Table 2 Demographic, lifestyle and clinical characteristics of subjects by tertiles of irisin

Irisin (ng/mL)

0.13 (0.02, 1.56)

4.73 (3.83, 5.97)

10.38 (8.67, 12.17)

23.05 (17.73, 31.28)

7.26 (2.75, 14.72)

<0.001‡

Demographics

N (%)

279 (25.0%)

279 (25.0%)

279 (25.0%)

278 (25.0%)

1115 (100.0%)

Sex

Male (n, %)

94 (33.7%)

100 (35.8%)

85 (30.5%)

70 (25.2%)

349 (31.3%)

0.039*

Female (n, %)

185 (66.3%)

179 (64.2%)

194 (69.5%)

208 (74.8%)

766 (68.7%)

Age (years)

53.2 ± 7.4

52.6 ± 7.4

53.4 ± 7.1

53.5 ± 7.0

53.2 ± 7.2

0.7

Education categories, (n, %)

0.4

Illiteracy

66 (23.7%)

70 (25.1%)

91 (32.6%)

75 (27.0%)

302 (27.1%)

Elementary school

87 (31.2%)

77 (27.6%)

77 (27.6%)

89 (32.0%)

330 (29.6%)

Middle school

67 (24.0%)

77 (27.6%)

52 (18.6%)

60 (21.6%)

256 (23.0%)

High school

35 (12.5%)

33 (11.8%)

38 (13.6%)

36 (13.0%)

142 (12.7%)

College or above

24 (8.6%)

22 (7.9%)

21 (7.5%)

18 (6.4%)

85 (7.6%)

Life style

Ever smoking (n, %)

82 (29.4%)

81 (29.0%)

73 (26.2%)

59 (21.2%)

295 (26.5%)

0.1

Ever drinking (n, %)

37 (13.3%)

27 (9.7%)

36 (12.9%)

30 (10.8%)

130 (11.7%)

0.4

Physical activity (MET-h/week)

84.0 (46.2, 158.2)

84.0 (46.2, 140.0)

87.3 (46.2, 152.4)

100.3 (56.0, 154.0)

84.0 (51.6, 148.4)

0.4

Body composition indices

BMI (kg/m2)

27.5 ± 3.1

27.3 ± 3.1

27.7 ± 3.3

27.2 ± 2.8

27.5 ± 3.1

0.2

Waist circumference (cm)

94.1 ± 7.3

93.8 ± 7.2

93.4 ± 7.1

93.1 ± 6.6

93.6 ± 7.1

0.4

Waist hip ratio

0.940 ± 0.049

0.943 ± 0.050

0.933 ± 0.050

0.930 ± 0.049

0.937 ± 0.049

0.006†

Body fat mass (kg)

24.0 ± 5.4

23.3 ± 5.3

24.1 ± 5.6

24.0 ± 5.1

23.9 ± 5.3

0.2

Body fat rate (%)

34.6 ± 6.6

34.0 ± 6.9

35.1 ± 7.0

35.3 ± 6.3

34.7 ± 6.7

0.1

Body fat free weight (kg)

46.7 ± 9.2

46.2 ± 8.4

45.8 ± 8.5

44.8 ± 7.5

45.9 ± 8.4

0.1

Muscle mass (kg)

44.1 ± 8.8

43.7 ± 8.1

43.2 ± 8.1

42.2 ± 7.2

43.3 ± 8.1

0.048*

Clinical characteristics

Systolic blood pressure (mmHg)

133.9 ± 17.5

133.1 ± 17.6

135.7 ± 20.1

133.1 ± 16.0

134.0 ± 17.9

0.3

Diastolic blood pressure (mmHg)

80.1 ± 10.7

80.0 ± 10.8

80.4 ± 12.1

79.0 ± 9.6

79.9 ± 10.8

0.4

Serum albumin (g/L)

49.1 ± 2.4

48.9 ± 2.4

49.0 ± 2.3

49.2 ± 2.5

49.0 ± 2.5

0.8

Serum glubulin (g/L)

25.0 ± 3.2

25.7 ± 3.4

26.5 ± 3.7

26.8 ± 3.4

26.0 ± 3.4

<0.001‡

Triglyceride (mmol/L)

1.94 ± 1.44

1.98 ± 1.34

1.81 ± 1.16

1.77 ± 1.15

1.87 ± 1.28

0.2

Total cholesterol (mmol/L)

5.83 ± 1.10

5.77 ± 1.00

5.91 ± 1.11

5.95 ± 1.13

5.87 ± 1.09

0.2

HDL-cholesterol (mmol/L)

1.36 ± 0.30

1.35 ± 0.31

1.36 ± 0.28

1.39 ± 0.30

1.37 ± 0.30

0.6

LDL-cholesterol (mmol/L)

3.59 ± 1.02

3.54 ± 0.96

3.73 ± 1.03

3.76 ± 1.03

3.65 ± 1.01

0.022*

Fasting glucose (mmol/L)

6.22 ± 1.95

6.09 ± 1.69

6.23 ± 1.95

6.09 ± 1.35

6.16 ± 1.75

0.6

Glucose 120 min OGTT (mmol/L)

9.11 ± 4.17

8.93 ± 4.09

9.16 ± 4.24

9.01 ± 3.90

9.05 ± 4.10

0.9

Fasting insulin (mIU/L)

13.2 ± 7.2

12.6 ± 6.8

12.5 ± 6.4

12.7 ± 6.6

12.7 ± 6.8

0.6

HOMA-IR (*10-6 mol*IU*L-2)

3.68 ± 2.37

3.49 ± 2.59

3.51 ± 2.22

3.50 ± 2.21

3.54 ± 2.35

0.7

HbA1c

6.27 ± 1.25

6.17 ± 0.97

6.23 ± 1.06

6.16 ± 0.85

6.21 ± 1.04

0.6

Hyperuricemia, (n (%))

120 (43.0%)

103 (36.9%)

104 (37.3%)

103 (37.1%)

430 (38.6%)

0.4

eGFR <60 mL/min/1.73 m2, (n (%))

9 (3.2%)

13 (4.7%)

11 (3.9%)

7 (2.5%)

40 (3.6%)

0.6

Albumin creatinine ratio > =30 mg/g, (n (%))

57 (20.4%)

52 (18.6%)

70 (25.1%)

47 (16.9%)

226 (20.3%)

0.1

CKD, (n (%))

64 (22.9%)

62 (22.2%)

80 (28.7%)

52 (18.7%)

258 (23.1%)

0.046*