The aim of the study was to compare the differences in musculoskeletal health between the Polish and Spanish populations, using the ICF as a framework. Despite the potential of the ICF to provide a gold standard against which to measure different aspects of intergroup functioning, this is the first study conducted for this purpose [21].
According to our findings, there were significant differences in musculoskeletal health between the Polish and Spanish populations in all ICF entities analyzed. Regarding the different ICF domains, the main differences were found in the ICF component ‘activities and participation’. For the Polish sample, the most frequently reported ICF entity was ‘d450 Walking’ (47.7%), whereas for the Spanish sample they were ‘d430 Lifting and carrying objects’ (65.4%). The ability to walk is considered essential for most activities of daily living [22]. Typical symptoms of musculoskeletal disorders are pain, joint stiffness and reduced mobility. Pain often increases with distance covered [23]. Winter et al. showed that patients with musculoskeletal disorders have limited walking ability [24]. Jun et al. showed that people with musculoskeletal conditions often have problems with upper limb activities [25]. As activity limitations are largely dependent on the anatomical location of the musculoskeletal injury, a possible explanation for this finding is a different prevalence of such conditions between the two samples. This highlights the importance of activity assessment in clinical practice, providing clinicians with feedback on the functional problems experienced by patients on a daily basis and helping to set therapeutic goals. Regarding more general aspects of this ICF component, both populations showed a high prevalence of ICF entity ‘d240 Handling stress and other psychological demands’ (61,9% in Spain and 45.6% in Poland). Patients with musculoskeletal pain were reported to have significantly more symptoms of anxiety, depression, fatigue and insomnia. Therefore, primary care providers should consider mental health issues when treating patients with musculoskeletal conditions [26].
There were fewer differences between the samples in the ‘body functions’ component. The ICF entity 'b280 sensation of pain' was the most common ICF entity in both populations (prevalence of 78.9% in Spain and 74.2% in Poland). Other ICF entities related to movement, such as ‘b755 Involuntary movement reaction functions’ and ‘b780 Sensations related to muscles and movement functions’, were also found to be important, with small differences in prevalence between countries. The musculoskeletal system is primarily involved in locomotion, movement and the performance of physical tasks [27]. Musculoskeletal pain is a major burden and challenge for patients, families and carers because it is associated with functional limitations and loss of independence [28, 29]. It is considered the main reason for seeking health care from primary care providers [30]. Moreover, pain associated with musculoskeletal problems leads to drug dependence, suffering, social isolation and emotional distress [31]. Another finding was the high prevalence of problems related to ‘b134 Sleep functions’, which has also been liked to musculoskeletal problems in the literature [32]. Finally, ICF entities covering the functioning of other body systems also showed a similar importance, highlighting the multidimensional nature of movement [33].
With regard to the ICF component ‘environmental factors’, it was expected that the main differences between the Polish and Spanish populations would be found here. However, the most relevant ICF entity for both samples was ‘e225 Climate’ (prevalence was 58.0% in Spain and 31.8% in Poland), a remarkable finding given the marked differences in climate between the two regions. Weather parameters, including changes in temperature, humidity and pressure, are often considered risk factors for the occurrence of chronic diseases or adverse health events [34]. Changes in weather conditions are often cited by patients with musculoskeletal disorders as an important factor in triggering the onset and development of symptoms [35]. According to the review by Beukenhorst et al, 67% of studies showed an association between pain and weather variables [36]. The authors suggested that future research should consider the extent and nature of modifiable risk factors for musculoskeletal pain and strategies for managing them [36]. In general, environmental factors had a higher prevalence in Spain, but the relative importance of ICF entities was similar in both contexts.
Perhaps the greatest difficulty in conducting a cross-country study of this kind is obtaining comparable data. The ICF provides a definition of the universe of functioning and disability that allows direct comparisons of levels of functioning between groups of people. However, as each population has its own specific background, it was expected that there would be differences in socio-demographic characteristics between the samples. In our study, significant differences were found in all areas except age, which poses a challenge to comparability.
Spanish women had a higher prevalence of musculoskeletal disorders than Polish women (73.4% and 57.4%, respectively). In the data collection for this study, sex was used as a descriptive measure for the samples. This means that only biological differences between men and women were considered, while other multidimensional concepts related to the concept of gender were not taken into account [37]. Although a high prevalence in women is consistent with previous studies [38, 39], it doesn’t explain the difference found between Poland and Spain.
Another finding related to the context of the two samples was the difference in education and employment status, with the Polish population having higher levels of both. A high level of education has been associated with a protective effect on the incidence of musculoskeletal problems [40] and could explain the greater impact observed in the Spanish population on the ICF entities analyzed. In the case of employment status, its effect is controversial because, although it is recommended to stay active and return to work as soon as possible to reduce chronicity and disability related to musculoskeletal problems [41], it also implies exposure to ergonomic risk factors that may lead to injury [42].
Finally, a higher number of comorbidities was observed in the Polish sample, suggesting a lower level of general health compared to the Spanish sample. This is in line with the difference in life expectancy between the two regions. According to Eurostat, the life expectancy is 83.8 years in Castilla y León (Spain) compared to 78.5 years in Podkarpackie (Poland) [43]. Roffia et al. confirmed the importance of health care expenditure and the health care system in explaining differences in life expectancy between OECD countries [44]. Spain’s consistency in developing a health system with primary care at its core differs from Poland’s health system, which is more focused on the hospital sector and limits the development of health promotion and disease prevention activities [45, 46]. Primary health care, with its multisectoral approach to population health, can address most of the determinants of health and must therefore needs to be sufficiently developed in national health systems [47]. However, although Spain has made significant progress in general health with a strong primary care-based health system, there seems to be room for improvement in musculoskeletal health when looking at the data from Poland.
There are some limitations that should be taking into account when interpretating the findings of this study. The first is that although the data collection took place during the interaction between the physiotherapist and the patient, the Polish sample is dominated by the physiotherapist’s perspective, whereas in the Spanish case a more patient-centered perspective was used. Another limitation is the different method of calculating sample sizes for the two populations. Despite this, and given that the samples were representative of the populations analyzed, we are moderately confident that this will not bias our results. Finally, the socio-demographic data in the two samples are different, but we believe that this is inherent to this type of study and is part of the process of comparing populations from different countries.