Background
Methods
The Gazel cohort
The Cosali cohort
Study population
Outcome
Risk factors
Personal factors
Characteristics of KP at baseline
Occupational factors
Statistical analyses
-
Age and BMI (called model 1)
-
Age, BMI, intensity of pain, pain in other areas, self-assessed origin of KP (Gazel only), past history of knee injury (Gazel only) (called model 2)
Ethics approval
Results
Study population
Gazel | Cosali | |||
---|---|---|---|---|
Men (N = 3190) | Women (N = 950) | Men (N = 356) | Women (N = 261) | |
Duration of follow-up, in years*
| 5.99 (5.98-6.00) | 5.99 (5.98-6.00) | 3.85 (3.11-4.86) | 3.66 (2.87-4.83) |
Age, in years
| ||||
20-39 | - | - | 159 (42.3%) | 98 (37.5%) |
40-49 | - | - | 132 (35.1%) | 91 (34.9%) |
50-59 | 709 (22.2%) | 324 (34.1%) | 85 (22.6%) | 72 (27.6%) |
60-64 | 1657 (51.9%) | 420 (44.2%) | - | - |
65-69 |
824 (25.8%
)
|
206 (21.7%
)
| - | - |
BMI
| ||||
Normal weight, missing | 1074 (33.7%) |
485 (51.0%
)
|
191 (50.8%
)
|
159 (60.9%
)
|
Overweight |
1597 (50.1%
)
| 317 (33.4%) | 146 (38.8%) | 74 (28.3%) |
Obesity |
519 (16.3%
)
|
148 (15.6%
)
| 39 (10.4%) | 28 (10.7%) |
Socio-professional category
| ||||
Executives, others, missing |
541 (17.0%
)
| 111 (11.7%) | 33 (8.8%) | 12 (4.6%) |
Associate professionals or technicians |
1834 (57.5%
)
|
504 (53.0%
)
| 99 (26.3%) | 44 (16.9%) |
Employees | 160 (5.0%) | 330 (34.7%) | 26 (6.9%) |
128 (49.0%
)
|
Manual workers | 655 (20.5%) | 5 (0.5%) |
218 (58.0%
)
| 77 (29.5%) |
Carrying/Handling heavy loads**
| ||||
None | 918 (28.8%) |
667 (70.2%
)
|
162 (43.1%
)
| 149 (57.1%) |
Short or moderate exposure |
938 (29.4%
)
| 99 (10.4%) | 86 (22.9%) | 47 (18.0%) |
Long or severe exposure |
1016 (31.8%
)
| 29 (3.0%) | 89 (23.7%) | 27 (10.3%) |
Missing | 318 (10.0%) | 155 (16.3%) | 39 (10.4%) | 38 (14.6%) |
Kneeling
| ||||
None | 1082 (33.9%) |
737 (77.6%
)
| 126 (33.5%) | 105 (40.2%) |
Short or moderate exposure | 970 (30.4%) | 40 (4.2%) |
132 (35.1%
)
|
96 (36.8%
)
|
Long or severe exposure | 779 (24.4%) | 9 (0.9%) |
115 (30.6%
)
|
59 (22.6%
)
|
Missing | 359 (11.2%) | 164 (17.3%) | 3 (0.8%) | 1 (0.4%) |
Occupational change between 2002 and follow-up
| ||||
No change | 206 (54.79%) | 141 (54.02%) | ||
Change of job in the same company | 70 (18.62%) | 47 (18.01%) | ||
Change of company | 45 (11.97%) | 32 (12.26%) | ||
Inactive/ missing | 52 (14.63%) | 41 (15.71%) | ||
Walking up more than 10 flights of stairs
| ||||
None | 1883 (59.0%) | 750 (78.9%) | ||
Short exposure | 551 (17.3%) | 20 (2.1%) | ||
Long exposure | 276 (8.6%) | 8 (0.8%) | ||
Missing | 480 (15.0%) | 172 (18.1%) | ||
Intensity of pain
| ||||
Low, Missing | 1741 (54.6%) | 515 (54.2%) | 106 (28.2%) | 61 (23.4%) |
High | 1449 (45.4%) | 435 (45.8%) | 95 (25.3%) | 64 (24.5%) |
No actual pain | - | - | 175 (46.5%) | 136 (52.1%) |
Past history of knee injury
| ||||
No, missing | 1922 (60.3%) | 652 (68.6%) | ||
Yes | 1268 (39.7%) | 298 (31.4%) | ||
Self-assessed origin of knee pain
| ||||
Degenerative osteoarthritis | 1349 (42.3%) | 543 (57.2%) | ||
Other | 1559 (48.9%) | 305 (32.1%) | ||
Not completed | 282 (8.8%) | 102 (10.7%) | ||
Knee pain at baseline
| ||||
Long-lasting pain |
1310 (41.1%
)
|
490 (51.6%
)
| 124 (32.98%) | 94 (36.02%) |
Other pain | 1880 (58.9%) | 460 (48.4%) |
252 (67.02%
)
|
167 (63.98%
)
|
Pain in other areas at baseline
| ||||
No pain |
380 (11.9%
)
|
69 (7.3%
)
| 33 (8.8%) | 8 (3.1%) |
Hip pain | 740 (23.2%) | 345 (36.3%) |
110 (29.3%
)
|
107 (41.0%
)
|
Pain in other areas | 2070 (64.9%) | 536 (56.4%) | 233 (62.0%) | 146 (55.9%) |
Natural history of KP
Occupational factors associated with persistence of KP
Gazel men, N = 3190 | Cosali men, N = 376 | |||||||
---|---|---|---|---|---|---|---|---|
# | OR (95% CI) | P | P | # | OR (95% CI) | P | P | |
Age at baseline, in years
| . | . | 0.6876 | . | . | 0.4514 | ||
20-39 | 0 | - | - | 159 | 1.00 (.-.) | . | . | |
40-49 | 0 | - | - | 132 | 1.00 (0.63-1.59) | 0.9903 | . | |
50-59 | 709 | 1.00 (.-.) | . | . | 85 | 1.37 (0.81-2.34) | 0.2441 | . |
60-64 | 1657 | 1.00 (0.84-1.20) | 0.963 | . | 0 | - | - | . |
65-69 | 824 | 0.93 (0.76-1.15) | 0.514 | . | 0 | - | - | . |
BMI at baseline
| . | . |
<.0001
| . | . |
0.0428
| ||
Normal weight, missing | 1074 | 1.00 (.-.) | . | . | 191 | 1.00 (.-.) | . | . |
Overweight | 1597 |
1.34 (1.14-1.57)
|
0.0003
| . | 146 |
1.72 (1.11-2.66)
|
0.0155
| . |
Obesity | 519 |
1.67 (1.34-2.08)
|
<.0001
| . | 39 | 1.58 (0.79-3.18) | 0.1994 | . |
Socio-professional category at 35 years/at baseline
| . | . | 0.1694 | . | . |
0.0107
| ||
Executives, others, missing | 541 | 1.00 (.-.) | . | . | 33 | 1.00 (.-.) | . | . |
Associate professionals or technicians | 1834 | 1.08 (0.89-1.32) | 0.4232 | . | 99 |
3.20 (1.35-7.58)
|
0.0082
| . |
Employees | 160 | 0.89 (0.62-1.27) | 0.5227 | . | 26 |
6.00 (1.94-18.60)
|
0.0019
| . |
Manual workers | 655 | 1.24 (0.98-1.57) | 0.074 | . | 218 |
3.39 (1.51-7.63)
|
0.0032
| . |
Carrying/Handling heavy loads**
| . | . |
<.0001
| . | . | 0.0928 | ||
None, missing | 1236 | 1.00 (.-.) | . | . | 201 | 1.00 (.-.) | . | . |
Short or moderate exposure | 938 | 1.09 (0.92-1.30) | 0.3201 | . | 86 | 1.61 (0.96-2.69) | 0.0699 | . |
Long or severe exposure | 1016 |
1.51 (1.27-1.80)
|
<.0001
| . | 89 | 1.55 (0.93-2.57) | 0.0906 | . |
Carrying/Handling heavy loads**
| . | . |
0.0007
| . | . |
0.0295
| ||
No, missing | 1236 | 1.00 (.-.) | . | . | 201 | 1.00 (.-.) | . | . |
Yes | 1954 |
1.29 (1.11-1.49)
|
0.0007
| . | 175 |
1.58 (1.05-2.38)
|
0.0295
| . |
Kneeling
| . | . |
<.0001
| . | . | 0.1040 | ||
None, missing | 1441 | 1.00 (.-.) | . | . | 129 | 1.00 (.-.) | . | . |
Short or moderate exposure | 970 |
1.22 (1.03-1.44)
|
0.0202
| . | 132 | 1.51 (0.93-2.47) | 0.0963 | . |
Long or severe exposure | 779 |
1.62 (1.35-1.95)
|
<.0001
| . | 115 |
1.66 (1.00-2.76)
|
0.0494
| . |
Kneeling
| . | . |
<.0001
| . | . |
0.036
| ||
No, missing | 1441 | 1.00 (.-.) | . | . | 129 | 1.00 (.-.) | . | . |
Yes | 1749 |
1.38 (1.19-1.59)
|
<.0001
| . | 247 |
1.58 (1.03-2.43)
|
0.036
| . |
Walking up more than 10 flights of stairs
| . | . | 0.3432 | |||||
None, missing | 2363 | 1.00 (.-.) | . | . | ||||
Short exposure | 551 | 1.15 (0.95-1.39) | 0.1561 | . | ||||
Long exposure | 276 | 1.07 (0.83-1.39) | 0.5837 | . | ||||
Sick leave for depression
| . | . | 0.1616 | |||||
No | 2832 | 1.00 (.-.) | . | . | ||||
Yes | 358 | 1.18 (0.94-1.48) | 0.1616 | . | ||||
Pain intensity
| . | . |
<.0001
| . | . |
0.0004
| ||
Low, missing | 1741 | 1.00 (.-.) | . | . | 106 | 1.00 (.-.) | . | . |
High | 1449 |
1.46 (1.26-1.69)
|
<.0001
| . | 95 |
2.06 (1.15-3.69)
|
0.0154
| . |
No presentpain | 175 | 0.71 (0.44-1.15) | 0.1612 | . | ||||
Past history of knee injury
| . | . |
<.0001
| |||||
No, missing | 1922 | 1.00 (.-.) | . | . | ||||
Yes | 1268 |
1.50 (1.29-1.74)
|
<.0001
| . | ||||
Self-assessed origin of knee pain
| . | . |
<.0001
| |||||
Degenerative osteoarthritis | 1349 |
1.91 (1.64-2.23)
|
<.0001
| . | ||||
Other | 1559 | 1.00 (.-.) | . | . | ||||
Not completed | 282 | 0.80 (0.62-1.03) | 0.0871 | . | ||||
Pain in other areas at baseline
| . | . |
0.0001
| . | . | 0.7185 | ||
No pain | 380 | 1.00 (.-.) | . | . | 33 | 1.00 (.-.) | . | . |
Hip pain | 740 |
1.69 (1.31-2.18)
|
<.0001
| . | 110 | 1.37 (0.63-2.99) | 0.4262 | . |
Pain in other areas | 2070 |
1.27 (1.02-1.59)
|
0.0321
| . | 233 | 1.23 (0.59-2.55) | 0.5785 | . |
Gazel women, N = 950 | Cosali women, N = 261 | |||||||
---|---|---|---|---|---|---|---|---|
# | OR (95% CI) | P | P | # | OR (95% CI) | P | P | |
Age at baseline, in years
| 0.8944 | 0.1397 | ||||||
20-39 | 0 | - | - | 98 | 1.00 (.-.) | |||
40-49 | 0 | - | - | 91 | 1.77 (1.00-3.16) | 0.0517 | ||
50-59 | 324 | 1.00 (.-.) | 72 | 1.47 (0.80-2.71) | 0.2176 | |||
60-64 | 420 | 0.93 (0.68-1.26) | 0.638 | . | 0 | - | - | |
65-69 | 206 | 0.95 (0.66-1.38) | 0.7949 | . | 0 | - | - | |
BMI at baseline
| . |
0.0179
| . | . | 0.4198 | |||
Normal weight, missing | 485 | 1.00 (.-.) | 159 | 1.00 (.-.) | . | . | ||
Overweight | 317 |
1.40 (1.04-1.90)
|
0.028
| 74 | 1.12 (0.64-1.94) | 0.6873 | . | |
Obesity | 148 |
1.62 (1.08-2.44)
|
0.0198
| 28 | 1.73 (0.76-3.93) | 0.1896 | ||
Socio-professional category at 35 years/at baseline
| 0.4887 | 0.911 | ||||||
Executives, others, missing | 111 | 1.00 (.-.) | 12 | 1.00 (.-.) | ||||
Associates professionals or technicians | 504 | 1.24 (0.81-1.90) | 0.3314 | 44 | 1.28 (0.35-4.65) | 0.7094 | ||
Employees | 330 | 1.16 (0.74-1.81) | 0.5269 | 128 | 1.36 (0.41-4.50) | 0.6178 | ||
Manual workers | 5 | 0.39 (0.06-2.44) | 0.3145 | 77 | 1.51 (0.44-5.19) | 0.5096 | ||
Carrying/Handling heavy loads**
| 0.4154 | 0.4789 | ||||||
None, missing | 822 | 1.00 (.-.) | 187 | 1.00 (.-.) | ||||
Short or moderate exposure | 99 | 1.04 (0.66-1.62) | 0.8782 | 47 | 1.39 (0.73-2.65) | 0.3123 | ||
Long or severe exposure | 29 | 0.61 (0.29-1.28) | 0.1921 | 27 | 1.41 (0.62-3.17) | 0.4103 | ||
Carrying/Handling heavy loads**
| 0.6448 | 0.225 | ||||||
No, missing | 822 | 1.00 (.-.) | 187 | 1.00 (.-.) | ||||
Yes | 128 | 0.91 (0.62-1.35) | 0.6448 | 74 | 1.40 (0.81-2.40) | 0.225 | ||
Kneeling
| 0.8991 | 0.8211 | ||||||
None, missing | 901 | 1.00 (.-.) | 106 | 1.00 (.-.) | ||||
Short or moderate exposure | 40 | 1.18 (0.59-2.35) | 0.6446 | 96 | 0.85 (0.49-1.48) | 0.564 | ||
Long or severe exposure | 9 | 1.01 (0.25-4.06) | 0.9907 | 59 | 1.00 (0.53-1.88) | 0.9906 | ||
Kneeling
| 0.6746 | 0.6851 | ||||||
No, missing | 901 | 1.00 (.-.) | 106 | 1.00 (.-.) | ||||
Yes | 49 | 1.14 (0.61-2.13) | 0.6746 | 155 | 0.90 (0.55-1.48) | 0.6851 | ||
Carrying/Handling heavy loads * Kneeling
| 0.4537 | 0.785 | ||||||
<= short or moderate exposure, missing | 915 | 1.00 (.-.) | 187 | 1.00 (.-.) | ||||
One long or severe exposure | 32 | 0.63 (0.31-1.29) | 0.2087 | . | 62 | 1.23 (0.69-2.18) | 0.4873 | |
Both long or severe exposure | 3 | 0.99 (0.09-10.91) | 0.9904 | . | 12 | 1.08 (0.34-3.46) | 0.9000 | |
Walking up more than 10 flights of stairs
| 0.4544 | |||||||
None, missing | 922 | 1.00 (.-.) | ||||||
Short exposure | 20 | 1.50 (0.54-4.18) | 0.4331 | |||||
Long exposure | 8 | 0.50 (0.12-2.02) | 0.3316 | |||||
Sick leave for depression
| 0.7561 | |||||||
No | 576 | 1.00 (.-.) | ||||||
Yes | 374 | 0.96 (0.73-1.26) | 0.7561 | |||||
Pain intensity
|
<.0001
| . | . |
0.0057
| ||||
Low, missing | 515 | 1.00 (.-.) | 61 | 1.00 (.-.) | . | . | ||
High | 435 |
1.91 (1.44-2.52)
|
<.0001
| 64 |
2.58 (1.25-5.33)
|
0.0106
| . | |
No presentpain | 136 | 0.96 (0.53-1.77) | 0.9083 | . | ||||
Past history of knee injuries
| 0.0655 | |||||||
No, missing | 652 | 1.00 (.-.) | . | |||||
Yes | 298 | 1.32 (0.98-1.78) | 0.0655 | |||||
Self-assessed origin of knee pain
|
0.0091
| |||||||
Degenerative osteoarthritis | 543 |
1.43 (1.06-1.92)
|
0.0183
| . | ||||
Other | 305 | 1.00 (.-.) | . | . | ||||
Not completed | 102 | 0.82 (0.52-1.29) | 0.3909 | . | ||||
Pain in other areas at baseline
|
0.0012
| 0.1205 | ||||||
No pain | 69 | 1.00 (.-.) | . | 8 | 1.00 (.-.) | |||
Hip pain | 345 |
2.67 (1.58-4.52)
|
0.0003
| 107 | 0.77 (0.17-3.37) | 0.7243 | ||
Pain in other areas | 536 |
2.14 (1.29-3.55)
|
0.0032
| 146 | 0.47 (0.11-2.03) | 0.3112 |
Men | Women | |||||||
---|---|---|---|---|---|---|---|---|
Gazel, N = 3190 | Cosali, N = 376 | Gazel, N = 950 | Cosali, N = 261 | |||||
OR (95% CI) | P | OR (95% CI) | P | OR (95% CI) | P | OR (95% CI) | P | |
Model 1*
| ||||||||
Carrying/Handling heavy loads***
| 0.6212 | 0.0942 | 0.3628 | 0.1259 | ||||
No, missing | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | ||||
Yes | 1.05 (0.86-1.28) | 1.45 (0.94-2.23) | 0.83 (0.55-1.25) | 1.56 (0.88-2.76) | ||||
Kneeling
|
0.0067
|
0.0424
| 0.4817 | 0.6423 | ||||
No, missing | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | ||||
Yes |
1.31 (1.08-1.60)
|
1.62 (1.02-2.58)
| 1.26 (0.66-2.43) | 0.88 (0.52-1.49) | ||||
Model 2**
| ||||||||
Carrying/Handling heavy loads***
| 0.8665 | 0.0706 | 0.3163 | 0.1166 | ||||
No, missing | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | ||||
Yes | 1.02 (0.83-1.25) | 1.51 (0.97-2.38) | 0.81 (0.53-1.23) | 1.61 (0.89-2.91) | ||||
Kneeling
|
0.0185
|
0.0496
| 0.7488 | 0.8053 | ||||
No, missing | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | 1.00 (.-.) | ||||
Yes |
1.27 (1.04-1.56)
|
1.62 (1.00-2.63)
| 1.12 (0.57-2.18) | 0.93 (0.54-1.60) |