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Table 3 Hazard ratios (HR) for musculoskeletal disorder (MSD) incidence and incidence of long-term MSD by health variables at baseline.

From: Aetiology and risk factors of musculoskeletal disorders in physically active conscripts: a follow-up study in the Finnish Defence Forces

Health variable

Category

Total number (% of experienced MSD;% of experienced ≥10 service days lost due to MSDs)

HR for MSD incidence (n = 652) *

HR for MSD incidence (n = 652) **

HR for long-term MSD incidence (≥10 service days lost) (n = 194) *

HR for long-term MSD incidence (≥10 service days lost) (n = 194) **

Body mass index1 (BMI = (kg)/(m)2)

Underweight (BMI < 18.5)

44 (66; 20)

1.1 (0.7-1.5)

1.1 (0.7-1.6)

1.1 (0.6-2.2)

1.1 (0.5-2.2)

 

Normal (18.5 ≤ BMI < 25.0)

539 (67; 19)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Pre-obese (25.0 ≤ BMI < 30.0)

220 (71; 19)

1.1 (0.9-1.3)

1.2 (1.0-1.5)

1.0 (0.7-1.5)

1.1 (0.7-1.6)

 

Obese (BMI ≥ 30.0)

66 (82; 33)

1.7 (1.3-2.3)

1.8 (1.3-2.4)

2.0 (1.3-3.2)

1.9 (1.2-3.2)

Waist circumference (WC, cm)

Thin (WC < 80)

177 (64; 20)

1.0 (0.8-1.2)

1.0 (0.8-1.2)

1.2 (0.8-1.8)

1.1 (0.7-1.6)

 

Normal (80 ≤ WC < 94)

499 (68; 17)

1 (Referent))

1 (Referent)

1 (Referent))

1 (Referent)

 

Increased (94 ≤ WC < 102)

126 (74; 23)

1.2 (1.0-1.5)

1.2 (1.0-1.6)

1.4 (0.9-2.1)

1.3 (0.8-2.0)

 

High (WC ≥ 102)

91 (79; 32)

1.6 (1.2-2.0)

1.7 (1.3-2.2)

2.1 (1.4-3.3)

2.2 (1.3-3.5)

Height (cm)

Shortest quartile (≤176)

184 (71; 24)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Second quartile (177-180)

248 (63; 15)

0.8 (0.7-1.0)

0.9 (0.7-1.2)

0.6 (0.4-0.9)

0.7 (0.4-1.1)

 

Third quartile (181-184)

212 (71; 20)

1.0 (0.8-1.3)

1.0 (0.8-1.3)

0.8 (0.6-1.3)

0.8 (0.5-1.2)

 

Tallest quartile (≥184)

225 (72; 21)

1.0 (0.8-1.3)

1.1 (0.9-1.4)

0.9 (0.6-1.3)

0.8 (0.5-1.3)

Self-assessed health2

Good or very good

500 (66; 17)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Average or inferior

434 (72; 24)

1.3 (1.1-1.6)

1.0 (0.9-1.3)

1.6 (1.2-2.1)

0.9 (0.7-1.3)

Sum factor of musculoskeletal symptoms

Minimal symptoms3

305 (62; 14)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Mild symptoms4

357 (68; 21)

1.2 (1.0-1.5)

1.4 (1.1-1.7)

1.7 (1.1-2.4)

1.9 (1.3-2.9)

 

Clear symptoms5

271 (78; 28)

1.8 (1.5-2.2)

1.7 (1.3-2.1)

2.4 (1.7-3.6)

2.6 (1.7-3.9)

Chronic disease

No

687 (68; 21)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Yes

247 (72; 21)

1.2 (1.0-1.4)

1.1 (0.9-1.3)

1.0 (0.8-1.4)

1.1 (0.8-1.6)

Regular medication

No

834 (69; 21)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Yes

96 (72; 18)

1.1 (0.9-1.4)

1.1 (0.8-1.4)

0.8 (0.5-1.4)

0.7 (0.4-1.3)

Orthopaedic surgery

Never

858 (68; 20)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Yes

74 (73; 27)

1.2 (0.9-1.6)

1.1 (0.8-1.6)

1.3 (0.8-2.1)

1.4 (0.9-2.4)

Chronic impairment or disability6

No

789 (67; 19)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Yes

140 (81; 31)

1.6 (1.3-2.0)

1.4 (1.1-1.7)

1.8 (1.3-2.5)

1.4 (0.9-2.1)

Sports injury during last month

No

842 (67; 20)

1 (Referent)

1 (Referent)

1 (Referent)

1 (Referent)

 

Yes

88 (82; 25)

1.4 (1.1-1.8)

1.4 (1.0-1.8)

1.3 (0.8-2.0)

1.2 (0.7-2.0)

  1. Variable distribution was charted in 944 male conscripts during the first week of military service and MSD outcomes were registered during the following six-month military service. Long-term MSD was defined as an incidence of time loss of at least 10 active service days due to one or several MSDs. Statistically significant findings are indicated with bold type.
  2. * Adjusted for age (univariate).
  3. ** Adjusted for age, company, smoking, frequency of drunkenness before military service, baseline medical conditions (sports injury during the last month before military entry, chronic impairment or disability due to prior musculoskeletal injury, earlier musculoskeletal symptoms, chronic disease), school success (educational level and grades combined), father's occupation, opinion about physical demands for a soldier, urbanisation level of the place of residence, self-assessed health, waist circumference, height, participating in individual aerobic sports, last degree achieved in school sports, belonging to a sports club, self-assessed physical fitness, participation in competitive sports and physical activity during the previous three months before entering the military.
  4. 1 Not adjusted by waist circumference since BMI and WC strongly interconnected (χ2-test, p < 0.001).
  5. 2 Compared to age-mates.
  6. 3 'Minimal symptoms': maximum seven-day lasting symptom in one anatomical region during the last month before entering the military.
  7. 4 'Mild symptoms': symptoms in two to six anatomical regions, but the symptoms had lasted a maximum of one week during the last month before military entry.
  8. 5 'Clear symptoms': included the remaining conscripts.
  9. 6 Due to prior musculoskeletal injury.