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Table 1 Baseline characteristics of participants by tertiles of WWI

From: Association between weight-adjusted waist-index and symptoms of sleep apnea in US adults: results from 2015–2018 national health and nutrition examination survey

Variable

WWI (cm/√kg)

Total n = 9,566 (%)

Tertile 1

Tertile 2

Tertile 3

p

Age (in years), n (%)

 < .01

 20—39

3127 (32.69)

1764 (55.33)

880 (27.59)

483 (15.15)

 

 40—59

3164 (33.08)

1014 (31.81)

1209 (37.91)

941 (29.51)

 

 60 + 

3275 (34.23)

410 (12.86)

1100 (34.50)

1765 (55.34)

 

Gender, n (%)

 < .01

 Males

4693 (49.06)

1878 (58.91)

1676 (52.56)

1139 (35.72)

 

 Females

4873 (50.94)

1310 (41.09)

1513 (47.44)

2050 (64.28)

 

Education, n (%)

 < .01

 Less than high School

2028 (21.22)

463 (14.53)

661 (20.73)

904 (28.40)

 

 High school or GED

2165 (22.65)

676 (21.21)

749 (23.49)

740 (23.25)

 

 Some college/AA degree

2974 (31.11)

1018 (31.94)

988 (30.98)

968 (30.41)

 

 College graduate/above

2392 (25.02)

1030 (32.32)

791 (24.80)

571 (17.94)

 

Race/Ethnicity, n (%)

 < .01

 Hispanics

2569 (26.86)

609 (19.10)

896 (28.10)

1064 (33.36)

 

 Non-Hispanic White

3227 (33.73)

1023 (32.09)

997 (31.26)

1207 (37.84)

 

 Non-Hispanic Black

2111 (22.07)

885 (27.76)

691 (21.67)

535 (16.78)

 

 Other

1659 (17.34)

671 (21.05)

605 (18.97)

383 (12.02)

 

Triglycerides (mg/dL), median (IQR)

91.37 (60.97—137.50)

71.70 (49.98—109.66)

98.78 (67.05—149.12)

109.58 (77.22—155.20)

 < .01

Alcohol drinks/day, past 12 months, median (IQR)

1.43 (1.00—2.47)

1.56 (1.00—2.66)

1.45 (1.00 -2.28)

1.15 (1.00 -204)

 < .01

Cigarette smoking, n (%)

 < .01

 Current

1790 (18.73)

690 (21.66)

605 (18.99)

495 (15.53)

 

 Former

2205 (23.07)

530 (16.64)

794 (24.92)

881 (27.63)

 

 Never

5564 (58.20)

1965 (61.70)

1787 (56.09)

1812 (56.84)

 

Physical Activity, n (%)

 < .01

 Active

3355 (35.07)

1402 (43.98)

1118 (35.06)

835 (26.18)

 

 Not active

6211 (64.93)

1786 (56.02)

2071 (64.94)

2354 (73.82)

 

Drug abuse, n (%)

0.38

 Yes

1232 (16.79)

492 (17.41)

421 (17.00)

319 (15.69)

 

 No

6104 (83.21)

2334 (82.59)

2056 (83.00)

1714 (84.31)

 

Asthma, n (%)

0.18

 Yes

1403 (14.68)

475 (14.91)

414 (12.99)

514 (16.13)

 

 No

8157 (85.32)

2711 (85.09)

2773 (87.01)

2673 (83.87)

 

Sleep Apnea symptoms, n (%)

 < .01

 Yes

1253 (13.10)

276 (8.66)

425 (13.33)

552 (17.31)

 

 No

8313 (86.90)

2912 (91.34)

2764 (86.67)

2637 (82.69)

 

Weight (kg), mean ± SD

83.64 ± 55.01

76.14 ± 30.49

85.65 ± 32.75

91.37 ± 48.57

 < .01

HC (cm), mean ± SD

107.54 ± 32.20

100.65 ± 15.71

108.32 ± 15.47

115.74 ± 35.34

 < .01

WC (cm), mean ± SD

100.37 ± 49.11

88.45 ± 21.46

102.23 ± 21.46

114.17 ± 29.93

 < .01

BMI (kg/m2), mean ± SD

29.45 ± 19.12

25.75 ± 9.03

29.94 ± 9.03

33.85 ± 15.81

 < .01

WtHR (cm/m), mean ± SD

59.76 ± 29.36

51.56 ± 11.29

60.60 ± 9.60

69.74 ± 16.83

 < .01

WHR (cm/cm), mean ± SD

0.93 ± 0.23

0.87 ± 0.10

0.95 ± 0.12

0.99 ± 0.12

 < .01

WWI (cm/√kg), mean ± SD

11.03 ± 2.37

10.20 ± 0.72

11.13 ± 0.40

12.05 ± 0.73

 < .01

  1. A p < .05 was considered statistically significant. All p-values for continuous variables were calculated using weighted linear regression. All p-values for categorical variables were determined using weighted chi-square (χ2) test. SD standard deviation, IQR interquartile range