Table 1 Table 1. Subject characteristics.

Age, yrs

59.3 \(\pm\) 0.2

67.8 \(\pm\) 0.3

 < .0001

60.1 \(\pm\) 0.2

66.2 \(\pm\) 0.4

 < .0001

BMI, kg/m²

23.7 \(\pm\) 0.1

25 \(\pm\) 0.1

 < .0002

23.7 \(\pm\) 0.1

24.3 \(\pm\) 0.1

 < .0002

Waist circumference, cm

80.4 \(\pm\) 0.2

84.6 \(\pm\) 0.3

 < .0003

84.8 \(\pm\) 0.2

86.8 \(\pm\) 0.4

 < .0003

Current smoker, %

34.9 (1.2)

27.8 (1.8)

0.0014

5.1 (0.6)

3.4 (0.5)

0.0371

EtOH use, %

33.6 (1.2)

32.8 (2.1)

0.7506

2.3 (0.4)

1.5 (0.3)

0.1065

Regular exercise, %

21 (1)

20.8 (1.7)

0.9072

16.4 (0.9)

14.1 (0.9)

0.0591

Urban living, %

73.9 (2.2)

67.6 (3.2)

0.0085

77.2 (2.1)

64.8 (2.8)

 < .0001

Married, %

92.2 (0.7)

91.5 (1.2)

0.573

76.4 (1.1)

57.5 (1.4)

 < .0001

Education attainment

 < .0001

 < .0001

Elementary

28.2 (1.2)

41.3 (2)

48 (1.2)

74.2 (1.2)

Middle school

20.6 (1)

20.9 (1.7)

20.2 (0.9)

13 (0.9)

High school

32.2 (1.2)

26.6 (1.7)

24.3 (1)

10.1 (0.8)

College

19 (1)

11.2 (1.5)

7.4 (0.7)

2.8 (0.4)

Income

 < .0001

 < .0001

Q1

21.4 (1)

34.6 (2.1)

22.9 (1)

45.7 (1.3)

Q2

25.2 (1)

25.8 (1.9)

28.1 (1)

23.9 (1.1)

Q3

24.5 (1)

21.2 (1.9)

23.4 (1)

16.8 (1)

Q4

28.9 (1.1)

18.4 (1.8)

25.6 (1.1)

13.5 (0.9)

Occupation

 < .0001

 < .0001

Managerial

27.0 (1.1)

13.0 (1.4)

23.1 (1.1)

11.7 (0.9)

Non-managerial

45.8 (1.4)

49.7 (2.1)

26.1 (1.2)

27.0 (1.5)

No job

27.2 (1.1)

37.3 (2.0)

50.8 (1.1)

61.3 (1.4)

Knee pain, %

8.7 (0.6)

20.9 (1.5)

 < .0001

16.9 (0.9)

44.5 (1.3)

 < .0001

Knee stiffness, %

3.8 (0.5)

9.9 (1.2)

 < .0001

8.3 (0.6)

27.2 (1.3)

 < .0001

Radiographic spondylosis, %

22.6 (1.0)

38.8 (2.1)

 < .0001

24.4 (1.0)

46.5 (1.4)

 < .0001