Abstract
Background
Within the international literature, no studies have been identified that compare prevalence rates of low back pain (LBP) in chartered physiotherapists, physical and athletic therapists and those in the national working population, making it unclear whether such therapists are an occupational group at high risk of developing LBP.
Aims
To establish the prevalence of LBP among therapists (both employed and self-employed) in Ireland, to compare the employment status-, gender- and age-specific LBP prevalence rates between therapists and the national working population and to estimate the adjusted odds of developing LBP among therapists relative to the national working population.
Methods
An analysis of data from the Health In Hand Intensive Tasks and Safety (HITS) study and the third national Survey on Lifestyle, Attitudes and Nutrition (SLÁN). The HITS study was a cross-sectional study investigating work-related musculoskeletal disorders in practising therapists. The SLÁN 2007 was a face-to-face interview study of adults.
Results
LBP prevalence in therapists was 49% with no significant difference by employment status. Therapists had a much higher prevalence compared with the national working population across all demographic strata, with therapists nearly five times more likely to suffer from LBP than the national working population after careful adjustment for differences in sociodemographic factors.
Conclusions
Therapists in Ireland are an occupational group at high risk of developing LBP, warranting further research into their physical and psychosocial work-related risk factors.
Key words: Health care workers, physiotherapist, prevalence, work-related musculoskeletal disorder.
Introduction
Musculoskeletal disorders (MSDs) ‘include a wide range of inflammatory and degenerative conditions affecting the muscles, tendons, ligaments, joints, peripheral nerves and supporting blood vessels’ [1] and they affect the upper and lower limbs and the back. Within Europe, a number of occupational sectors, including health and social work, have been shown to display higher incident rates of MSDs than the national population (1.2–1.6 times higher). Interestingly, female workers in the health and social care sector reported higher than average levels of MSDs, such as backache, at 28%. This was compared with backache in female workers (22%) and in both genders (25%) across all other work sectors [2]. Although not uniquely caused by work, MSDs can be caused or aggravated by many physical and psychosocial work factors, leading to work-related MSDs (WRMSDs) [1]. It is interesting to note that recent literature has indicated that there now appears to be a decline in the incidence of WRMSDs. However, it is not clear if this decline is just ‘an artefact of changes in clinical care-seeking preferences, compensation claim reporting practices and workers’ perceptions of the role of work exposures in the onset of MSDs’ [3]. The Global Burden of Disease Study 2010 (GBD 2010) indicated that work-related low back pain (LBP) accounted for one-third of all disability arising from the occupational risk factors included in GBD 2010 [4]. Previous international research on the prevention and/or reduction of WRMSDs and symptoms, including LBP, in health care workers has focused predominantly on nurses, nursing assistants and nursing students [5,6].
It has been suggested that therapists in health care, including physiotherapists, physical therapists and athletic therapists, are an occupational group at high risk of developing LBP ‘due to the combination of prolonged stooping, repetitive low-risk and infrequent high-risk lifts’ as part of their workday tasks [7]. No investigation has been conducted to date on prevalence rates of WRMSDs/symptoms in these occupations in Ireland. Whilst internationally the terms ‘physiotherapist’ and ‘physical therapist’ are used interchangeably, in Ireland, there is a distinct difference in the use of these terms and they have been historically organized as two separate professions. Physiotherapists have been described as broad-based health care professionals who not only address musculoskeletal care of the physically active but also deal with a number of other diverse clinical fields. In contrast, physical therapists in Ireland are certified, first contact practitioners who specialize in advanced palpatory and manual techniques to assess and treat pain and discomfort in the soft tissues [8]. Finally, athletic therapists specialize in musculoskeletal injuries related to physical activity. Chartered physiotherapists, physical therapists and athletic therapists are collectively described as therapists in this paper. Whilst these professions are organized into distinct groups in Ireland, the type of work they engage in is very similar, including direct patient contact and manual/manipulative therapy, allowing them to be considered comparable occupational groups in relation to WRMSDs. Studies worldwide have investigated the 12 month prevalence of WRMSDs/symptoms in physio therapists/physical therapists with rates ranging from 92% in Korea to 32% in the USA [9,10]. Due to the differences between chartered physiotherapists, physical therapists and athletic therapists, a research study in the Irish context would be an important addition to the current literature.
Previous research has mainly focused on employed therapists and does not provide data on the large group of self-employed therapists [9–22]. Within the international literature, no studies have been identified by the authors that provide a comparison between the prevalence rate of LBP in therapists and the nationally representative working population. This investigation is essential to determine whether therapists are a high-risk occupational group for the development of LBP.
The objectives of this study were: (i) to establish the prevalence of LBP among chartered physiotherapists, physical therapists and athletic therapists, both employed and self-employed, in Ireland; (ii) to compare employment status-, gender- and age-specific LBP prevalence rates with the national working population and (iii) to estimate the adjusted odds of developing LBP in therapists in Ireland relative to the national working population.
Methods
Two separate datasets were used: the Health In Hand Intensive Tasks and Safety (HITS) study conducted in 2011 [23] and the third national Survey on Lifestyle, Attitudes and Nutrition (SLÁN) conducted in Ireland in 2007 [24].
The HITS study was a cross-sectional study investigating WRMSDs in practising chartered physiotherapists, physical therapists and athletic therapists. The sampling of physical therapists and athletic therapists was completed through three databases aiming for a representative sample from the databases of the Institute of Physical Therapy and Applied Science (IPTAS), the Irish Association of Physical Therapists (IAPT) and the Athletic Rehabilitation Therapy Certified (ARTC) organization. Chartered physiotherapists were sampled from two different populations: chartered physiotherapists in private practice and those employed in hospitals. Study participants working in private practice were randomly selected from two databases. To sample chartered physiotherapists employed in private and public hospitals, one-stage proportionate clustered sampling was used. Hospitals were selected based on bed capacity to ensure representation of physiotherapists working in different sized hospitals, reflecting approximately the proportionate distribution of different hospital sizes in Ireland. Each study participant was sent a letter inviting participation in the study, which included an information sheet, a self-administered questionnaire and a stamped addressed envelope for questionnaire return.
The HITS questionnaire was pilot tested for content validity and question clarity by therapists in all work settings. Respondents provided self-reported data on gender, age, employment status and the occurrence of LBP in the past 12 months. The question on LBP, which was part of the administered Nordic Questionnaire on MSDs [25], asked the respondent ‘Have you at any time in the last 12 months had trouble such as ache, pain, discomfort, numbness in any of the low back?’ with options to answer ‘no’, ‘left’, ‘right’ or ‘both’. For data analysis, answers of ‘left’, ‘right’ or ‘both’ were re-coded as ‘yes’. Age was recorded as a continuous variable and later re-coded into a categorical variable for data analysis. Information on respondents’ primary employment and any secondary employment was obtained to produce the employment status variable, classified into ‘employed’, ‘self-employed’ and ‘both’ for data analysis. ‘Both’ indicated individuals employed and also working part-time in their own practice.
The SLÁN 2007 was a face-to-face interview study of adults aged 18 and older, performed at the participant’s home address. SLÁN 2007 was a nationally representative survey involving 10364 respondents. The sample was deemed representative of the general population in Ireland when compared with Census 2006 figures. Complete details on the robust sampling for SLÁN 2007 can be found in the original report [24]. The overall aim of SLÁN 2007 was to provide nationally representative data on the general health, health behaviours and health service use of adults living in Ireland.
Within SLÁN 2007, participants provided self-reported data on their gender, age, usual situation in regard to work and the occurrence of LBP in the past 12 months. The usual situation in regard to work was classified into ‘employed’, ‘self-employed’ and ‘other’. Age was gathered from participants as a continuous variable and was later re-coded into a categorical variable for data analysis. The question on LBP asked respondents ‘Have you had lower back pain or other chronic back condition in the last 12 months?’ with options to answer either ‘yes’ or ‘no’.
Data were analysed using the Statistical Package for Social Science (SPSS) Version 21. Chi-squared analysis was used to determine significant differences in the prevalence of self-reported LBP with various demographic characteristics. Yates continuity correction was used in two by two tables and chi-squared test for linear trend, where appropriate. Logistic regression models were built for both samples with LBP in past 12 months as the outcome simultaneously adjusting for gender, age and employment status. Three binary logistic regression models were run: (i) a model for therapists, (ii) a model for the SLÁN 2007 national working population and (iii) a combined model for therapists and the SLÁN national working population.
Ethical approval for the HITS study was received from the Clinical Research Ethics Committee of the Cork Teaching Hospitals, Cork, Ireland. Informed consent was sought from all participants. Ethical approval for the SLÁN was provided by the Research Ethics Committee of the Royal College of Surgeons in Ireland (RCSI).
Results
The final sample size for data analysis in the HITS data was 347 therapists. This included 141 currently practising physical therapists and athletic therapists (response rate 76%), 135 chartered physiotherapists in private practice (response rate 54%) and 71 hospital-based chartered physiotherapists (response rate 31%). The overall sample size for SLÁN 2007 was 10364 respondents, a response rate of 62%. To ensure the SLÁN dataset was an appropriate comparator, only the working population of SLÁN 2007 was included in this analysis, which resulted in a final sample size for SLÁN 2007 of 5862 respondents.
Table 1 shows the demographic characteristics of therapists and the nationally representative working population sample of SLÁN 2007. A larger percentage of therapists were self-employed (46% of physiotherapists and 57% of physical and athletic therapists), compared with only 20% of the SLÁN national working population. The gender distribution within chartered physiotherapists was 77% female and 23% male, whereas within the other groupings it was practically evenly distributed between males and females. Over one-fifth of therapists were aged between 35 and 39, whereas over a quarter of the national working population within SLÁN 2007 were 50 or older.
Table 1.
Characteristics of chartered physiotherapists, physical therapists and athletic therapists and the SLÁN 2007 working population sample
| Chartered physiotherapists (n = 206) n (%) | Physical therapists and athletic therapists (n = 141) n (%) | SLÁN 2007 (n = 5862) n (%) | |
|---|---|---|---|
| Employment status | |||
| Employed | 90 (44) | 29 (21) | 4657 (79) |
| Self-employed | 94 (46) | 81 (57) | 1205 (21) |
| Both | 22 (11) | 31 (22) | – |
| Gender | |||
| Male | 48 (23) | 66 (47) | 2879 (49) |
| Female | 158 (77) | 75 (53) | 2983 (51) |
| Age group (years)a,b | |||
| ≤29 | 30 (15) | 20 (14) | 1240 (21) |
| 30–34 | 47 (23) | 21 (15) | 865 (15) |
| 35–39 | 45 (22) | 32 (23) | 824 (14) |
| 40–44 | 28 (14) | 29 (21) | 773 (13) |
| 45–49 | 18 (9) | 26 (19) | 660 (11) |
| 50+ | 37 (18) | 12 (9) | 1500 (26) |
aOne missing value for age group in chartered physiotherapists.
bOne missing value for age group in physical and athletic therapists.
Table 2 shows the prevalence of LBP among therapists and the SLÁN 2007 national working population. The overall LBP prevalence over the past 12 months was 49% (95% CI 43–54) in therapists, with very little difference by employment status. No significant differences for any of the included variables were determined within the sample populations of therapists. The LBP prevalence in the past 12 months within the national working population of SLÁN 2007 was 16% (95% CI 15–17). Self-employed individuals had a significantly higher prevalence of LBP (18%) compared with their employed counterparts (16%) (P < 0.05). The prevalence of LBP showed a linear trend with age by increasing significantly from 11% (95% CI 9–13) in individuals aged 29 or under up to 19% (95% CI 17–21) in those aged 50 or more (P < 0.001).
Table 2.
Prevalence of LBP over the past 12 months in Irish chartered physiotherapists, physical therapists and athletic therapists and the SLÁN 2007 working population sample
| Chartered physiotherapists | Physical therapists and athletic therapists | All therapists | SLÁN 2007 | |||||
|---|---|---|---|---|---|---|---|---|
| n (%) | 95% CI | n (%) | 95% CI | n (%) | 95% CI | n (%) | 95% CI | |
| Total | 206a(51) | 44–57 | 141b(46) | 38–55 | 347c(49) | 44–54 | 5862d(16) | 15–17 |
| Employment status | ||||||||
| Employed | 90 (49) | 39–59 | 26 (46) | 27–65 | 116 (48) | 39–57 | 4617 (16) | 15–17 |
| Self-employed | 94 (49) | 39–59 | 81 (48) | 37–59 | 175 (49) | 41–56 | 1199 (18) | 16–20 |
| Both | 22 (64) | 44–84 | 31 (42) | 25–60 | 53 (51) | 38–64 | – | – |
| Gender | ||||||||
| Male | 48 (40) | 26–53 | 65 (43) | 31–55 | 113 (42) | 33–51 | 2860 (16) | 14–17 |
| Female | 158 (54) | 43–62 | 73 (49) | 38–61 | 231 (52) | 46–59 | 2956 (17) | 15–18 |
| Age group (years) | ||||||||
| ≤29 | 30 (53) | 35–71 | 19 (63) | 42–85 | 49 (57) | 43–70 | 1234 (11) | 9–13 |
| 30–34 | 47 (38) | 24–52 | 20 (45) | 23–61 | 67 (40) | 29–52 | 859 (14) | 12–17 |
| 35–39 | 45 (44) | 30–59 | 31 (36) | 19–52 | 76 (41) | 30–52 | 820 (16) | 13–18 |
| 40–44 | 28 (64) | 47–82 | 29 (52) | 34–70 | 57 (58) | 45–70 | 762 (19) | 16–21 |
| 45–49 | 18 (56) | 33–79 | 26 (42) | 23–61 | 44 (48) | 34–62 | 655 (18) | 15–21 |
| 50+ | 37 (57) | 41–73 | 12 (50) | 22–78 | 49 (55) | 41–68 | 1486 (19) | 17–21 |
aOne missing value for age group in chartered physiotherapists.
bThree missing values for gender and employment status in physical and athletic therapists. Four missing values for age group in physical and athletic therapists.
cThree missing values for gender and employment status in all therapists. Five missing values for age group in all therapists.
dForty-six missing values for LBP prevalence over past 12 months in SLÁN 2007.
Table 3 shows the results of the logistic regression models. In the model for the therapists, neither gender, age, nor employment status were an independent predictor of LBP prevalence. In the model for the national working population, age group was the only independent predictor of LBP prevalence. In the combined model, the adjusted odds ratio indicates that therapists were nearly five times more likely to suffer from LBP than the national working population (adjusted odds ratio: 4.8, 95% CI 3.8–6.1, P < 0.001).
Table 3.
Logistic regression model for LBP in the past 12 months for chartered physiotherapists, physical therapists and athletic therapists, the SLÁN 2007 working population sample and the therapists and SLÁN 2007 sample combined
| Variable | Adjusted odds ratio | 95% CI | P value |
|---|---|---|---|
| All therapists (n = 347) | |||
| Employment status (reference group: employed) | |||
| Self-employed | 1.0 | 0.6–1.7 | NS |
| Both | 1.1 | 0.6–2.1 | NS |
| Gender (reference: male) | |||
| Female | 1.5 | 0.9–2.4 | NS |
| Age group (reference group: ≤29 years) | |||
| 30–34 | 0.5 | 0.2–1.1 | NS |
| 35–39 | 0.6 | 0.3–1.2 | NS |
| 40–44 | 1.1 | 0.5–2.4 | NS |
| 45–49 | 0.7 | 0.3–1.6 | NS |
| 50+ | 0.9 | 0.4–2.1 | NS |
| SLÁN 2007 (n = 5862) | |||
| Employment status (reference group: employed) | |||
| Self-employed | 1.1 | 0.9–1.3 | NS |
| Gender (reference group: male) | |||
| Female | 1.1 | 1.0–1.3 | NS |
| Age group (reference group: ≤29 years) | |||
| 30–34 | 1.3 | 1.0–1.7 | * |
| 35–39 | 1.5 | 1.1–1.9 | ** |
| 40–44 | 1.8 | 1.4–2.3 | *** |
| 45–49 | 1.7 | 1.3–2.2 | *** |
| 50+ | 1.8 | 1.5–2.3 | *** |
| All therapists and SLÁN 2007 sample (n = 6209) | |||
| Therapists (reference group: SLÁN population) | 4.8 | 3.8–6.1 | *** |
NS, not significant. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001.
Discussion
Therapists reported an overall 12 month LBP prevalence of 49% (95% CI 44–54). This prevalence is high in comparison with worldwide rates for therapists, especially European prevalence rates. Within Europe, 12 month prevalence of LBP in physiotherapists ranged from 37% in the UK to 30% in Sweden [16,17]. The national working population in Ireland reported an overall LBP prevalence of 16% (95% CI 15–17). When comparing the LBP prevalence rates for the different groups, it was clear that therapists reported a higher prevalence of LBP compared with the national working population across all demographic strata, with therapists nearly five times more likely to report suffering from LBP than the national working population after careful adjustment for differences in sociodemographic factors.
The key strengths of this study were the careful sampling method, the inclusion of self-employed workers and the comparison with the national working population. Research including self-employed workers is generally very sparse in all occupations and, to the authors’ knowledge, no research to date has investigated the LBP prevalence rates of self-employed therapists. Self-employed individuals in the national working population had a significantly higher prevalence of LBP over the past 12 months compared with their employed counterparts; however, these significant differences disappeared when adjusting for age and gender. There were no significant differences for employment status within the sample population of therapists. This may have been due to a small sample size (347) resulting in a lack of statistical power. A significant difference would have been expected as the literature indicates that self-employed workers seem to be more exposed to MSD risk factors, such as repetitive movements, carrying and moving heavy loads, prolonged standing or walking and painful and tiring positions, and are more affected by related health problems than their employed counterparts [2]. Therefore, as these differences were not found in relation to LBP, this suggests a need to investigate the prevalence of upper limb disorders in therapists to determine if the expected significant differences in employment status occur. Within the international research on LBP in therapists, only one paper compared prevalence rates in therapists with a reference group. This comparison group was limited as it included occupational therapists, an occupational group with a similarly physically demanding professional role [26]. The current paper provides a comparison with nationally representative data on the prevalence of LBP.
This paper also has some key limitations. This study was a cross-sectional one, using self-reported data. Although measured by the widely use Nordic Questionnaire, the reported prevalence estimates of LBP do not reflect medical diagnosis based on a physical examination other diagnostic measures but are based on indicative self-reported symptoms. The prevalence rates reported therefore need to be interpreted with caution due to the possibility of recall and reporting bias. However, the Nordic Questionnaire has been shown to be a useful instrument for the screening of MSDs with acceptable predictive validity along with very good construct, content and face validity when compared with medical diagnosis [27,28]. In addition, therapists are an occupational grouping with excellent awareness and knowledge on the topic of LBP, so their self-reported data may hold even stronger validity. The response rate for the physical therapists was high, making us confident that this sample was fairly representative of the population; however, in chartered physiotherapists working in hospitals it was very low at 31%; for further detail see Nolan et al. [23]. One possible contributing factor to this low response rate from hospital-based physiotherapists is the negotiations with the Irish Minister for Health in relation to the title of ‘physiotherapist’ and ‘physical therapist’, which were underway at the time of the study. With lower response rates, the possibility of selection bias needs to be taken into account. In our sample this particularly applies to hospital-based chartered physiotherapists. It is unclear if the potential systematic selection bias inflated or deflated the prevalence rates for specific groups. However, potential systematic selection bias, by gender and province of residence/professional practice, was investigated in a non-responder analysis for self-employed therapists and no systematic response bias was detected by gender or province [23]. In addition, although assessing the same outcome, there was a slight difference in the wording of the LBP prevalence question between the HITS Study and SLÁN 2007 national working population questionnaire which may have influenced the self-reports. It is also worth noting that the mode of data collection varied in the HITS Study (self-reported questionnaire) and SLÁN 2007 (face-to-face interview survey). The possible information bias due to the use of two different data collection methods may have been mitigated due to the LBP prevalence questions being unambiguous. The interpretation of unambiguous questions has been shown to be ‘relatively independent of the mode of data collection’ [29]. Finally, the difference in time periods between the SLÁN study in 2007 and the HITS Study in 2011 needs to be acknowledged. The SLÁN study was completed just prior to the global financial crisis in 2008, whereas the HITS Study was completed within the recent worldwide recession. Based on the observed declining trend in WRMSDs in recent years, it could be argued that potentially even higher estimates for therapists would have been obtained had the HITS study been conducted at the same time (2007) as the SLÁN study.
In conclusion, to the authors’ knowledge, this is the first paper to establish prevalence rates of LBP in health care therapists and compare these prevalence rates with those in a national working population. This study demonstrates a higher prevalence of reported LBP in both employed and self-employed therapists than the national working population, suggesting that this group may be involved in work practices that place them at increased risk. Further research to investigate workplace risk factors affecting this occupational group is therefore warranted, including providing targeted prevention measures and guidance on appropriate coping strategies to prevent or reduce the development of LBP.
Key points
To the authors’ knowledge, this is the first paper to compare reported low back pain prevalence rates in therapists with those in a national working population.
Irish therapists are nearly five times more likely to report suffering from low back pain than the national working population after careful adjustment for differences in age, gender and employment status.
There were no significant differences in reported low back pain prevalence for employment status in the population of therapists, suggesting a need to investigate their prevalence of upper limb disorders to determine if the expected significant differences in employment status occur.
Funding
Research grant (R&D funding, Principal Investigator: B.A.G.) from the Institution of Occupational Safety and Health (IOSH) (R1027/2).
Conflicts of interest
None declared.
Acknowledgements
The authors would like to thank all chartered physiotherapists, physical therapists and athletics therapists for their participation in the survey. We would also like to thank the professional bodies and training institutions for their cooperation and encouragement of participation in this study, including the Institute of Physical Therapy and Applied Science.
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