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Table 1 Characteristics of the study sample according to gender and educational attainment

From: Limited educational attainment and radiographic and symptomatic knee osteoarthritis: a cross-sectional analysis using data from the Johnston County (North Carolina) Osteoarthritis Project

 

Men

(n = 1,053)

 

Women

(n = 1,574)

 

Postmenopausal Women

(n = 1,330)

 
 

Educational attainment

 

Low

High

P value

Low

High

P value

Low

High

P value

 

(n = 402)

(n = 651)

 

(n = 587)

(n = 987)

 

(n = 518)

(n = 812)

 

Demographic characteristics

         

% Age group in years

  

<0.001

  

<0.001

  

<0.001

45-54

19.7

42.9

 

17.6

44.5

 

12.2

35.3

 

55-64

23.9

32.1

 

24.2

33.2

 

25.9

38.4

 

65-74

37.8

20.7

 

35.8

15.8

 

37.8

18.6

 

75+

18.7

4.3

 

22.5

6.5

 

24.1

7.6

 

% African American

36.1

19.7

<0.001

43.6

30.6

<0.001

42.9

28.7

<0.001

Lifestyle/clinical characteristics

         

% Current Smokers

32.1

24.9

0.011

13.3

17.9

0.016

13.3

18.4

0.016

% Current alcohol use

20.4

34.1

<0.001

6.6

17.9

<0.001

6.2

17.2

<0.001

Mean BMI kg/m2 (SD)

27.6(5.0)

28.5(4.8)

0.004

30.2(6.7)

29.1(6.4)

0.001

30.0(6.5)

29.0(6.3)

0.005

% Knee injury

15.9

18.4

0.297

15.7

15.6

0.970

16.4

16.3

0.941

Occupation characteristics

         

% Physically demanding occupationa

83.3

43.0

<0.001

82.8

38.0

<0.001

82.2

37.4

<0.001

Mean occupational physical activities score (SD)b

10.7(2.6)

10.0(2.7)

<0.001

8.7(3.1)

8.8(3.0)

0.505

8.6(3.0)

8.7(3.1)

0.630

HRT use characteristics

         

% Current

HRT use

N/A

N/A

N/A

N/A

N/A

N/A

13.9

30.8

<0.001

Radiographic OA

         

% Radiographic knee OA

32.8

22.9

<0.001

41.9

23.9

<0.001

41.9

24.9

<0.001

% Bilateral radiographic knee OA

19.9

12.1

0.001

28.7

12.7

<0.001

29.2

13.7

<0.001

Symptomatic OA

         

% Symptomatic knee OA

20.2

11.1

<0.001

27.0

12.1

<0.001

27.1

13.5

<0.001

% Symptomatic bilateral knee OA

5.9

4.0

0.189

13.4

4.7

<0.001

13.1

5.0

<0.001

  1. P values are listed for comparisons between <12 years and 12+ years education within each gender category (men, women, postmenopausal women).
  2. Low educational attainment, <12 years; high educational attainment, ≥ 12 years.
  3. BMI, body mass index; HRT, hormone replacement therapy.
  4. aLaborers, fabricators, service, production, forestry, farming (as opposed to managerial, professional, technical, sales, administrative).
  5. bScale (0-16) increasing for frequency of lifting, standing, walking, and squatting.