Risk factors of acute and overuse musculoskeletal injuries among young conscripts: a population-based cohort study.
BACKGROUND
Military service in Finland is compulsory for all male citizens and annually about 80% of 19-year-old men enter into the service. The elevated risk for many chronic diseases and loss of function among those who are inactive and unfit can be often detected already in youth. On the other hand, activity-induced injuries among young are true public health issue. The purpose of the present prospective cohort follow-up study was to evaluate predictive associations between acute or overuse injuries and their various intrinsic risk factors.


METHODS
Four successive cohorts of conscripts who formed a representative sample of Finnish young men were followed for 6 months. At the beginning of the service, the risk factors of injuries were measured and recorded and then the acute and overuse injuries treated at the garrison clinic were identified. Predictive associations between injuries and their risk factors were examined by multivariate Cox's proportional hazard models.


RESULTS
Of the 1411 participants, 27% sustained an acute injury and 51% suffered from overuse injury. Concerning acute injuries, highest risk for severe injuries were detected among conscripts with low fitness level in both the standing long-jump and push-up tests (hazard rate, HR=5.9; 95% CI: 1.6‒21.3). A history of good degree in school sports was not a protective factor against acute injuries. High waist circumference and, on the other hand, being underweight according to BMI increased the HR for overuse injuries. Brisk leisure time physical activity before military entry was a protective factor against overuse injuries. Poor result in Cooper's test was a warning signal of elevated risk of overuse injuries.


CONCLUSIONS
We confirmed previous findings that low level of physical fitness is predictor for musculoskeletal injuries during intensive physical training. The U-shaped relationship between body composition and overuse injuries was noticed indicating that both obesity and underweight are risk factors for overuse injuries. Persons with excellent sports skills according to their earlier degrees in school sports had similar HR for acute injuries than those with poorer degrees. This indicates that school-age sports skills and fitness do not carry far and therefore preventive programmes are needed to prevent activity-induced injuries.
Research Department, Centre for Military Medicine, Lahti and Helsinki, Finland. taanila.henri.p@student.uta.fi.|Tampere Research Centre of Sports Medicine, and Injury and Osteoporosis Research Center, UKK Institute, PO Box 30, FIN-33501, Tampere, Finland. taanila.henri.p@student.uta.fi.|Research Unit of Pirkanmaa Hospital District, and Department of Orthopedics and Trauma Surgery, Tampere University Hospital, Tampere, Finland. taanila.henri.p@student.uta.fi.
Henri
H
Taanila
Tampere Research Centre of Sports Medicine, and Injury and Osteoporosis Research Center, UKK Institute, PO Box 30, FIN-33501, Tampere, Finland. jaana.h.suni@uta.fi.
Jaana H
JH
Suni
Tampere Research Centre of Sports Medicine, and Injury and Osteoporosis Research Center, UKK Institute, PO Box 30, FIN-33501, Tampere, Finland. pekka.kannus@uta.fi.|Research Unit of Pirkanmaa Hospital District, and Department of Orthopedics and Trauma Surgery, Tampere University Hospital, Tampere, Finland. pekka.kannus@uta.fi.
Pekka
P
Kannus
Division of Orthopedics and Traumatology, Seinäjoki Central Hospital, Seinäjoki, Finland. harri.pihlajamaki@uta.fi.|University of Tampere, Seinäjoki, Finland. harri.pihlajamaki@uta.fi.
Harri
H
Pihlajamäki
Research Department, Centre for Military Medicine, Lahti and Helsinki, Finland. juha-petri.ruohola@mil.fi.
Juha-Petri
JP
Ruohola
Training Division of the Defence Staff, Finnish Defense Forces, Helsinki, Finland. jarmo.viskari@mil.fi.
Jarmo
J
Viskari
Tampere Research Centre of Sports Medicine, and Injury and Osteoporosis Research Center, UKK Institute, PO Box 30, FIN-33501, Tampere, Finland. jari.parkkari@uta.fi.|Research Unit of Pirkanmaa Hospital District, and Department of Orthopedics and Trauma Surgery, Tampere University Hospital, Tampere, Finland. jari.parkkari@uta.fi.
Jari
J
Parkkari
D000208:Acute Disease; D000367:Age Factors; D001823:Body Composition; D015992:Body Mass Index; D012090:Cumulative Trauma Disorders / Q000175:diagnosis / Q000453:epidemiology*; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008297:Male; D008889:Military Personnel; D015999:Multivariate Analysis; D009140:Musculoskeletal Diseases / Q000175:diagnosis / Q000453:epidemiology*; D060051:Occupational Injuries / Q000175:diagnosis / Q000453:epidemiology*; D050177:Overweight / Q000175:diagnosis / Q000453:epidemiology; D010809:Physical Fitness; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013851:Thinness / Q000175:diagnosis / Q000453:epidemiology; D013997:Time Factors; D055105:Waist Circumference; D055815:Young Adult