Date Published: March 10, 2017
Publisher: Public Library of Science
Author(s): Ville M. Mattila, Heikki Kyröläinen, Matti Santtila, Harri Pihlajamäki, Florian P Thomas.
The aim of the present study was to assess associations between physician diagnosed unspecified low back pain (LBP) during compulsory military service and self-reported LBP and physical fitness measured on average four years after military service. From a total of 1155 persons who had been pass medical examination for military service and who had completed physically demanding military training between 1997 and 2007, 778 men participated in a refresher military training course and physical tests. In this study, the association between LBP during military service and LBP in later life in addition to the association between LBP and physical fitness were examined. A total of 219 out of 778 participants (28%) had visited a physician due to some musculoskeletal symptom (ICD-10 M-diagnosis) during their military service. Seventy-four participants (9.5%) had visited a physician due to unspecified LBP during their service, and 41 (5.3%) had temporarily been absent from duty due to LBP. At the follow-up examination, 122 (15.7%) had reported LBP during the past month. LBP during military service was associated with self-reported LBP in the follow-up (p = 0.004). Of those who had been absent from duty due to LBP during their military service, 13 (31.7%) reported LBP during the past month. In risk factor analysis, no initial health behaviour and physical performance variables were associated with baseline LBP in the follow-up. The main finding of the present study was that unspecified LBP during military service predicts LBP in later life. On the basis of previous literature, it is also known that LBP is a common symptom and thus, one cannot expect to be symptomless the entire life. Interestingly, none of the health behaviours nor the physical performance studied in the follow-up were associated with baseline LBP. It appears that individuals prone to LBP have symptoms during physically demanding military service and also later in their life.
Deconditioning caused by physical inactivity has aroused concern in Western societies. Physical inactivity has been associated with several chronic diseases of which non-specific low back pain (LBP) is one of the most predominant . Low back pain is defined as pain in the lumbar or gluteal region with or without radicular pain to the lower extremities. The vast majority of individuals with pain affecting the lower back has no specific diagnosis and is categorized as having non-specific LBP , i.e. the cause of non-specific LBP is usually unknown. Non-specific LBP is common in adolescence [3–6], and the occurrence of LBP increases with age until adulthood. Moreover, there is strong evidence to suggest that adult LBP originates in adolescence . Low back disorders are the most prevalent musculoskeletal health concerns in populations and can cause varying degrees of disability . In adult populations, psychosocial difficulties [8, 9], smoking , overweight , sleep disturbances , and poor self-rated health  have been suggested to be risk factors for LBP leading to increased disability. LBP is also a very common disorder among military personnel causing disability, lost worker productivity, and increased health care costs .
In Finland, military service lasting from 6 to 12 months is compulsory for all male citizens above 18 years of age, and approximately 80% of Finnish males complete military service. The special characteristics of military training are the intensity and the volume of physical training and activities, since one of the main goals of the training is to improve the physical performance of conscripts. Because military service in Finland is compulsory, the epidemiological figures can be generalized quite well to the young adult male population.
Of the 778 participants who had completed their military service between 1997 and 2006, 219 (28%) had visited a physician due to musculoskeletal symptoms (ICD-10 M-diagnosis) during their military service. The mean duration of absence from duty was 1.2 (range 1 to 44) days. Seventy-four (9.5%) conscripts had visited a physician due to unspecified LBP during their military service, and 41 (5.3%) had temporarily been absent from duty due to LBP. The mean duration of absence from duty due to LBP per physician visit was 2.6 days (range 1 to 6).
The main finding of the present study was that unspecified LBP during military service predicts LBP in later life. An earlier study has shown that conscripts who suffer from chronic LBP before entering military service have a ten-fold higher risk of experiencing LBP during military service compared to the risk before military service . A history of suffering from LBP seems to predict a later LBP episode. Thus, young men who suffer LBP during their military service should not be directed towards occupations that require a symptomless low back without special rehabilitation and muscle fitness training. According to the findings of Suni et al., the risks for LBP can be reduced by education and muscle fitness training . They noticed that exercise and education improved the control of the lumbar neutral zone. This could have a prophylactic effect on LBP-related off-duty service days in the military environment when implemented as part of military service among young healthy men. However, more research data and knowledge are also needed to establish how physical activity and fitness associate with LBP.