J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 16, Number 12, December 2024, pages 600-607

Simple Subjective Sleep Quality and Blood Pressure in Individuals With Optimal Sleep Duration: A Cross-Sectional Study

**Table 1.** Characteristics of the Study Participants^a From Yonaguni Island, Okinawa, Japan, Grouped According to Simple Subjective Sleep Quality
	Overall (N = 169)	Simple subjective sleep quality	P value for difference
The data are presented for the total participants, as well as for participants stratified according to age (≤ 49 or ≥ 50 years). Data are expressed as mean (standard deviation) or % (number) of participants in that category. The unpaired t-test or Chi-square test was used to compare the characteristics in the two subjective sleep quality groups. ^aThe study participants had a sleep duration of 6 - 7.9 h/day on weekdays and were not taking either sleep medication or antihypertensive medication.
Overall		N = 118	N = 51
Age, years	48.8 (15.0)	49.5 (14.4)	47.3 (16.4)	0.38
Females	53.9% (91)	55.1% (65)	51.0% (26)	0.66
Current alcohol drinking	41.4% (70)	39.0% (46)	47.1% (24)	0.33
Current smoking	18.3% (31)	19.5% (23)	15.7% (8)	0.56
Not-lowering salt intake	39.6% (67)	36.4% (43)	47.1% (24)	0.20
Body mass index, kg/m²	24.1 (5.0)	23.9 (4.8)	24.8 (5.5)	0.29
Sleep duration, h/day	6.8 (0.5)	6.9 (0.5)	6.7 (0.6)	0.17
Systolic blood pressure, mm Hg	125.7 (17.2)	124.7 (17.2)	127.9 (17.1)	0.26
Diastolic blood pressure, mm Hg	74.7 (11.3)	74.3 (11.0)	75.7 (12.0)	0.46
Aged ≤ 49 years	N = 93	N = 63	N = 30
Age, years	37.6 (7.6)	38.3 (7.6)	36.1 (7.5)	0.18
Females	50.5% (47)	50.8% (32)	50.0% (15)	0.94
Current alcohol drinking	45.2% (42)	46.0% (29)	43.3% (13)	0.81
Current smoking	20.4% (19)	22.2% (14)	16.7% (5)	0.53
Not-lowering salt intake	52.7% (49)	50.8% (32)	56.7% (17)	0.60
Body mass index, kg/m²	24.5 (5.9)	24.2 (5.6)	25.1 (6.5)	0.49
Sleep duration, h/day	6.8 (0.5)	6.9 (0.5)	6.7 (0.5)	0.12
Systolic blood pressure, mm Hg	121.0 (15.3)	118.4 (13.9)	126.4 (16.8)	0.02
Diastolic blood pressure, mm Hg	72.1 (11.3)	71.0 (10.5)	74.3 (12.8)	0.19
Aged ≥ 50 years	N = 76	N = 55	N = 21
Age, years	62.6 (9.3)	62.3 (8.3)	63.3 (11.6)	0.66
Females	57.9% (44)	60.0% (33)	52.4% (11)	0.55
Current alcohol drinking	36.8% (28)	30.9% (17)	52.4% (11)	0.08
Current smoking	15.8% (12)	16.4% (9)	14.3% (3)	0.82
Not-lowering salt intake	23.7% (18)	20.0% (11)	33.3% (7)	0.22
Body mass index, kg/m²	23.7 (3.6)	23.5 (3.7)	24.2 (3.5)	0.79
Sleep duration, h/day	6.8 (0.5)	6.8 (0.5)	6.8 (0.6)	0.38
Systolic blood pressure, mm Hg	131.4 (17.8)	131.8 (18.0)	130.1 (17.7)	0.36
Diastolic blood pressure, mm Hg	78.0 (10.5)	78.1 (10.5)	77.7 (10.7)	0.45

Table 1. Characteristics of the Study Participants^a From Yonaguni Island, Okinawa, Japan, Grouped According to Simple Subjective Sleep Quality

Overall (N = 169)

Simple subjective sleep quality

P value for difference

Good

Poor

The data are presented for the total participants, as well as for participants stratified according to age (≤ 49 or ≥ 50 years). Data are expressed as mean (standard deviation) or % (number) of participants in that category. The unpaired t-test or Chi-square test was used to compare the characteristics in the two subjective sleep quality groups. ^aThe study participants had a sleep duration of 6 - 7.9 h/day on weekdays and were not taking either sleep medication or antihypertensive medication.

Overall

N = 118

N = 51

Age, years

48.8 (15.0)

49.5 (14.4)

47.3 (16.4)

0.38

Females

53.9% (91)

55.1% (65)

51.0% (26)

0.66

Current alcohol drinking

41.4% (70)

39.0% (46)

47.1% (24)

0.33

Current smoking

18.3% (31)

19.5% (23)

15.7% (8)

0.56

Not-lowering salt intake

39.6% (67)

36.4% (43)

47.1% (24)

0.20

Body mass index, kg/m²

24.1 (5.0)

23.9 (4.8)

24.8 (5.5)

0.29

Sleep duration, h/day

6.8 (0.5)

6.9 (0.5)

6.7 (0.6)

0.17

Systolic blood pressure, mm Hg

125.7 (17.2)

124.7 (17.2)

127.9 (17.1)

0.26

Diastolic blood pressure, mm Hg

74.7 (11.3)

74.3 (11.0)

75.7 (12.0)

0.46

Aged ≤ 49 years

N = 93

N = 63

N = 30

Age, years

37.6 (7.6)

38.3 (7.6)

36.1 (7.5)

0.18

Females

50.5% (47)

50.8% (32)

50.0% (15)

0.94

Current alcohol drinking

45.2% (42)

46.0% (29)

43.3% (13)

0.81

Current smoking

20.4% (19)

22.2% (14)

16.7% (5)

0.53

Not-lowering salt intake

52.7% (49)

50.8% (32)

56.7% (17)

0.60

Body mass index, kg/m²

24.5 (5.9)

24.2 (5.6)

25.1 (6.5)

0.49

Sleep duration, h/day

6.8 (0.5)

6.9 (0.5)

6.7 (0.5)

0.12

Systolic blood pressure, mm Hg

121.0 (15.3)

118.4 (13.9)

126.4 (16.8)

0.02

Diastolic blood pressure, mm Hg

72.1 (11.3)

71.0 (10.5)

74.3 (12.8)

0.19

Aged ≥ 50 years

N = 76

N = 55

N = 21

Age, years

62.6 (9.3)

62.3 (8.3)

63.3 (11.6)

0.66

Females

57.9% (44)

60.0% (33)

52.4% (11)

0.55

Current alcohol drinking

36.8% (28)

30.9% (17)

52.4% (11)

0.08

Current smoking

15.8% (12)

16.4% (9)

14.3% (3)

0.82

Not-lowering salt intake

23.7% (18)

20.0% (11)

33.3% (7)

0.22

Body mass index, kg/m²

23.7 (3.6)

23.5 (3.7)

24.2 (3.5)

0.79

Sleep duration, h/day

6.8 (0.5)

6.8 (0.6)

0.38

Systolic blood pressure, mm Hg

131.4 (17.8)

131.8 (18.0)

130.1 (17.7)

0.36

Diastolic blood pressure, mm Hg

78.0 (10.5)

78.1 (10.5)

77.7 (10.7)

0.45

**Table 2.** Mean Blood Pressure in Participants^a Grouped According to Simple Subjective Sleep Quality
	Simple subjective sleep quality	P value
The data are presented for the total participants as well as for participants stratified according to age (≤ 49 or ≥ 50 years). ^aThe study participants had a sleep duration of 6 - 7.9 h/day on weekdays and were not taking either sleep medication or antihypertensive medication. The unpaired t-test or analysis of covariance was used to compare blood pressure in the two subjective sleep quality groups. Three different models of analysis of covariance were constructed as follows: model 1 was adjusted for age and sex; model 2 was adjusted for the same covariates used in model 1 in addition to alcohol drinking habit, smoking habit, behavior for lowering salt intake, and body mass index; and model 3 was adjusted for the same covariates used in model 2 in addition to sleep duration. CI: confidence interval.
Overall	N = 118	N = 51
Systolic blood pressure, mm Hg
Crude mean (95% CI)	124.7 (121.5 - 127.8)	127.9 (123.1 - 132.7)	0.26
Age and sex-adjusted mean (95% CI), model 1	128.7 (124.8 - 132.7)	132.6 (127.5 - 137.6)	0.15
Multivariate-adjusted mean (95% CI), model 2	126.2 (120.6 - 131.7)	128.9 (122.3 - 135.5)	0.28
Multivariate-adjusted mean (95% CI), model 3	126.2 (120.7 - 131.7)	128.5 (121.9 - 135.0)	0.36
Diastolic blood pressure, mm Hg
Crude mean (95% CI)	74.3 (72.3 - 76.3)	75.7 (72.3 - 79.1)	0.46
Age and sex-adjusted mean (95% CI), model 1	77.6 (75.0 - 80.2)	79.2 (75.9 - 82.6)	0.36
Multivariate-adjusted mean (95% CI), model 2	73.5 (69.9 - 77.2)	74.4 (70.1 - 78.8)	0.59
Multivariate-adjusted mean (95% CI), model 3	73.5 (69.9 - 77.2)	74.2 (69.9 - 78.6)	0.69
Aged ≤ 49 years	N = 63	N = 30
Systolic blood pressure, mm Hg
Crude mean (95% CI)	118.4 (114.9 - 121.9)	126.4 (120.1 - 132.6)	0.02
Age and sex-adjusted mean (95% CI), model 1	125.8 (121.6 - 130.0)	134.1 (128.8 - 139.5)	0.005
Multivariate-adjusted mean (95% CI), model 2	121.1 (114.8 - 127.4)	128.0 (121.0 - 135.0)	0.01
Multivariate-adjusted mean (95% CI), model 3	121.0 (114.7 - 127.3)	127.8 (120.7 - 134.9)	0.01
Diastolic blood pressure, mm Hg
Crude mean (95% CI)	71.0 (68.4 - 73.7)	74.3 (69.5 - 79.1)	0.19
Age and sex-adjusted mean (95% CI), model 1	75.2 (72.0 - 78.5)	79.3 (75.1 - 83.4)	0.07
Multivariate-adjusted mean (95% CI), model 2	68.7 (63.8 - 73.6)	72.0 (66.5 - 77.5)	0.12
Multivariate-adjusted mean (95% CI), model 3	68.7 (63.8 - 73.6)	71.8 (66.2 - 77.3)	0.14
Aged ≥ 50 years	N = 55	N = 21
Systolic blood pressure, mm Hg
Crude mean (95% CI)	131.8 (127.0 - 136.7)	130.1 (122.1 - 138.2)	0.71
Age and sex-adjusted mean (95% CI), model 1	131.9 (125.0 - 138.8)	129.8 (120.9 - 138.7)	0.66
Multivariate-adjusted mean (95% CI), model 2	129.9 (120.6 - 139.3)	126.5 (114.0 - 138.9)	0.45
Multivariate-adjusted mean (95% CI), model 3	130.6 (121.3 - 139.8)	126.9 (114.6 - 139.2)	0.43
Diastolic blood pressure, mm Hg
Crude mean (95% CI)	78.1 (75.2 - 80.9)	77.7 (72.8 - 82.6)	0.89
Age and sex-adjusted mean (95% CI), model 1	79.8 (75.7 - 83.9)	79.3 (74.0 - 84.5)	0.85
Multivariate-adjusted mean (95% CI), model 2	78.8 (73.1 - 84.4)	77.7 (70.2 - 85.2)	0.70
Multivariate-adjusted mean (95% CI), model 3	79.1 (73.5 - 84.7)	78.0 (70.5 - 85.4)	0.68

Table 2. Mean Blood Pressure in Participants^a Grouped According to Simple Subjective Sleep Quality

Simple subjective sleep quality

P value

Good

Poor

The data are presented for the total participants as well as for participants stratified according to age (≤ 49 or ≥ 50 years). ^aThe study participants had a sleep duration of 6 - 7.9 h/day on weekdays and were not taking either sleep medication or antihypertensive medication. The unpaired t-test or analysis of covariance was used to compare blood pressure in the two subjective sleep quality groups. Three different models of analysis of covariance were constructed as follows: model 1 was adjusted for age and sex; model 2 was adjusted for the same covariates used in model 1 in addition to alcohol drinking habit, smoking habit, behavior for lowering salt intake, and body mass index; and model 3 was adjusted for the same covariates used in model 2 in addition to sleep duration. CI: confidence interval.

Overall

N = 118

N = 51

Systolic blood pressure, mm Hg

Crude mean (95% CI)

124.7 (121.5 - 127.8)

127.9 (123.1 - 132.7)

0.26

Age and sex-adjusted mean (95% CI), model 1

128.7 (124.8 - 132.7)

132.6 (127.5 - 137.6)

0.15

Multivariate-adjusted mean (95% CI), model 2

126.2 (120.6 - 131.7)

128.9 (122.3 - 135.5)

0.28

Multivariate-adjusted mean (95% CI), model 3

126.2 (120.7 - 131.7)

128.5 (121.9 - 135.0)

0.36

Diastolic blood pressure, mm Hg

Crude mean (95% CI)

74.3 (72.3 - 76.3)

75.7 (72.3 - 79.1)

0.46

Age and sex-adjusted mean (95% CI), model 1

77.6 (75.0 - 80.2)

79.2 (75.9 - 82.6)

0.36

Multivariate-adjusted mean (95% CI), model 2

73.5 (69.9 - 77.2)

74.4 (70.1 - 78.8)

0.59

Multivariate-adjusted mean (95% CI), model 3

73.5 (69.9 - 77.2)

74.2 (69.9 - 78.6)

0.69

Aged ≤ 49 years

N = 63

N = 30

Systolic blood pressure, mm Hg

Crude mean (95% CI)

118.4 (114.9 - 121.9)

126.4 (120.1 - 132.6)

0.02

Age and sex-adjusted mean (95% CI), model 1

125.8 (121.6 - 130.0)

134.1 (128.8 - 139.5)

0.005

Multivariate-adjusted mean (95% CI), model 2

121.1 (114.8 - 127.4)

128.0 (121.0 - 135.0)

0.01

Multivariate-adjusted mean (95% CI), model 3

121.0 (114.7 - 127.3)

127.8 (120.7 - 134.9)

0.01

Diastolic blood pressure, mm Hg

Crude mean (95% CI)

71.0 (68.4 - 73.7)

74.3 (69.5 - 79.1)

0.19

Age and sex-adjusted mean (95% CI), model 1

75.2 (72.0 - 78.5)

79.3 (75.1 - 83.4)

0.07

Multivariate-adjusted mean (95% CI), model 2

68.7 (63.8 - 73.6)

72.0 (66.5 - 77.5)

0.12

Multivariate-adjusted mean (95% CI), model 3

68.7 (63.8 - 73.6)

71.8 (66.2 - 77.3)

0.14

Aged ≥ 50 years

N = 55

N = 21

Systolic blood pressure, mm Hg

Crude mean (95% CI)

131.8 (127.0 - 136.7)

130.1 (122.1 - 138.2)

0.71

Age and sex-adjusted mean (95% CI), model 1

131.9 (125.0 - 138.8)

129.8 (120.9 - 138.7)

0.66

Multivariate-adjusted mean (95% CI), model 2

129.9 (120.6 - 139.3)

126.5 (114.0 - 138.9)

0.45

Multivariate-adjusted mean (95% CI), model 3

130.6 (121.3 - 139.8)

126.9 (114.6 - 139.2)

0.43

Diastolic blood pressure, mm Hg

Crude mean (95% CI)

78.1 (75.2 - 80.9)

77.7 (72.8 - 82.6)

0.89

Age and sex-adjusted mean (95% CI), model 1

79.8 (75.7 - 83.9)

79.3 (74.0 - 84.5)

0.85

Multivariate-adjusted mean (95% CI), model 2

78.8 (73.1 - 84.4)

77.7 (70.2 - 85.2)

0.70

Multivariate-adjusted mean (95% CI), model 3

79.1 (73.5 - 84.7)

78.0 (70.5 - 85.4)

0.68