Musculoskeletal symptoms and perceived work strain among reindeer herders in Sweden
1 Centre for Musculoskeletal Research, University of Gävle, Umeå, Sweden
2 Southern Lapland Research Department, Vilhelmina, Sweden
3 Division of Psychiatry, Department of Clinical Sciences, Umeå University, Umeå, Sweden
Correspondence to: P. Sjölander, Southern Lapland Research Department, Postgatan 7, SE-912 32 Vilhelmina, Sweden. Tel: +46 940 14494; fax: +46 940 15353; e-mail: per.sjolander{at}vilhelmina.se
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Abstract |
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Background There is a shortage of knowledge on the extent of musculoskeletal symptoms in reindeer husbandry.
Aims To investigate the prevalence and relative risk for musculoskeletal symptoms and perceived psychosocial work strain among reindeer herders.
Methods The prevalence of self-reported musculoskeletal symptoms during the last week and last year, respectively, were obtained from male reindeer herders (n = 74) of northern Sweden. Prevalence ratios (PRs) were calculated using two reference groups—women of reindeer-herding families (n = 53) and men in blue-collar occupations (n = 194). Comparisons were made of perceived job strain between the study and reference groups. Associations between job strain factors and the occurrence of musculoskeletal symptoms from different body regions were analysed with regression statistics.
Results The PRs for musculoskeletal symptoms from the hand/wrist (PR 3.48, 95% CI 1.86–6.50) and lower back (PR 1.44, 95% CI 1.06–1.95) were significantly higher among the reindeer herders in comparison with men working with other blue-collar occupations. The reindeer herders reported significantly higher work demands and decision latitude compared with both reference groups (P < 0.05). Significant associations were observed between demands and prevalence of symptoms from the lower back (OR 1.42, 95% CI 1.01–2.01) and from at least one body region (OR 1.58, 95% CI 1.07–2.32).
Conclusions The relative risk for musculoskeletal symptoms, particularly from the hands/wrists and lower back, was high among reindeer herders. It is suggested that musculoskeletal symptoms constitute a considerable health problem in modern reindeer husbandry, which calls for implementation of preventive measures addressing psychosocial, physical and socio-economic risk factors.
Keywords decision latitude; hand pain; low back pain; neck pain; reindeer husbandry; Sami; work demand
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Introduction |
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There are
2000 people in Sweden living in families where reindeer herding constitutes an important source of income [1,2]. Reindeer herding is fundamental in the Sami culture (i.e. the culture of the natives of northern Scandinavia), and the right to breed reindeer for commercial purposes is restricted to persons of Sami origin. Traditionally, reindeer herding was a nomadic way of life where the Sami families moved with their herds between grazing land in the mountains during summer and in the forests or along the fjords during winter. Today, reindeer husbandry is carried out by small family businesses in a competitive setting which has had a great impact on the reindeer-herding lifestyle and work environment. Reindeer herding has always been associated with risk factors such as high physical workload, accidents and low temperatures. Over the last 3 decades, herders have became exposed to new risk factors, largely related to extensive use of snowmobiles and other all-terrain vehicles, e.g. static and ergonomically poor body postures and vibrations. Moreover, a declining profitability in reindeer husbandry, along with increasing pressure from society to use grazing land for tourism, mining, forestry and energy production, have made reindeer-herding families more psychosocially and economically vulnerable [3–13].
In the late 1980s, it was found that reindeer herders in both Sweden and Finland showed high prevalence of musculoskeletal symptoms from the neck, shoulder and back as well as from the arms [14,15]. The relative risk for these symptoms was higher among reindeer herders who were extensively exposed to snowmobile driving [12].
In a recent prospective study on a small group of adult members of reindeer-herding families in Sweden, both men and women reported a high prevalence of musculoskeletal symptoms [16]. As in other previous studies [14,15], the prevalence was highest from the neck, shoulder, lower back, hand/wrist and knee. Interestingly, the prevalence of symptoms for neck, shoulder and lower back was higher for women than for men [16]. In another group of Swedish reindeer herders, it was recently reported that musculoskeletal symptoms from the neck, back and knees were significantly related to perceptions of poor quality of life [5].
There is a shortage of information on the occurrence of musculoskeletal symptoms among men and women of reindeer-herding families, as well as on physical, psychosocial and economical risk factors that might be associated with such symptoms in this population. So far, there has been no study where the relative risk for musculoskeletal symptoms among reindeer herders has been compared with that in other occupations.
The aim of the present study was to investigate the prevalence of musculoskeletal symptoms in different body regions, along with perceived psychosocial work strain, among reindeer-herding men.
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Methods |
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This cross-sectional postal questionnaire study was approved by the Ethical Committee, Faculty of Medicine, University of Umeå, Sweden.
The data presented in this paper emanate from a comprehensive health and work environment survey executed in collaboration with eight reindeer-herding communities (i.e. ‘samebyar’ in Swedish) between 2003 and 2006. The communities were randomly selected from the three counties in Sweden where reindeer husbandry is most common. To get a representative sample with respect to the geographical distribution of the communities, i.e. reflecting the higher density of communities in the northernmost counties, one sample was selected from the county of Jämtland, three from the county of Västerbotten and four from the county of Norrbotten. The inclusion criteria for the communities were similarities regarding number of adult community members (30–60) and number of family companies (10–30).
The survey was restricted to adult community members (age 
18 years) living in households where at least one of the males was occupied with reindeer herding throughout the year. This limitation implies that the survey embraced only those community members who were most exposed to reindeer-herding occupation and lifestyle. Out of a total of 345 community members, 154 satisfied these conditions. After receiving information about the survey, seven of the members decided not to participate. The men were used as the study group and the women as one of two control groups.
The male control group was extracted from another survey. In 2007, a self-administrated questionnaire, together with an invitation and information letter, was mailed to 2000 randomly selected adults (age 18 years), 1000 males and 1000 females, in the same geographic region as the reindeer-herding communities. Subjects, who were currently on sick leave, or held disability pensions, were excluded. From the remaining males, a subgroup of blue-collar workers was compiled. Based on description of job titles, the subjects' occupations were classified according to the Swedish standard for classification of occupations, which is based on the international standard ISCO-88. After the classification, the general population was grouped into white- and blue-collar workers. Among the blue-collar workers, those currently working full time in the building construction industry, manufacturing industries, (mostly from mining, saw mills, small mechanical enterprises and assembling industries) and the transport sector were selected as the male control group.
The questionnaire was compiled to cover a range of topics including sociodemographic conditions, musculoskeletal symptoms, psychological job strain, depression, anxiety, alcohol consumption and contact with and thoughts about suicide. For the present study, three parts of the questionnaire were used. The sociodemographic part contained information on age, level of education, employment/retirement, current occupation, marital and household data (Table 1). The second part embraced self-assessed musculoskeletal symptoms (ache, pain or discomfort) according to the Swedish version of the standardized Nordic Questionnaire [17], which includes items with dichotomized response alternatives regarding symptoms in 10 separate body regions at some point during the previous 7 days and 12 months, respectively (compare Table 2). The third part included questions on psychological job strain factors according to Karasek's demand–control model [18].
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The analyses were performed using SPSS (version 11.5, SPSS Inc., USA). The age of the study populations were normally distributed and presented as mean and standard deviation. Comparisons of average age were made by one-way ANOVA (three groups) and independent samples t-test (two groups). The frequency data on the level of education and household status were compared by chi-square test. Comparisons of the average sum scores of the job strain factors were performed with Mann–Whitney U-test.
A general log-linear model was utilized to determine the prevalence ratio (PR) of musculoskeletal symptoms, where statistical significance refers to the 95% confidence interval (CI) not including 1.0. Univariate logistic regression analyses were performed to assess associations between the psychosocial job strain factors and musculoskeletal symptoms from different body regions [presented as odds ratios (ORs) with 95% CI]. All crude associations were adjusted for household status, level of education and physical workload (compare Table 4). The physical workload was self-assessed through one of the questions in Karasek's demand–control model (‘Is your work physically heavy?’ with four response alternatives ranging from ‘never’ to ‘almost always’).
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The power was reasonably high for most of the statistically significant models, indicating sufficient size of the study and control groups. The PR models had a mean statistical power of 77% (range 58–99%) and the regression models a mean power of 89% (range 73–99%).
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Results |
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Among the reindeer-herding community members, 74 of 89 men (83%) and 53 of 58 women (91%) returned the questionnaire after two reminders (Table 1). The corresponding response rate in the male reference population was 68%. From this population, 241 blue-collar workers were identified, of whom 194 worked full time: 59 (31%) in the construction, 57 (29%) in the transport and 78 (40%) in the industry sector (Table 1).
Table 1 shows the size and the average age, together with some sociodemographic characteristics, of the study group and the two control groups. There were no differences in mean age between the reindeer-herding men and the control groups (P > 0.05). Level of education was significantly different between all three groups (P < 0.001), i.e. highest among the women of the reindeer-herding families, second highest among the blue-collar workers and lowest among the reindeer-herding men. There were no differences in household status between the reindeer-herding men and the two control groups, but there was a significantly higher frequency of cohabiting with adult and child/children and lower frequency of people living alone, among the women of the reindeer-herding families in comparison with the blue-collar workers (P < 0.05).
For most of the body regions, the prevalence of symptoms was similar among men and women of the reindeer-herding families (Table 2). However, symptoms from the head and foot/ankle regions, as well as from at least one of the 10 body regions (‘any region’ in Table 2), were more common among the women, while the prevalence of symptoms from lower and upper back were more prevalent among the men. Significant differences in PRs during the previous 7 days were found for the foot/ankle region (PR 0.39, 95% CI 0.18–0.85) and for symptoms from at least one of the 10 body regions (PR 0.85, 95% CI 0.74–0.98), as well as for symptoms from the head during the previous 12 months (PR 0.66, 95% CI 0.45–0.96).
In comparison with men working in other blue-collar occupations, the reindeer-herding men showed significantly higher PRs during the previous week for symptoms from the elbow (PR 1.94, 95% CI 1.00–3.82), hand/wrist (PR 3.48, 95% CI 1.86–6.50) and lower back (PR 1.44, 95% CI 1.06–1.95) (Table 2). Over the last year, higher PRs were observed for symptoms from the hand/wrist (PR 1.55, 95% CI 1.05–2.28) and lower back regions (PR 1.19, 95% CI 1.01–1.49), but lower ratio for symptoms from the head (PR 0.68, 95% CI 0.49–0.94).
The reindeer-herding men reported significantly higher psychological demand and decision latitude in comparison with women of the reindeer-herding families, as well as in comparison with blue-collar workers (Table 3).There were no differences in perceived intellectual discretion for the reindeer-herding men and the control groups. Small but statistically significant higher demand–control ratios were found for the reindeer-herding men in comparison with the entire group of blue-collar workers and in relation to the subgroups employed in the construction and industry sectors.
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The results of the logistic regression analyses indicated that the relations between psychosocial job strain factors and musculoskeletal symptoms were weak, both among reindeer-herding men and the two control groups (Table 4). No significant associations were found among the women of the reindeer-herding families. Except for weak associations between the demand–control ratio and symptoms from the head and lower back, there were no significant relations among the blue-collar workers (Table 4). For reindeer-herding men, statistically significant associations were found, after adjustment, between high psychological demands and high prevalence of lower back symptoms (OR 1.42, 95% CI 1.01–2.01) and of symptoms from at least one of the 10 body regions (OR 1.58, 95% CI 1.07–2.32) (Table 4). Also, a high demand–control ratio was significantly related to a high prevalence of lower back symptoms (OR 1.61, 95% CI 1.00–2.60).
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Discussion |
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We found that the prevalence and relative risk for musculoskeletal symptoms from the hand/wrist and lower back were high among reindeer herders in Sweden. Together with previous studies, our results indicate that the prevalence of musculoskeletal symptoms among reindeer herders has increased over the last couple of decades, particularly regarding symptoms from the shoulder/neck, hands/wrists and lower back. Associations between psychosocial job strain factors and musculoskeletal symptoms were weak. However, statistically significant relations were observed between high psychological demands and high prevalence of musculoskeletal symptoms from the lower back and from at least one body region. The results strengthen the conclusion that musculoskeletal pain and dysfunction constitute a considerable health problem in modern reindeer husbandry [compare 16].
The study group was small which is a potential weakness of the study. The study group was selected from the 600 male reindeer herders occupied with reindeer herding throughout the year to obtain a representative cross-sectional sample of reindeer herders.
Since none of the reindeer herders were on sick leave or had disability pension, such individuals were excluded from the control populations. The control groups probably contained a relatively larger frequency of people with generally good health and might not have been perfect representations of women of reindeer-herding families and blue-collar workers in northern Sweden which could have biased some of our results.
There were no differences in mean age between the reindeer-herding men, the reindeer-herding women and the blue-collar workers. However, there were significant differences in level of education and household status between the study and the control groups which could confound associations observed between musculoskeletal symptoms and job strain factors. To avoid this, the logistic regression models were adjusted for these possible confounders.
It was considered important to compare data from reindeer herders with geographically matched control groups. In this part of Sweden, largely due to the climate, the agriculture sector is too small to be useful as a reference occupation. However, the transport, construction and industry sectors are relatively large in northern Sweden. Modern reindeer husbandry relies on vehicle transportation of reindeers, people and equipment, both on- and off-road. Reindeer husbandry is also dependent on the reindeer herder's ability to construct and repair, e.g. fences and cottages.
Another limitation of the present study is the cross-sectional design, which does not allow any conclusions on causality between symptoms and exposures. However, the design permits identification of statistical associations that might be important.
The prevalence of musculoskeletal symptoms was similar for men and women of the reindeer-herding families. This is in contrast to previous observations which have shown higher prevalence among women than men in reindeer-herding families [16].
In comparison with the blue-collar workers, the prevalence of symptoms from the elbows, hands/wrists and lower back was increased by a factor of 1.4–3.5 among the reindeer herders. The 12-month prevalence of symptoms from the neck/shoulder and back region was higher than that reported among Swedish and Finnish reindeer herders 15–20 years ago [12,14,15]. The Finnish study reported a prevalence of 52% for neck or shoulder pain and 32% for back pain [15]. In the present study, corresponding prevalences were 57% for neck, 67% for shoulder, 43% for upper and 73% for lower back symptoms. Similar differences emerged when the present data were compared with previous Swedish data [14], indicating that the prevalence of musculoskeletal symptoms may have increased over the last decade among reindeer herders.
The 12-month prevalence of hand/arm, neck/shoulder, lower back and knee symptoms among Swedish male farmers, 40–59 years of age, was lower than among the male reindeer herders of the present study [19]. When compared to drivers of all-terrain vehicles, the reindeer-herding men showed a similar prevalence of symptoms from the neck, but considerably higher prevalences from the shoulders and the back [20]. Thus, it seems as if the reindeer herders suffered from a high prevalence of musculoskeletal symptoms, particularly from the hand/wrist and the lower back regions, in comparison with other occupations known to be associated with high frequency of symptoms.
Male reindeer herders perceived psychological demands and decision latitude as high, both in comparison with women of the reindeer-herding families and with other blue-collar workers. From the reindeer-herding populations in the county of Västerbotten, Sweden, similar gender differences regarding psychological job strain factors have been reported previously [5,6].
The demand–control ratio was relatively high among the reindeer herders. The ratio was higher than among men working in blue-collar occupations, especially those working in the manufacturing industry, but similar to that shown by the women of the reindeer-herding families and blue-collar workers in the transport sector.
It may not be that surprising that there were only weak relations between the job strain factors and the prevalence of musculoskeletal symptoms, since such symptoms can be caused and influenced by a number of factors including individual, psychosocial and physical exposure, accidents and socio-economic conditions [21–27]. However, high psychological demands were related to an increased risk for symptoms during previous 7 days from the lower back and from at least one of the 10 body regions.
There are certainly several possible underlying factors for the associations between high psychological job demands and high prevalence of musculoskeletal symptoms. In response to declining profitability, reindeer herders work more intensely, maintain larger herds and use more terrain vehicles [1]. Competition for traditional grazing lands from forestry, mining and power production might also have contributed to high psychological demand. This has forced reindeer herders to move long distances to find usable grazing grounds, particular during the winter. Most reindeer herders experience an ethnocultural obligation to carry on the traditional Sami lifestyle, based on reindeer herding, to younger generations [3,4]. Modern reindeer herders are therefore exposed to a number of psychosocial, socio-economic and sociocultural factors that might increase psychological demands as well as the risk of musculoskeletal problems.
In addition to psychosocial risk factors, the reindeer herders are exposed to a number of physical risk factors that are related to the occurrence of musculoskeletal symptoms, e.g. vibrations from terrain vehicles, low temperatures and accidents [8–10,12,13]. There is evidence that psychosocial risk factors at work are more important predictors of neck and arm symptoms when the exposure to physical risk factors is high [26]. Such working conditions seem common among reindeer-herding men. Therefore, it seems important to clarify how exposure to different physical, psychosocial, socio-economic and lifestyle factors interacts in the onset and progress of musculoskeletal symptoms among the reindeer herders.
In a recent study, it was found that the perception of physical and mental quality of life among Swedish reindeer-herding men was significantly associated with the prevalence and intensity of musculoskeletal symptoms [5]. The previous work [5], together with the high prevalence for musculoskeletal symptoms shown in the present study, suggests that musculoskeletal pain and dysfunction constitute a considerable health and quality-of-life problem in modern reindeer husbandry. This data emphasize the need to develop and implement preventive measures that reduce the prevalence of musculoskeletal symptoms among reindeer herders. Such measures should include primary preventions in the physical, psychosocial and socio-economic domains, as well as rehabilitation programmers tailored to working conditions in modern reindeer husbandry.
Key points
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County Council of Västerbotten; EU:s mål 1 Sápmi Norra Norrland; Swedish Council for Working Life and Social Research.
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None declared.
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Acknowledgements |
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The authors would like to thank Dr Margareta Barnekow-Bergkvist and Dr Albert Crenshaw for linguistic assistance and valuable comments on the manuscript.
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References |
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