Table 2 Item description and descriptive statistics for the SF-12 component summary scores (n = 5587)*

Limitations in moderate physical activities (PF)

2.66 (0.60)

2.65-2.68

7.0

19.6

73.4

-

-

-

Limitations in climbing several flights of stairs (PF)

2.65 (0.64)

2.63-2.67

9.7

15.7

74.6

-

-

-

Accomplished less due to physical health (RP)

1.70 (0.20)

1.69-1.72

29.6

70.4

-

-

-

-

Limited in kind of work or activities due to physical health (RP)

1.72 (0.44)

1.71-1.74

27.6

72.4

-

-

-

-

Pain interference with work inside or outside home (PB)**

4.29 (0.91)

4.27-4.32

2.0

3.6

8.6

34.5

51.4

-

Health rating in general (GH)**

3.15 (1.10)

3.12-3.18

4.4

26.1

34.4

19.8

15.2

-

Interference of physical health or emotional problems with social activities (SF)

3.92 (1.08)

3.89-3.95

2.8

7.9

22.4

28.5

38.4

-

Accomplished less due to emotional problems (RE)

1.64 (0.23)

1.63-1.66

35.7

64.3

-

-

-

-

Not careful in work or activities due to emotional problems (RE)

1.67 (0.22)

1.66-1.68

32.8

67.2

-

-

-

-

Having a lot of energy (VT)**

4.04 (1.38)

4.00-4.07

4.7

9.4

22.4

19.5

28.4

15.5

Feel calm and peaceful (MH)**

4.33 (1.35)

4.29-4.36

4.1

6.6

15.8

19.5

33.3

20.6

Feel downhearted and blue (MH)

4.39 (1.57)

4.36-4.43

3.2

6.5

7.6

33.9

28.1

20.7

Summary components

PCS-12

MCS-12

Mean (SD)***

50.1 (8.5)

46.3 (10.4)

95% CI

49.8-50.3

46.1-46.6

Cronbach's α

0.73

0.72

Skewness

-0.98

-0.68

Minimum (% floor)

14.74 (0.0)

9.17 (0.0)

Maximum (% ceiling)

68.74 (0.0)

70.35 (0.0)