The problem of the prevalence of musculoskeletal pain (MSCs) and RSI, which the working environment can cause, is rarely discussed in the literature on rheumatology. However, this is an increasing clinical problem, and thus, rheumatologists should be made aware of it.
Studies published over 10 years old estimated that MSCs were prevalent in ~15 % of workers [19, 20]. In a later study, with 869 workers from various occupational groups (manual handlers, delivery drivers, technicians, customer services, computer operators and general office staff), the prevalence of complaints was higher. Thirty-four percent of subjects reported pain-related complaints in the neck, 35 % in the shoulders, 17 % in the elbows and 35 % in the wrists/hands . According to Walker-Bone et al.’s  questionnaire survey, almost 20 % of 6,055 persons complained of pain in the neck and in the upper limbs. According to Roquelaure et al. , over 50 % of 2,685 subjects reported MSCs. Pain-related complaints are also common in computer operators. According to Sillanpaa et al. , 63 % of them reported pain in the neck, 24 % in the shoulders, 18 % in the elbows, 35 % in the forearms and 16 % in the back. According to Bugajska et al.’s  Polish study 14–64 % of women and 13–55 % of men performing repetitive tasks reported pain in different parts of the body. Women most frequently reported complaints in all the regions of the body that were studied. Lam and Thurstone  and de Zwart et al.  confirmed those results. Our study’s results showed that the most common complaints were those in the lower back (58 % of subjects), the neck (57 %), the wrists/hands (47 %) and the upper back (44 %).
It is interesting that in measurement II, after 12 months, there were generally fewer complaints of pain in individual regions of the body; there were fewer RSIs, too. The time factor usually plays a negative role in rheumatic disorders: the patient’s condition deteriorates with time. In this case, the reverse was true. It is possible that workers whose health significantly deteriorated did not participate in measurement II. This is the so-called healthy worker effect.
MSCs are often temporary, and they are a reaction to short-term excessive musculoskeletal load. They disappear once the effort stops, so their prevalence in workers was higher than the prevalence of RSIs. According to Roquelaure et al. , over 50 % of 2,685 employees reported complaints of nonspecific MSCs, whereas 13 % of them were clinically diagnosed with at least one RSI. Similarly, in Walker-Bone et al.’s  study, only ~20 % of persons with musculoskeletal pain had clinical bases for diagnosing one of the 11 defined RSIs.
In the present study, too, RSIs diagnosed on the basis of provocation tests were less frequent than pain-related complaints. CTS, diagnosed in 33.6 % of the employees, was the most common one, followed by rotator cuff tendinitis in 15.4 %, Guyon’s canal syndrome in 13.4 %, lateral epicondylitis in 7.6 %, medial epicondylitis in 5.3 %, tendonitis of forearm–wrist extensors in 7.8 % and tendinitis of forearm–wrist flexors in 7.3 % of the subjects. We also observed statistically significant differences between women and men in prevalence of CTS and lateral epicondylitis, consequently occurred in both measurements. This finding is in line with above mentioned outcome showing that women more frequently report the musculoskeletal complains.
We are aware that the number of occurrences of MSC and RSI in our studies is high; it would certainly be lower if we had confirmed this using objective diagnostic methods. About 70 % of worker in our study performed work that was mostly physical (toolmakers, welders, seamstresses, TV assembly workers, workers assembling electric elements and packers in the cosmetic industry) and work that was a combination of both (drivers, driving instructors and nurses). In the above mentioned occupations, an increased risk of MSD might occur. Nevertheless, the results represent an actual problem faced in the occupational environment, and we claim that each case of employee musculoskeletal complaint needs observation and often modification of work performance and, possibly, even specialist consultation and treatment.
An increase in those complaints in employees performing mental work inspired researchers to look into the working environment for causes of MSCs other than physical factors. They focused on the psychosocial factors at work which, independently or in an interaction with physical factors, could be the cause. In our study, we also found the significant impact of physical factors on prevalence on MSDs (wrist/hands and upper back) and RSI (Carpal Tunnel Syndrome). Therefore, the combined effect of psychosocial and physical factors is also likely to occur and should be considered in the further analysis of our data.
Earlier literature on the subject showed a positive relationship between work-related stress and prevalence of MSDs, especially in the neck . Most studies pointed to high psychological job demands as a source of psychosocial stress in people with those complaints. There is also proof that low decision latitude, understood as workers’ influence on their work, is also responsible for pain-related complaints in the upper section of the spine. According to critics of those studies, because they are cross-sectional and not longitudinal, it is impossible to unequivocally state that those psychosocial job conditions cause MSCs. Moreover, conclusions from those studies are difficult to generalize because of the varied ways of conceptualizing psychosocial job characteristics and the tools they were measured with.
This study aimed to avoid the methodological weaknesses of previous studies. Firstly, it was longitudinal, and it was conducted twice, one year apart, each time considering symptoms in the past 12 months and in the past 7 days. The methodology of this study increases the power of the cause-and-effect predictions. Secondly, the research assumptions were based on Karasek’s conception, which is well established in the psychology of stress; it points to three basic dimensions of stress: psychological job demands, decision latitude and social support . The study also considered the authors’ latest modification of this conception, which consists in introducing another important source of stress at work into the model, i.e., job insecurity. In previous studies, on the relationship between psychosocial work characteristics and MSCs, not enough attention was devoted to this currently common threat. In the present study, job insecurity turned out to be a significant positive predictor of complaints related to the region of the elbows and wrists reported in the past 12 months and in the past 7 days. The results confirm the correctness of considering that psychosocial variable in predicting MSCs.
This study also proved that the other classic dimensions of Karasek’s model really predict the prevalence of MSCs. Psychological job demands turned out to be the strongest one. They caused a significant increase in complaints in the elbows and wrists, and ankles/feet in the past 12 months and in the elbows, wrists, ankles/feet and shoulders in the past 7 days. The importance of psychological job demands in the pathogenesis of MSDs has also been confirmed by the results that show that they significantly contribute to the development of lateral epicondylitis and medial epicondylitis. The present results related to psychological job demands thus confirm the results of other studies [12, 13].
This study also showed low decision latitude as another predictor of MSCs; the lower the decision latitude, the stronger the short- and long-term complaints in the wrists/hands, i.e., in the past 7 days and in the past 12 months. Moreover, low job decision latitude coincided with the prevalence of CTS. It should be pointed out that the present results are among the first in the literature that prove that long-term low decision latitude, understood as workers’ lack of influence over the pace of work and breaks at work, is important for the occurrence of MSCs and their developing into RSIs. This finding is in step with other studies [12, 27–32]. Social support turned out to be the weakest predictor of the complaints in the current study. Low social support at work caused an increase in complaints of pain in the region of the neck only. This is so probably because the effect of this occupational stressor is very nonspecific.
All individual (e.g., age and gender), organizational and physical variables (working hours, repetitive work, force), which are considered as inherent risk factors, were controlled in the study, and therefore, the influence of psychosocial factors on MSC’s and RSI was not contaminated by these variables.
Other researchers point to other changes that can affect the prevalence of MSCs such as style of work , excessive involvement in work  and individual abilities to cope with stress at work. Considering those parameters in future analyses would provide a promising confirmation of the recently cited in literature model of a relationship between psychosocial factors and MSCs called the “Cinderella model,” which assumes that some psychological features, such as perfectionism, can lead to overuse of low-threshold motor units in muscles [35, 36]. According to this concept, personal characteristics cause significant job demands to coincide with other demands of personal life (e.g., family ones) and thus make a good life style impossible (e.g., lack of time and motivation for physical exercise) and together they result in stress and an onset of musculoskeletal disorders. The results presented in this paper are a stimulus to conduct such holistic analyses.
In summary, psychosocial factors are a positive predictor of the prevalence of MSCs and RSIs, irrespective of personal factors (age or gender), organizational and physical factors (working hours, repetitive work, force). Thus, those factors should not be neglected by rheumatologists during their routine practice. In an analysis of the etiology of the aforementioned health problems and it should be borne in mind that apart from activity in the private life, adverse psychosocial factors at work also play a role and increase the work-related physical load. The role of prevention of MSDs at the organizational level in the workplace and pro-health behaviors of the workers themselves should not be underestimated.