Table 2.
Hazard ratios (HR) for any acute injury (AI) and severe acute injury (severe AI) incidence by most important socioeconomic, health and health behaviour variables at baseline
| Baseline variable | Category | Total number (% of experienced AI; % of experienced severe AI) | HR for AI incidence (n = 386)* | HR for AI incidence (n = 354)** | HR for severe AI incidence (≥7 service days lost) (n = 89)* | HR for severe AI incidence (≥7 service days lost) (n = 81)** |
|---|---|---|---|---|---|---|
| Socioeconomic variables | ||||||
| Age | 18–19 years | 1052 (27; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| 20–28 years | 359 (27; 6) | 1.1 (0.8–1.3) | 1.0 (0.8–1.3) | 1.1 (0.7–1.7) | 1.1 (0.7–1.8) | |
| Father's occupation | Not physical | 488 (24; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Physical | 590 (29; 7) | 1.3 (1.0–1.6) | 1.2 (1.0–1.6) | 1.0 (0.6–1.7) | 1.0 (0.6–1.6) | |
| Unclear or unemployed | 302 (28; 6) | 1.2 (0.9–1.6) | 1.1 (0.8–1.4) | 0.9 (0.5–1.6) | 0.8 (0.4–1.5) | |
| School success (educational level and grades combined) | Excellent1 | 218 (20; 4) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Good2 | 608 (28; 5) | 1.5 (1.1–2.1) | 1.5 (1.1–2.1) | 1.4 (0.6–3.0) | 1.5 (0.6–3.7) | |
| Satisfactory3 | 467 (27; 8) | 1.5 (1.1–2.1) | 1.4 (0.9–2.0) | 2.4 (1.1–5.2) | 2.5 (1.0–6.3) | |
| Poor4 | 96 (35; 13) | 2.5 (1.6–3.9) | 2.4 (1.5–3.9) | 4.5 (1.8–11.1) | 5.3 (1.9–15.1) | |
| Urbanisation level of the place of residence | Countryside | 227 (23; 5) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Town, < 10000 inhabitants | 310 (25; 8) | 1.1 (0.8–1.6) | 1.0 (0.7–1.4) | 1.5 (0.7–3.0) | 1.3 (0.6–2.5) | |
| City, ≥ 10000 inhabitants | 552 (27; 5) | 1.2 (0.9–1.7) | 1.1 (0.8–1.5) | 1.0 (0.5–2.0) | 0.9 (0.4–1.8) | |
| City, ≥ 90000 inhabitants | 298 (33; 8) | 1.5 (1.1–2.1) | 1.5 (1.1–2.2) | 1.4 (0.7–2.9) | 1.5 (0.7–3.0) | |
| Company | Anti–tank company | 263 (24; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Signal company | 540 (27; 6) | 1.3 (0.9–1.7) | 1.2 (0.9–1.7) | 0.9 (0.5–1.7) | 1.0 (0.6–2.0) | |
| Mortar company | 363 (21; 5) | 1.2 (0.9–1.7) | 1.2 (0.8–1.7) | 1.2 (0.6–2.2) | 1.4 (0.7–3.0) | |
| Engineer company | 245 (40; 9) | 1.9 (1.4–2.6) | 1.9 (1.3–2.6) | 1.5 (0.8–2.9) | 1.6 (0.8–3.2) | |
| Health variables | ||||||
| Body mass index 5 (BMI = (kg) / (m)2) | Underweight (<18.5) | 56 (21; 2) | 0.9 (0.5–1.5) | 0.9 (0.5–1.6) | 0.3 (0.1–2.4) | 0.3 (0.1–2.3) |
| Normal (18.5 − 25.0) | 812 (26; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) | |
| Pre–obese (25.0 − 30.0) | 300 (29; 7) | 1.1 (0.9–1.4) | 1.1 (0.8–1.4) | 1.2 (0.7–2.0) | 1.1 (0.6–1.8) | |
| Obese (≥30.0) | 104 (40; 12) | 1.7 (1.2–2.3) | 1.3 (0.9–1.9) | 2.0 (1.1–3.8) | 1.2 (0.6–2.4) | |
| Waist circumference (WC, cm) | Thin (<80 cm) | 271 (25; 4) | 1.0 (0.8–1.3) | 1.0 (0.8–1.4) | 0.8 (0.4–1.6) | 0.9 (0.4–1.6) |
| Average (80 – 93.5 cm) | 739 (27; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) | |
| Increased (94 – 101.5 cm) | 178 (32; 7) | 1.2 (0.9–1.7) | 1.1 (0.8–1.5) | 1.3 (0.7–2.4) | 1.0 (0.5–1.8) | |
| High (≥102 cm) | 122 (32; 11) | 1.3 (0.9–1.9) | 1.1 (0.8–1.7) | 2.2 (1.2–3.9) | 1.4 (0.7–2.7) | |
| Sum factor of musculoskeletal symptoms | Minimal symptoms6 | 440 (25; 5) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Mild symptoms7 | 548 (28; 6) | 1.2 (0.9–1.5) | 1.2 (0.9–1.5) | 1.2 (0.7–2.0) | 1.0 (0.6–1.7) | |
| Clear symptoms8 | 400 (30; 8) | 1.4 (1.0–1.8) | 1.2 (0.9–1.6) | 1.8 (1.0–3.0) | 1.3 (0.8–2.3) | |
| Chronic disease | No | 1012 (28; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Yes | 377 (26; 7) | 1.0 (0.8–1.2) | 1.0 (0.8–1.2) | 1.1 (0.7–1.8) | 1.1 (0.7–1.8) | |
| Sports injury during last month | No | 1254 (27; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Yes | 130 (29; 10) | 1.2 (0.8–1.6) | 1.2 (0.8–1.6) | 1.8 (1.0–3.3) | 2.0 (1.1–3.6) | |
| Health behaviour variables | ||||||
| Smoking habits | Never smoked regularly | 735 (25; 5) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Has smoked regularly | 650 (30; 8) | 1.3 (1.1–1.6) | 1.2 (0.9–1.6) | 1.6 (1.0–2.4) | 1.2 (0.7–1.9) | |
| Use of alcohol 9 | <3 times per week | 1148 (26; 5) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| ≥3 times per week | 240 (33; 12) | 1.3 (1.0–1.6) | 1.1 (0.8–1.4) | 2.3 (1.5–3.6) | 2.0 (1.2–3.2) | |
| Drunkenness before military service | <1 time per week | 1075 (26; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| ≥1 time per week | 313 (31; 9) | 1.3 (1.0–1.6) | 1.1 (0.8–1.4) | 1.6 (1.0–2.5) | 1.1 (0.7–1.9) | |
| Sweating exercise (Brisk leisure time sport) | ≥3 times per week | 438 (27; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| 1–2 times per week | 415 (28; 5) | 1.0 (0.8–1.3) | 1.0 (0.7–1.3) | 0.8 (0.5–1.4) | 0.7 (0.4–1.2) | |
| Only leisured exercise | 257 (27; 7) | 1.1 (0.8–1.5) | 0.9 (0.7–1.3) | 1.2 (0.7–2.2) | 0.9 (0.4–1.7) | |
| No physical exercise | 278 (27; 7) | 1.1 (0.9–1.5) | 1.0 (0.7–1.4) | 1.3 (0.7–2.3) | 0.8 (0.4–1.6) | |
| Belongs to a sports club | Yes, active member | 206 (30; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| No | 1177 (27; 6) | 0.9 (0.7–1.2) | 0.9 (0.7–1.2) | 1.1 (0.6–2.0) | 1.1 (0.6–2.1) | |
| Participates in competitive sports | Yes | 180 (31; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| No | 1206 (27; 8) | 0.9 (0.7–1.2) | 0.8 (0.6–1.1) | 0.8 (0.5–1.5) | 0.8 (0.4–1.4) | |
| Last degree in school sports | Good or excellent | 1101 (28; 6) | 1 (Referent) | 1 (Referent) | 1 (Referent) | 1 (Referent) |
| Poor or fair | 286 (24; 6) | 1.0 (0.8–1.3) | 0.9 (0.7–1.2) | 1.1 (0.7–1.9) | 0.7 (0.4–1.4) | |
Variable distribution was charted in 1411 male conscripts during the first week of military service and discharge outcomes were registered during the following 6-month military service.
Statistically significant (p< 0.05) findings are indicated with bold type.
*Adjusted for age (univariate).
**Acute: **Adjusted for age, company, smoking (previous or current smoker), frequency of drunkenness, baseline medical conditions (sum factor of earlier musculoskeletal symptoms, sports injury during the last month before entering the military), school success (educational level and grades combined), urbanisation level of the place of residence, waist circumference and physical fitness measured as a standing long jump test result.
1Attended upper secondary school, polytechnic, or university and reported excellent or good grades.
2Other subjects from upper secondary school, polytechnic, or university and conscripts from vocational school whose grades were excellent or good.
3Respondents with poorer grades in vocational school.
4Attended only comprehensive school or had permanently interrupted vocational or upper elementary school.
5Not adjusted by waist circumference since BMI and WC are strongly interconnected (χ2-test, p < 0.001).
6‘Minimal symptoms’: maximum of 7 days in one anatomical region during the last month before military entry.
7'Mild symptoms’: maximum of 7 days in 2 to 6 anatomical regions during the last month before military entry.
8'Clear symptoms’: included the remaining conscripts i.e. those with symptoms more than 8 days or more.
9Not adjusted by frequency of drunkenness since drunkenness and use of alcohol are strongly interconnected (χ2-test, p < 0.001).