Characteristics of the cases with lumbar disc herniation and control subjects
| Characteristic | Case group 1 | Case group 2 | Control subjects | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lumbar disc herniation combined with osteochondrosis/spondylosis | “Pure” lumbar disc herniation (lumbar osteochondrosis/spondylosis radiographically excluded) | Population controls (including control subjects recruited by random digit dialing) | Control subjects treated with urolithiasis | |||||||||
| n | % | Mean | n | % | Mean | n | % | Mean | n | % | Mean | |
| Age at diagnosis | 43.7 | 40.0 | 43.1 | 39.7 | ||||||||
| ⩽35 years | 31 | 23.7 | 34 | 36.2 | 31 | 29.0 | 38 | 42.2 | ||||
| >35–40 years | 23 | 17.6 | 27 | 28.7 | 14 | 13.1 | 12 | 13.3 | ||||
| >40–45 years | 20 | 15.3 | 9 | 9.6 | 9 | 8.4 | 15 | 16.7 | ||||
| >45–50 years | 23 | 17.6 | 9 | 9.6 | 19 | 17.8 | 6 | 6.7 | ||||
| >50–55 years | 16 | 12.2 | 4 | 4.3 | 22 | 20.6 | 11 | 12.2 | ||||
| >55–60 years | 11 | 8.4 | 5 | 5.3 | 10 | 9.3 | 6 | 6.7 | ||||
| >60 years | 7 | 5.3 | 6 | 6.4 | 2 | 1.9 | 2 | 2.2 | ||||
| Educational level | ||||||||||||
| Graduated from high school | 28 | 21.4 | 30 | 31.9 | 42 | 39.3 | 41 | 45.6 | ||||
| Secondary school level | 39 | 29.8 | 31 | 33.0 | 30 | 28.0 | 22 | 24.4 | ||||
| Elementary level/no graduation | 63 | 48.1 | 33 | 35.1 | 35 | 32.7 | 26 | 28.9 | ||||
| Unknown | 1 | 0.8 | – | – | – | – | 1 | 1.1 | ||||
| Case identification | ||||||||||||
| Orthopaedic patients (predominantly identified retrospectively) | 47 | 35.9 | 35 | 37.2 | ||||||||
| Neurosurgical cases (identified prospectively) | 84 | 64.1 | 59 | 62.8 | ||||||||
| Region | ||||||||||||
| Frankfurt, districts with ⩾35% blue collar workers | 6 | 4.6 | – | – | 4 | 3.7 | 9 | 10.0 | ||||
| Frankfurt, districts with ⩾28–<35% blue collar workers | 20 | 15.3 | 10 | 10.6 | 22 | 20.6 | 8 | 8.9 | ||||
| Frankfurt, districts with <28% blue-collar workers | 13 | 9.9 | 15 | 16.0 | 14 | 13.1 | 12 | 13.3 | ||||
| Hanau | 23 | 17.6 | 15 | 16.0 | 11 | 10.3 | 21 | 23.3 | ||||
| Offenbach | 14 | 10.7 | 8 | 8.5 | 26 | 24.3 | 2 | 2.2 | ||||
| Bad Homburg | 8 | 6.1 | 8 | 8.5 | 6 | 5.6 | 4 | 4.4 | ||||
| Darmstadt | 29 | 22.1 | 18 | 19.1 | 6 | 5.6 | 12 | 13.3 | ||||
| Offenbach county | 12 | 9.2 | 11 | 11.7 | 18 | 16.8 | 14 | 15.6 | ||||
| Others | 5 | 3.8 | 4 | 4.3 | – | – | 8 | 8.9 | ||||
| Unknown | 1 | 0.8 | 5 | 5.3 | – | – | – | – | ||||
| Nationality | ||||||||||||
| German | 107 | 81.7 | 71 | 75.5 | 84 | 78.5 | 62 | 68.9 | ||||
| Other | 14 | 10.7 | 18 | 19.1 | 12 | 11.2 | 22 | 24.4 | ||||
| Unknown | 10 | 7.6 | 5 | 5.3 | 11 | 10.3 | 6 | 6.7 | ||||
| Diseases potentially affecting lumbar discs | ||||||||||||
| None | 71 | 54.2 | 54 | 57.4 | 84 | 78.5 | 70 | 77.8 | ||||
| Malposition of hip or pelvis, shortness of the leg, etc | 12 | 9.2 | 8 | 8.5 | 5 | 4.7 | 1 | 1.1 | ||||
| Scoliosis of lumbar spine | 38 | 29.0 | 21 | 22.3 | 12 | 11.2 | 12 | 13.3 | ||||
| Malposition of hip or pelvis etc and scoliosis | 8 | 6.1 | 8 | 8.5 | 2 | 1.9 | 2 | 2.2 | ||||
| Unknown | 2 | 1.5 | 3 | 3.2 | 4 | 3.7 | 5 | 5.6 | ||||