Table 1 |
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Characteristics of the study sample according to gender and educational attainment |
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Men (n = 1,053) |
Women (n = 1,574) |
Postmenopausal Women (n = 1,330) |
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|
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Educational attainment |
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|
Low |
High |
P value |
Low |
High |
P value |
Low |
High |
P value |
|
|
(n = 402) |
(n = 651) |
(n = 587) |
(n = 987) |
(n = 518) |
(n = 812) |
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Demographic characteristics |
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% Age group in years |
<0.001 |
<0.001 |
<0.001 |
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|
45-54 |
19.7 |
42.9 |
17.6 |
44.5 |
12.2 |
35.3 |
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|
55-64 |
23.9 |
32.1 |
24.2 |
33.2 |
25.9 |
38.4 |
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|
65-74 |
37.8 |
20.7 |
35.8 |
15.8 |
37.8 |
18.6 |
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75+ |
18.7 |
4.3 |
22.5 |
6.5 |
24.1 |
7.6 |
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% African American |
36.1 |
19.7 |
<0.001 |
43.6 |
30.6 |
<0.001 |
42.9 |
28.7 |
<0.001 |
|
|
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Lifestyle/clinical characteristics |
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% 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 |
|
|
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Occupation characteristics |
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|
% 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 |
|
|
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HRT use characteristics |
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|
% Current HRT use |
N/A |
N/A |
N/A |
N/A |
N/A |
N/A |
13.9 |
30.8 |
<0.001 |
|
|
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Radiographic OA |
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% 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 |
|
|
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Symptomatic OA |
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|
% 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 |
|
|
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P values are listed for comparisons between <12 years and 12+ years education within each gender category (men, women, postmenopausal women). Low educational attainment, <12 years; high educational attainment, ≥ 12 years. BMI, body mass index; HRT, hormone replacement therapy. aLaborers, fabricators, service, production, forestry, farming (as opposed to managerial, professional, technical, sales, administrative). bScale (0-16) increasing for frequency of lifting, standing, walking, and squatting. |
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Callahan et al. Arthritis Research & Therapy 2010 12:R46 doi:10.1186/ar2956 |
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