Scandinavian Journal of Pain 1 (2010) 160–166

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Scandinavian Journal of Pain

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Observational studies

Predicting of pain, disability, and sick leave regarding a non-clinical sampleamong Swedish nurses

Annika Nilssona,b,∗, Per Lindbergb, Eva Denisonb,c

a Department of Caring Science and Sociology, University of Gävle, Gävle, Swedenb Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Swedenc Department of Caring and Public Health Sciences, Mälardalen University, Västerås, Sweden

a r t i c l e i n f o

Article history:Received 3 January 2010Received in revised form 21 April 2010Accepted 6 May 2010

Keywords:Registered nursesMusculoskeletal painWork-related factorsPersonal factorsSickness absenceDisability

a b s t r a c t

Objectives: Health care providers, especially registered nurses (RNs), are a professional group with a highrisk of musculoskeletal pain (MSP). This longitudinal study contributes to the literature by describingthe prevalence and change in MSP, work-related factors, personal factors, self-reported pain, disabilityand sick leave (>7 days) among RNs working in a Swedish hospital over a 3-year period. Further, resultsconcerning prediction of pain, disability and sick leave from baseline to a 3-year follow-up are reported.Method: In 2003, a convenience sample of 278 RNs (97.5% women, mean age 43 years) completed a ques-tionnaire. In 2006, 244 RNs (88% of the original sample) were located, and 200 (82%) of these completeda second questionnaire.Results: Logistic regression analyses revealed that pain, disability and sick leave at baseline best predictedpain, disability, and sick leave at follow-up. The personal factors self-rated health and sleep quality dur-ing the last week predicted pain at follow-up, while age, self-rated health, and considering yourself asoptimist or pessimist predicted disability at follow-up, however weakly. None of the work-related factorscontributed significantly to the regression solution.

Conclusions: The results support earlier studies showing that a history of pain and disability is predictiveof future pain and disability. Attention to individual factors such as personal values may be needed infurther research.

© 2010 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

DOI of refers to article:10.1016/j.sjpain.2010.05.037.∗ Corresponding author at: Department of Caring Science and Sociology, University of Gävle, Gävle, SE-801 76, Sweden. Tel.: +46 26 64 82 82; fax: +46 26 64 82 35.

E-mail address: ans@hig.se (A. Nilsson).

1877-8860/$ – see front matter © 2010 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.doi:10.1016/j.sjpain.2010.05.029

Jour

A. Nilsson et al. / Scandinavian

1. Introduction

The empirical evidence shows a variety of risk factors for devel-oping musculoskeletal pain (MSP), sick leave and disability amongthe general and working population. In several studies, the riskfactors seem to interact with each other ([1,2,35–37]). The risk fac-tors are classified differently in various studies, making it difficultto compare the constellations. The majority of the research in thefield of MSP and disability is among clinical samples, many of whichhave been cross-sectional. Prospective studies on high-risk popula-tions, such as subgroups of health care staff, are limited, especiallyprospective studies among staff not on sick leave.

In general, the main providers of practical patient care arenurses’ aides, who are frequently exposed to different physicalwork-related factors such as manual handling, heavy lifting, mov-ing or transferring patients [3]. Repeated daily physical workactivities, biomechanical strain of the back and manual handlingof objects and persons may contribute to gradual development ofpain [4,5]. These types of risk factors also concerned registerednurses (RNs) who, in addition to having administrative responsi-bility, were also responsible for assessing health care needs andprovision of medical prescriptions. The RNs is also responsible forassessing and carrying out specific nursing and a degree of coordi-nation responsibilities for other nursing tasks.

Both internationally and in Sweden, MSP have been claimed tobe the most prominent work-related problem among RNs [6–11].A review of 80 studies [12] concluded that RNs were among thosewith the most high-risk occupations with respect to low back pain(LBP). The results showed that the average point prevalence of LBPwas approximately 17%, the annual prevalence was 40–50% andthe lifetime prevalence was 35–80%. Another study [13] showedthat lifetime incidence and point prevalence of LBP were 65% and30%, respectively, among orthopaedic nurses and 58% and 25%,respectively, among intensive care nurses. A retrospective study[10] among hospital nurses showed that high levels of perceivedmental pressure, boring tasks and limited support were identifiedas risk factors for musculoskeletal complaints. With regard to mus-culoskeletal complaints, the lower back was the most commonlyreported body site (56%). MSP is not normally life threatening, butit can cause unimaginable suffering and disability.

In many cases, persons with MSP experience restrictions in theireveryday activities [33]. Work-related injuries have been shown toinfluence perceptions of injury as well as pain and disability [14].Relationships with co-workers and management may also influ-ence pain and disability [5,12,15]. One review [16] provided strongevidence that work-related factors such as monotonous work, poorrelationships at work, and low perceived ability to work were riskfactors for disabling LBP. Both MSP and disability are common diag-noses used when granting sick leave [36,17].

Health-related factors such as previous LBP have been shownto be associated with a higher risk for future sick leave amongfemale nursing aides/assistant nurses not on sick leave. In a 2-year follow-up study [18] on determinants related to health, workand social circumstances were associated with recorded sicknessabsence among hospital physicians and of female nurses the resultsshowed that all health factors were strongly associated with sick-ness absence in both groups. In another study [19] the resultsshowed that age, gender, perceived physical workload, poor gen-eral health, sciatica, worker’s own perception of his/her ability toreturn to work, and chronic complaints of LBP were associated withlonger sickness absence in workers on sick leave for 2–6 weeks due

to MSP.

It is important to define specific subgroups in working popula-tions because the risk factors vary across groups [20]. In Swedenstudies [36] has showed, that women working in the public sec-tor (especially in health care and schools) are under-represented in

nal of Pain 1 (2010) 160–166 161

studies of consequences of sick leave for back and neck pain. Therelationship between work-related factors and personality charac-teristics, on one hand, and pain, disability, and sick leave, on theother hand, among women in public health care settings (whereRNs constitute a substantial group) has thus not been well studied,especially using longitudinal designs.

The aims of the study were to (a) describe the prevalence of,as well as change over time in, MSP, work-related factors, personalfactors, pain, disability and sick leave (>7 days) among RNs workingin a Swedish hospital, and (b) predict pain, disability and sick leaveat a 3-year follow-up on the basis of work-related factors, personalfactors, pain, disability and sick leave at baseline.

2. Method

This was a longitudinal study in which a logistic regressionmodel including work and personal factors at baseline (2003), andthe dependent variables pain, disability, and sick leave at the 3-yearfollow-up (2006) were used.

2.1. Procedure

The study was conducted among RNs working in a hospital in amidsize Swedish city. The RNs were recruited from various depart-ments (n = 23; e.g., medical, surgery, obstetrics and gynaecologydepartments) at the hospital during spring 2003. The hospital direc-tor gave permission to perform the study. Nurse administrators ateach hospital department were informed about the study and thedata collection procedure. RNs were informed about the study dur-ing ward meetings and invited to participate. Those who agreed toparticipate were given a questionnaire with a personal code num-ber. A list including the names and addresses of all RNs who hadcompleted the questionnaire in 2003 was received from the hospi-tal’s chief executive secretary before the 3-year follow-up in 2006was performed. A questionnaire with the same content was mailedto the participants. Two reminders were sent out: one after 2 weeks(n = 115) and one after 4 weeks (n = 64).

2.2. Measures

Data regarding pain, disability, sick leave, work-related fac-tors, personal factors and demographic and background factorswere collected using a self-administered questionnaire standard-ised evaluation instrument of Linton et al. [21].

Further, a section was added in which RNs who reported painwere asked to answer some questions about their pain. All respon-ders were asked to report what they appreciated at their presentjobs and what they viewed as being the most difficult, boring andharmful. The subjects were asked to give a short written descrip-tion of their daily work tasks. Finally, participants were asked togive their own comments in a free format.

2.2.1. Work-related factorsFive work-related variables were measured using a 0–100 VAS.

Three items were taken from Linton et al. [21]. The question “if youtake into consideration your work routines, management, salary,promotion possibilities and work mates, how satisfied are you withyour job” was divided into two items: satisfaction with work matesand satisfaction with work leaders. The item “Is your work heavyor monotonous?” was modified to “Is your work light or heavy?”Clinical questions included perceived value of the present job and

whether work was perceived as calm or stressful.

2.2.2. Personal factorsQuestions about personal factors included age, children and

marital status. Further, subjects were asked to rate their perceived

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ealth (healthy–ill), whether they perceived themselves as opti-ist or pessimist, and to estimated physical activity on several

–100 VASs. The item assessing sleep quality during the past weekas taken from Linton et al. [21].

.2.3. Demographic and background itemsTwo items taken from Linton et al. [21] covered pain-free days

nd days using medication per week (response format 0–7 days).his section also involved background data on gender, number ofears working at the present job, present job situation, numberf children, and sick-listing during the past year. Three questionsere included at the baseline: present nursing ward, pain (yes/no),ain location (when applicable) and perceived ability to handleain. The last question was rated on a 0–100 VAS. At the 3-yearollow-up, three questions were added: “Have you changed nurs-ng ward or workplace since 2003 and, if so for what reason? Whereo you work today?”, and “If you didn’t have a pain at the baselinessessment but have one now, how long have you had it?”

.2.4. Participants who reported painParticipants who reported pain were asked to rate the follow-

ng: perceived correlation between work tasks and pain, perceivedimitations caused by pain, perceived ability to handle pain, num-er of days per week using analgesic medication, and number ofain-free days per week.

.3. Study population

In 2003, approximately 875 RNs were working in the hospitalnd being paid on a monthly basis, 794 (91.0%) of them women and1 (9.0%) of them men. A convenience sample from the entire groupas used. Of the 348 RNs asked to participate in the study, 278

80.0%) completed a questionnaire. The study group consisted of71 women (97.5%) and seven men (2.5%), and their mean age was3 years. About half of the participants reported pain, and severaleported multiple pain sites.

Two hundred and forty-four RNs (88% of the original samplen 2003) were located in 2006, of whom 200 (82%) returned the

econd questionnaire. Of those who did not participate (n = 78) 41Ns worked outside the county council in other disciplines, 1 RNetired from work and 36 RNs declined to participate.

RNs who agreed to participate there were significant differencesegarding age (t = 18.66, df = 195, p < 0.001) and years working as a

able 1aseline (2003) characteristics of the RNs (n = 278).

Variables na (

GenderFemale 271 (Male 7 (

Age 275 (

Years working as a RN 200 (

Marital statusSpouses 219 (Single 58 (

Children(Yes/no) 215/54 (Children at home (yes/no) 151/69 (

EmploymentPermanent job 267 (Nurse substitute 9 (

Working timeFull time 153 (Part time 101 (

a Information missing for some RNs at baseline.

nal of Pain 1 (2010) 160–166

RN (t = 3.46, df = 187, p < 0.001) between baseline and follow-up. Noother significant differences were found between the two assess-ments.

During the 3-year period, 62 of the RNs (31%) changed depart-ments within the hospital. Better salary, new challenges, and morevariation in their work tasks were some of the reasons given formoving to other nursing wards. Of these 62 RNs 18 (28%) explicitlymentioned stress and work environment as a reason for the change.

2.3.1. Non-respondersThere were no significant differences between responders and

non-responders (n = 78) to the follow-up (2006) questionnairesregarding age, the number of days the person had been on sickleave during the year, years working as an RN, children, maritalstatus or pain problems at the time of the baseline assessment in2003 (Table 1).

2.4. Data handling and statistical analyses

All analyses were performed using the Statistical Package forSocial Sciences (SPSS, version 14.0). Before the statistical analy-ses were performed, three new categorical variables were createdbased on the original items of the 2003 and 2006 questionnaires.(1) The number of days per week rated as free from pain wastransformed to categorical value “pain” (yes/no). (2) “Disability”was originally self-reported as perceived limitations caused by painsymptoms in leisure time, on a 0–100 VAS where a cut-off point wasset at 20 [22]. Subjects who reported a value lower than 20 werenot considered as disabled (“no”), while those scoring 21–100 werejudged as disabled (“yes”). (3) “Sick leave” was originally assessedusing a single question concerning annual total time being sick-listed. Subjects who had been sick-listed for more than 7 dayswere labelled “yes”, while RNs reporting fewer days were labelled“no”. The cut-off point is based on the general insurance systemin Sweden, where if you are ill more than 7 days, you are nor-mally expected to produce a medical certificate from the doctorin order to continue receiving sickness benefits. Wilcoxon signedrank test and dependent t-test were used to analyse differences

between baseline and the 3-year follow-up.

Prediction of pain, disability and sick leave at the 3-year follow-up based on work-related factors (value of present job, satisfactionwith work mates, satisfaction with work leaders, light–heavy work,and calm–stressful work), personal factors (age, civil status, chil-

%) m (SD) Range

98)2)

99) 43.0 (9.8) 25–64

97) 13.4 (11.2) 0.5–40

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A. Nilsson et al. / Scandinavian Journal of Pain 1 (2010) 160–166 163

Table 2Frequency and/or mean, standard deviation, and range regarding pain problems, sick days, days using medication, restriction in leisure time, pain, disability, and sick leave > 7days for the RNs (n = 200) at baseline 2003 and at the 3-year follow-up 2006.

Variables na 2003 Range na 2006 Range

(%) M (SD) (%) M (SD)

Pain problems (yes/no) 96/104 (48/52) 104/96 (52/48)Neckb,* 29 (15) 41 (21)Shouldersb 44 (22) 49 (25)Upper backb 19 (10) 23 (12)Lower backb 45 (23) 46 (23)Other pain sitesb 41 (21) 51 (26)Sick days during past year (yes/no)*** 116/84 (58/42) 5.4 (13.6) 0–121 108/92 (54/46) 16.4 (44.1) 0–354Pain during past weekb 92 (46) 3.9 (2.6) 0–7 100 (50) 4.6 (2.3) 0–7Days using medicationsb 92 (46) 1.2 (1.9) 0–7 100 (50) 0.5 (0.5) 0–7Restriction in leisure timeb,c 91 (49) 27.1 (25.1) 0–85 101 (51) 32.6 (26.6) 0–98Pain (yes/no) 81/118 (41/59) 98/102 (49/51)Disability (yes/no) 45/155 (78/23) 59/141 (71/30)Sick days (yes/no) >7days** 24/176 (1/88) 46/154 (23.77)

a Information is missing for a number of RNs at the baseline assessment and at the 3-year follows-up.b Only RNs who experienced pain answered the questions. VAS-scales generally run from 0 to 100.

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c The scales run from positive to negative.* p < 0.05.

** p < 0.1.*** p < 0.001.

ren, self-rated health, whether they perceived themselves asptimist or pessimist, sleep quality during the past week and valuef physical exercise, and pain, disability and sick leave at baselineere analysed using binary logistic regression. Separate analysesere performed for each group of predictors. Prior to the logis-

ic regression analyses, Spearman’s rho correlation coefficient (r)as used to study bivariate relationships between the outcome

nd predictor variables as well as among the predictor variables.ulticollinearity (values of r > 0.9) [22] was not present in the data.issing data (<10%) [38] were not substituted. Thus, the sample

ize varies across the different analyses. The results are presented asdds ratios with 95% confidence intervals. The level of significanceas set at 5% for all statistical tests.

.5. Ethical considerations

The study was approved by the Ethics Committee at the Med-cal Faculty, Uppsala University (reference number 02-314). RNs

ho were asked to participate in the study were informed thatheir participation was voluntary and that confidentiality would bessured.

able 3ean (m), standard deviation (SD), and range for work-related factors and personal facto

Variables 2003

na m (SD)

Work-related variablesCorrelation: symptom–work–taskb,c 91 46.7 (27.1)Value of present jobd 195 75.5 (20.0)Satisfaction with workmatesd 195 86.1 (18.3)Satisfaction with work leadersd 193 71.2 (24.2)Work: light–heavyc 193 56.4 (24.2)Work: calm–stressfulc 195 67.0 (20.1)Personal factorsAbility to handle painb,c 92 21.7 (20.2)Healthy–illc 198 14.2 (15.0)Optimist–pessimistc 196 18.5 (17.9)Sleep quality during the past weekc 198 28.6 (25.9)Value of physical exercised 198 68.7 (25.1)

a Information missing for a number of RNs at the baseline assessment and at the 3-yeab Only RNs who experienced pain answered the questions. VAS-scales generally run froc The scales run from positive to negative.d The scales run from negative to positive.

*** p < 0.001.

3. Results

3.1. Group characteristics and differences

Table 2 shows descriptive statistics and differences in pain prob-lems, pain sites, sick days and restriction in leisure time among the200 RNs responding at baseline and follow-up. Ninety-six subjectsreported pain problems at baseline and 104 at the 3-year follow-up.The most commonly reported pain sites at baseline were lower backand shoulder pain. “Other pain sites” and shoulder pain were themost commonly reported at the 3-year follow-up. Problems withneck pain increased significantly at the 3-year follow-up (z = −2.12,p = 0.034) as compared to baseline. The mean number of sick days(t = 3.40, df = 199, p < 0.001) and sick days >7 (z = −2.89, p = 0.004)during the past year were significantly higher at the 3-year follow-up compared to baseline.

Table 3 shows work-related factors and personal factors for the

200 RNs responding at baseline and follow-up. For the work-relatedfactors, satisfaction with work leaders decreased significantly(t = −3.50, df = 188, p < 0.001) at the 3-year follow-up as comparedto baseline. Perceived value of physical exercise increased sig-

rs at baseline 2003 and at the 3-year follow-up 2006 (n = 200).

Range 2006 Range

na m (SD)

0–98 102 44.1 (32.1) 0–1006–100 196 78.0 (16.4) 9–1006–100 198 84.3 (15.2) 16–1002–100 198 64.1*** (24.0) 3–1003–100 198 57.2 (25.2) 3–1005–100 198 68.8 (18.9) 8–98

0–92 100 19.0 (16.6) 0–750–90 197 16.2 (15.5) 0–820–80 197 18.9 (18.5) 0–880–100 197 29.8 (26.0) 0–991–100 194 74.3*** (22.5) 2–98

r follows-up.m 0 to 100.

164 A. Nilsson et al. / Scandinavian Jour

Table 4Spearman rank correlations (rs) between the outcome variables pain, disability, andsick leave (1–3) at follow-up 2006 and predictors related to work (4–8) and personalfactors (9–15) at baseline 2003.

Variables Pain Disability Sick leave

1. Pain –2. Disability 0.64**

3. Sick leave > 7 days 0.10 0.20*

4. Value of present job 0.01 −0.07 −0.15*

5. Satisfaction of workmates 0.05 −0.04 −0.18*

6. Satisfaction of work leaders 0.02 −0.01 −0.107. Work: light–heavy 0.03 −0.07 0.018. Work: calm–stressful 0.02 −0.07 −0.009. Age 0.10 0.24** 0.0010. Spouses/single 0.10 −0.01 0.0311.Children 0.16* 0.09 −0.0112. I am: healthy–ill 0.23** 0.27** 0.16*

13. I am: optimist–pessimist 0.09 0.00 −0.0314. Sleep quality during the past week 0.24** 0.22** 0.0515. Value of physical exercise 0.01 −0.06 −0.11

n = 200 for variables 1, 2, 3, 9 and 10; n = 198 for variables 12, 14 and 15; n = 196 forvariable 13; n = 195 for variables 4, 5, 8 and 11; n = 193 for variables 6 and 7.

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square = 3.75, df = 5, p = 0.586). The prediction of disability based onpersonal factors was analysed in a total of 192 cases (n = 135 with

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* p < 0.05.** p < 0.01.

ificantly (t = 3.56, df = 191, p < 0.001) at the 3-year follow-up asompared to baseline.

RNs reported what they experienced as being most difficult, bor-ng and harmful at their present jobs. Several reported both physical

ork factors and stress as most harmful. Thirty-nine RNs explic-tly pointed out physical work factors (e.g., heavy lifts) at baseline,

hile 74 pointed out stress. At the 3-year follow-up, the corre-ponding figures were 33 and 63, respectively.

.2. Prediction of pain, disability and sick leave

Logistic regression analyses were performed with pain, disabil-ty and sick leave as outcomes at the 3-year follow-up (2006) and

ork-related factors, personal factors, and pain, disability and sick

eave as predictor variables at baseline (2003). The results of theegression analyses in table five give coefficients, odds ratios andonfidence intervals (CI) for each predictor variable in the models.

able 5eta coefficient (B), odds ratio (OR), and confidence interval (CI) for the prediction of paain, disability and sick leave at baseline 2003 (n = 200).

Predictors Pain

B OR (95%CI)

Work-related factors n = 191Value of present job −0.03 1.00 (0.98, 1.02)Satisfaction of workmates 0.00 1.00 (0.98, 1.02)Satisfaction of work leaders 0.00 1.00 (0.99, 1.02)Work: light–heavy −0.00 1.00 (0.98, 1.01)Work: calm–stressful 0.00 1.00 (0.99, 1.03)Personal factors n = 192Age 0.01 1.00 (0.98, 1.05)Spouses/single 0.29 1.33 (0.57, 3.11)Children 0.51 1.66 (0.65, 4.23)Healthy–ill 0.03 1.04 (1.01, 1.06)Optimist–pessimist −0.00 1.00 (0.98, 1.02)Sleep quality the past week 0.01 1.01 (1.00, 1.03)Value of physical exercise 0.00 1.00 (0.99, 1.01)

n = 199Pain at baseline 1.88 6.56 (2.97, 14.48)Disability at baseline 0.50 1.65 (0.61, 4.44)Sick leave at baseline −0.10 0.91 (0.34, 2.41)

old figures, significant values; pain, healthy–ill and sleep quality during the past week: pptimist–pessimist, pain at baseline, disability at baseline: p < 0.01, healthy–ill: p < 0.001;

nal of Pain 1 (2010) 160–166

3.3. Bivariate correlations—outcome variables and predictorvariables

Table 4 shows Spearman’s correlations test (rs) of the outcomevariables pain, disability and sick leave at the 3-year follow-up andpredictor variables at baseline. There was a significant correlationbetween pain and disability (rs = 0.64, n = 200, p < 0.01). Correlationsbetween the independents variables were weak to moderate, therange of significant correlations being rs = −0.15 to rs = 0.64.

3.4. Pain

The prediction of pain based on work-related factors was anal-ysed in a total of 191 cases (n = 99 with no pain, n = 92 with pain). Thefull model was not significant (chi-square = 0.27, df = 5, p = 0.998).The prediction of pain based on personal factors was analysed ina total of 192 cases (n = 99 with no pain, n = 93 with pain). Thefull model significantly predicted pain (chi-square = 25.18, df = 7,p < 0.001). Self-rated health and sleep quality during the past weeksignificantly predicted pain as single items in the model. Forhealthy, the OR was 1.04, which means that the odds of being inthe pain group increased by 4% with a one-unit increase in this vari-able. For sleep quality during the past week, the OR was 1.01, thusreflecting an increase of only 1%. The prediction of pain based onpain, disability and sick leave at baseline was analysed in a total of199 cases (n = 101 with no pain, n = 98 with pain). The full model sig-nificantly predicted pain (chi-square = 47.56, df = 3, p < 0.001). Painat baseline predicted pain at follow-up as a single item in the model.The OR was 6.56, which means that being in the pain group at base-line increased the odds of being in the pain group at follow-up by6.56 times (see Table 5).

3.5. Disability

The prediction of disability based on work-related factorswas analysed in a total of 191 cases (n = 134 with no disability,n = 57 with disability). The full model was not significant (chi-

no disability, n = 57 with disability). The full model significantlypredicted disability (chi-square = 41.91, df = 7, p < 0.001). Age, self-rated health and considering yourself as optimist or pessimist

in, disability and sick leave at follow-up by work-related and personal factors and

Disability Sick leave

B OR (95%CI) B OR (95%CI)

n = 191 n = 191−0.01 0.99 (0.97, 1.01) −0.01 0.99 (0.97, 1.01)

0.00 1.00 (0.98, 1.02) −0.03 0.97 (0.95, 1.00)0.00 1.00 (0.99, 1.02) 0.01 1.01 (0.99, 1.03)

−0.01 0.99 (0.98, 1.01) 0.01 1.01 (0.99, 1.03)0.00 1.00 (0.98, 1.03) 0.01 1.01 (0.98, 1.03)

n = 192 n = 1920.07 1.07 (1.02, 1.12) −0.00 1.00 (0.96, 1.04)

−0.12 0.80 (0.35, 2.26) 0.10 1.10 (0.42, 2.88)−0.34 0.71 (0.24, 2.16) −0.10 0.94 (0.33, 2.65)

0.05 1.06 (1.02, 1.09) 0.04 1.04 (1.01, 1.06)−0.03 0.96 (0.95, 1.00) −0.02 0.99 (0.96, 1.01)

0.02 1.02 (1.00, 1.03) −0.01 1.00 (0.98, 1.01)−0.00 1.00 (0.99, 1.02) −0.01 0.99 (0.98, 1.01)

n = 199 n = 1991.17 3.23 (1.42, 7.32) −0.22 0.81 (0.31, 2.08)1.17 3.21 (1.33, 7.70) 1.30 3.67 (1.34, 0.05)1.13 3.08 (1.17, 8.13) 0.63 1.88 (0.73, 4.88)

< 0.05, pain at baseline: p < 0.001; disability, sick leave at baseline: p < 0.05, age andSick leave, disability at baseline: p < 0.05.

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ignificantly predicted disability at follow-up as single items in theodel. For age the OR was 1.07, which means that an increase in

ge by 1 year is associated with a 7% increase in the odds of being inhe disabled group. For healthy-self-rated health, the OR was 1.06,hich means that the odds of being in the disabled group increased

y 6%. For optimist–pessimist, the OR was 0.96, which means thathe odds of being in the disabled group decreased by 4% with a one-nit increase in this variable. The prediction of disability based onain, disability and sick leave at baseline was analysed in a total of99 cases (n = 140 with no disability, n = 59 with disability). The fullodel significantly predicted disability (chi-square = 40.58, df = 3,< 0.001). All three factors significantly predicted disability in theodel. For pain at baseline the OR was 3.23, which means that being

n the pain group at baseline increased the odds of being in the dis-bled group by 3.23 times. For disability at baseline the OR was.21, and for sick leave at baseline the OR was 3.08 (see Table 5).

.6. Sick leave

The prediction of sick leave based on work-related factors wasnalysed in a total of 191 cases (n = 147 with sick days < 7 days,= 44 with sick days > 7 days). The full model was not signifi-ant (chi-square = 8.24, df = 5, p = 0.143). The prediction of disabilityased on personal factors was analysed in a total of 192 casesn = 149 with sick days < 7 days, n = 43 with sick days > 7 days). Theull model was not significant (chi-square = 10.52, df = 7, p = 0.161).he prediction of sick leave based on pain, disability and sick leavet baseline was analysed in a total of 199 cases (n = 154 with sickays < 7 days, n = 45 with sick days > 7 days). The full model sig-ificantly predicted sick leave (chi-square = 10.98, df = 3, p = 0.012).isability at baseline significantly predicted sick leave as a single

tem in the model. The OR was 3.67, which means that being inhe sick-leave group at baseline increased the odds of being in theick-leave group at follow-up by 3.67 times (see Table 5).

. Discussion

The main findings in the present study were that personal andutcomes factors such as pain, disability and sick leave at baseline2003) predicted pain, disability and sick leave at follow-up (2006).ain at baseline predicted pain and disability at follow-up. Pain,isability, and sick leave at baseline predicted disability at follow-p, while disability at baseline predicted sick leave at follow-up.one of the work-related factors showed any predictive value forain, disability, and sick leave at follow-up.

Previous studies have shown that back pain is a predictor ofack-related pain and disability among nurses [5], and that amongorkers with LBP, individuals with high pain intensity or disabling

BP are more likely to have MSP [23]. Pain, especially persistentain, has been shown to be associated with increased incidence ofther symptoms (e.g., depression, anxiety and other somatic symp-oms), limitations and negative consequences in daily life, includingoth work and leisure time [36]. Greater self-reported pain andunctional disability at baseline has been shown to predict disabil-ty in patients with back and mixed injuries [24]. Thus, our findingsupport the results of previous studies. We found that sick leave ataseline predicted disability at follow-up and disability at baselineredicted sick leave at follow-up. One explanation could be thatick leave may create new problems, such as increased pain andnactivity [25,36].

Personal factors at baseline (2003) were shown to predict pain,isability and sick leave at follow-up (2006), although the oddsatios were low. Two personal factors – self-rated health and sleepuality during the past week – predicted pain at follow-up. Othertudies [26–28] have shown that sleep problems are more common

al of Pain 1 (2010) 160–166 165

among health care personnel on rotating work shifts, which was thecase for several of the RNs in the present study. The personal fac-tors age and self-rated health significantly predicted disability, butin these cases the odds ratios were low. Studies [36] have shownthat the prevalence of persistent pain generally increases withincreasing age. A systematic review [20] of predictors of chronic dis-ability in injured workers showed that older workers have pooreroutcomes, such as greater pain and functional disability. In thepresent study, the personal factor considering yourself as optimistor pessimist decreased the odds of being in the disabled group atfollow-up. This means that RNs who perceived themselves as beingmore optimistic reported less disability than did RNs who perceivedthemselves as being more pessimistic. Studies [29,30] have shownthat optimism is associated with less depression, greater well-beingand health benefits in different populations.

Our finding that the work-related factors, as a group, did notpredict pain, disability and sick leave at follow-up is at odds withprevious research. Previous studies [12,31,34] have shown thatwork-related and personal factors play an important role in thedevelopment of pain, disability and sick leave. One explanation forour results, owing to the fact that we used a non-clinical sample,may be that persons with pain, disability and high levels of sickleave prior the follow-up in 2006 changed wards, moving to depart-ments with lower-exposure jobs (i.e., less heavy lifting and manualhandling of patients).

Some limitations of the present study deserve mentioning:Firstly, regarding whether the results may be generalized to allRNs, this study was limited to one county in Sweden. However,the present RNs would seem to be typical in terms of their paincomplaints and sick leave. It must also be noted that 97.5% of theRNs were women, thus no comparison with respect to gender waspossible. The sampling differences across studies must be takeninto consideration before discussing the results. Physicians, nurses’aides, and nurse assistants have been included in some previousstudies, which can make it difficult to compare the results in thepresent study with previous results. Secondly, the use of visualanalogue scales for the measurement of several of the variablesmay introduce bias because of well-known problems with this typeof scale, e.g., requirement of intellectual capacity. We judge thatthe participants in our study were capable of using these scalesappropriately. In general, and in spite of potential shortcomings,the visual analogue scale has been shown to have acceptable psy-chometric properties [32]

Thirdly, the use of a cut off at 20 points to categorize participantsas disabled was arbitrary, although we judged that a cut-off valueat 20 points would represent some limitation. Thus, with anothercut off we might have obtained different results.

The strength of the present study was its longitudinal design,which made it possible to predict pain, disability and sick leaveover time.

In the present study, MSP was a common condition amongthe RNs, especially pain in the shoulders, lower back and “otherpain sites” (e.g., leg, hands, ankle). These results are in line withother studies [10,12] showing that MSP is common among nursesworldwide. The major results of the present study support earlierfindings regarding the ability of pain, disability, and sick leave topredict outcomes related to the same factors longitudinally [20,36].The present mixed findings on work-related and personal factorsindicate the need for further research in this area. Attention to indi-vidual factors, such as personal values related to daily life, may beneeded in prospective studies of persons working in the health care

sector who are at risk of developing pain and disability.

Conflict of interest

The authors have no conflict of interest in relation to this study.

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66 A. Nilsson et al. / Scandinavia

cknowledgements

The present study was supported by grants from the Depart-ent of Caring Science and Sociology, University of Gävle. We will

lso thank all the registered nurses who participated in the study.

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