Musculoskeletal diseases (MD) are usually chronic, degenerative, with great social, economic and quality of life impact on patients and their family environment. They also lead to a considerable expense by health systems. However, despite their impact and significance, the extent of information on these diseases and their consequences possessed by citizens is unknown. There are few publications on the knowledge of the general population on these conditions. The results of some of these studies reflect the limited knowledge about them, especially rheumatoid arthritis (RA),1–7 something also observed in primary caregivers of women who have this disease.2

While some authors agree that both the general population3 and4 patients feel a moderate desire to know more about MD, many societal beliefs that relate to food, cold or wet weather, or osteoarthritis identified as rheumatoid arthritis, or who consider RA to be a curable disease persist.3,5,6 The lack of knowledge of the population about MD, particularly their symptoms, can cause delayed diagnosis and lead to delays in treatment, with no chance of avoiding structural damage to the joints, leading to a decreased quality of life and increased health spending.

In our environment, we found no publications on the knowledge of MD in the Spanish population. Therefore, we decided to develop this study in order to explore what Spanish people know about MD and identify subject characteristics associated with this knowledge.

After making 31289 phone calls and establishing contact in 13837 occasions the interview was conducted to 1009 subjects. Table 2 presents the description of the respondents according to sociodemographic variables. 51% of respondents were women and the most common age range was between 30 and 44 years (29.0%). The proportion of respondents was higher in the group with high school level (42.2%); those occupationally active (48.3%), among which the majority were qualified manual labor (42.8%), and residing in habitats of 10000–50000 inhabitants (24.6%).

The disease recognized by most respondents (60.3%) among the 3 most prevalent was myocardial infarction/angina, followed by cancer (60.0%) and low back pain (46.5%). Osteoarthritis and/or joint problems were recognized among the three most prevalent diseases by 35.6% of respondents and among the most disabling by 50.9%, while low back pain was recognized among the three most disabling 42, 8%. 79.2% recognized low back pain as the main cause of sick leave and 52.8% recognized osteoarthritis. In the responses to the variables related to social impact, the most recognized of the MD were related to impairment of earning capacity (91.5%) and social costs (72.1%), while 52.4% of respondents believe that MD were the most common diseases worldwide.

59.5% of the respondents knew something about MD, while 35.5% could not name any MD spontaneously. However, when asked about the list of 9 EME (Table 3), 981 persons reported having some knowledge about some of them (97.2%), although 84.5% of the respondents did not know anything about spondylitis and 87.5% knew nothing of lupus (which was not even named spontaneously). In the subgroup of 981 respondents who knew something of some MD, most recognized MD limited everyday life (93.6%), work (93.1%) and to a lesser extent, social life (73.4%) and purchasing power (64.7%) a lot or to some level. Given a list of suggested symptoms, over 90% associated joint pain, decreased mobility and joint inflammation with MD, while less than half considered them related to depression or anxiety disorders.

These same subjects answered questions on specific aspects of knowledge of MD, information that was transformed and quantified in the SK indicator. They also rated the quality of their information, most of them considering it poor or very poor (54.5%). The information available was considered as sufficient when referring to ‘what is’ the disease (71.3%), while considered only sufficient when referring to the drugs and their side effects in 37.3 and 31.6%, respectively.

According to the MD presentation in them or their families, 93.8% of respondents recognized MD due to their own condition (52.5%) and/or a relative/friend's (84.4%) (Table 4). Of these, 70% said that MD limited the daily activity of the sufferer. Asked what professional should deal with MD, most responded that they should be treated by rheumatologists (68.8%) followed by trauma specialists (21.3%).

Table 5 describes the synthetic indicators of knowledge of MD and their distribution according to sociodemographic variables. SIK level was acceptable, with 75% of the sample with a score above 0.5 over 1. The average level of knowledge is 0.62±0.16, being the indicator which obtained the highest scores regarding knowledge. GK level had an average value of 0.50±0.17 and SK was 0.18±0.10, exhibiting low values compared with other synthetic indicators of specific knowledge. The indicators were correlated with each other, with the association between GK and SK being greater (ρ=0.547). SIK had significantly higher values in men (0.64 versus 0.61 in women) and retirees (0.65). GK was higher in women (0.52), in those aged between 30 and 44 years (0.53), among the inhabitants of towns with fewer than 100000 inhabitants (0.50), those with higher educational level (0.52), and those without a professional occupation of manual laborer (>0.50). TSK was higher in women, middle-aged people with higher levels of education and non-manual occupations (P<.001 in all). The association with work status resembled the association with age, being lower for retirees (older) and students (younger).

Table 6 shows the multiple linear regression models of composite indicators. The SIK model explains about 10% of the variability of the indicator (r2=0.095). The greater the SIK was the greater is the GK and SK (maintaining this variable in the model to improve the explanatory power, even if their level of significance exceeded 0.05). It was higher in men, retirees and residents of less populated localities (maintained in the model to improve the explanatory power). It was also higher among those who considered themselves sufficiently informed as to “anything general” concerning MD, who had experience with limitations of daily life AND TO to those who have MD and, more specifically, arthritis and/or know someone that had it (kept in the model to improve the explanatory power).

The GK model explains 35.5% of its variability. GK increases with increasing SK and SIK as well as in patients with any of the 6 MD shown in Table 4, and even more so if they have had or knew someone who had had back pain, chronic back pain or arthritis. It was higher among those who were aware that MD presented a limitation for everyday life activities. However, the level of awareness was lower in men, in the most populated areas and in those who thought that the primary care physician was the one that should look after MD.

The SK model explains 42.6% of the variability. SK improved by improving GK and SIK and was greater the higher the age or educational level, whether the respondent knew someone who had a MD included in Table 3, especially if the disease was fibromyalgia, in the person or their acquaintances. SK was worse in men, retirees, when the disease was chronic back pain or if no answer was provided as to who should treat MD or if they think that it should be the trauma specialist.

This study is an approach to assess the level of knowledge of the Spanish population on MD. The information collected relates to knowledge of social and general knowledge of all the MD, specific or more prevalent MD. With this, secondary indicators were constructed on the knowledge level, quantified in 3 different planes, SIK, GK and SK, used to study its association with other variables.

According to the results, the level of knowledge of the Spanish population of the SIK in MD can be considered medium–high, the GK corresponds to an average level and the SIK to a limited level. The level of knowledge depends on the individual sociodemographic factors and personal experience with the presentation of MD, by the persons themselves or through acquaintances.

So, between sociodemographic factors, men scored higher in SIK, perhaps because this indicator inquired about labor and employment status and is a variable associated with the gender. However, most women know more on MD at the GK and SK levels, probably because, taken together, they present MD to a greater extent. Age was directly associated to a higher SK, since the probability of patients who have experienced or know someone who has experienced MD increases with age, and indirectly, SIK and SK levels were higher through the significance of the effect of being retired. A higher level of education was associated with improved SK, which is consistent with other studies4,6 and the fact that the questions that make up this indicator were accurate, not related to general education and required a degree of education or experience. Finally, living in smaller populations is associated with increased SIK and GK.

As for personal experience, the SIK and GK levels are higher among those with MD, increasing with the experience, and for those who are limited in their daily lives because of them. SK is not associated with personal experience perhaps because it is unlikely that a person is exposed to over 2 MD (almost half of respondents did not have any, and just over a fifth had more than one). Instead, SK increases by increasing the number of persons who experienced MD indirectly by knowing persons who presented them. In fact, two-thirds of respondents knew at least 2 persons who had different MD, and less than half knew of at least 3 patients with different MD.

According to the MD in question, experience, direct and indirect, of its presentation is associated differently with knowledge levels. Osteoarthritis was associated with a higher level of SIK, arthritis, low back pain and chronic back pain were associated with a higher level of GK, and fibromyalgia was associated with higher levels of SK, perhaps because the MD whose knowledge is less common is more discriminating in this indicator. Paradoxically, the experience related to chronic back pain was associated with lower levels of SK, perhaps because of the vagueness in the wording of the MD or that back pain is so prevalent that it is part of popular tradition.

Knowledge levels studied were correlated, with no collinearity, and covered different aspects with a different scope. Knowledge was vaguer, more widespread, and reaching higher scores is the SIK. In contrast, the SK, which refers to a better and more specific understanding, was less widespread and got worse scores.

Comparison with other studies is difficult because of the different designs and methodologies used in the literature. In this study, its design and methodology were determined by a different starting approach. For example, the target population is the general population, with and without MD while most studies focus on specific MD1,2,4 concrete MD or, conversely, in population free of MD.3 There are general population studies, but they are usually designed as educational interventions.5 The fundamental difference with other studies is the operational definition of “knowledge of MD” and, consequently, the nature of the results. The knowledge explored in this study refers to the socio-labor aspects and knowledge that people have of the MD epidemiological phenomenon (population) and its symptoms and consequences. Other studies, however, by addressing patients, have explored the knowledge of clinical aspects (etiology, pathophysiology, diagnosis, treatment and prophylaxis).2,3,5,7

The construction of synthetic indicators of level of knowledge, of which there is no precedent in the literature, limits the comparability of results. However, the usefulness of the indicators shows the extent to which they serve to synthesize, describe and interpret the information gathered and allow us to study the variability of the population according to them. The indicators have been constructed with a methodology that allows replication, according to the criteria of experts in MD, and satisfactorily describes the population according to the objectives. However, the variability explained by the multivariate models is limited. This suggests that the residual variability may be due to other variables not included in the models or different determinants on which information was not collected.

In short, the Spanish population has a medium level of knowledge of the importance of MD in terms of frequency and the way they affect the performance of the activities of those who have them, and identify them sufficiently, knowing their symptoms broadly, but know little about them individually. The level of knowledge varies according to sociodemographic factors and direct and indirect experience with MD presentation.

This research was funded by Abbott Foundation. The work of Juan Angel Jover and Rosario García-Vicuña was partially funded by the RETICS, RD08/0075 (RIER) research program of the Instituto de Salud Carlos III (ISCIII).

No author has a conflict of interest.