.7 ± 5.4

6.6 ± 5.4

6.5 ± 6.2

Framingham Risk Score

 

0.2 ± 0.2

0.2 ± 0.2

0.2 ± 0.2

0.3 ± 0.2

0.3 ± 0.2

Height [cm]

 

167.1 ± 9.4

169.4 ± 9.0

169.5 ± 9.3

169.5 ± 9.1

170.9 ± 9.0

ISCED [years]

 

13.9 ± 2.1

14.5 ± 2.4

14.5 ± 2.4

14.3 ± 2.3

13.8 ± 2.1

Physical Activity [MET-h/Week]

40.64 ± 44.81

40.6 ± 44.8

42.1 ± 39.3

45.6 ± 42.2

52.4 ± 55.2

 

Waist Circumference [cm]

 

92.3 ± 14.6

91.9 ± 12.8

92.4 ± 12.4

93.4 ± 12.3

95.7 ± 14.3

Smoking Status

Former Smoker

75 (35.9%)

240 (39.2%)

239 (36.5%)

128 (36.4%)

23 (37.1%)

Current Smoker

42 (20.1%)

126 (20.6%)

110 (16.8%)

83 (23.6%)

13 (21.0%)

  1. All numbers were derived from the complete case analysis dataset (N = 1890). Data is displayed as N (Col Percent) or Mean ± Standard Deviation. Reference Categories were omitted. Abbreviations: PSQI: Pittsburgh Sleep Quality Index; g: Gramm; cm: Centimetres; ISCED: International Standard Classification of Education; MET-h: Metabolic Equivalent of Task – hours, APOE. Apolipoprotein E.
  2. aScore > 5 indicates poor sleep quality bɛ4 carrier: at least one 4 allele (ɛ2/ɛ4, ɛ3/ɛ4, ɛ4/ɛ4) cCentre for Epidemiologic Studies Depression Scale, higher scores indicate higher levels of depression.
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